our YouTube channel mr. grant justice
give him a hand alright check this
alright let's go ahead and get started
good evening ladies and gentlemen and
welcome to the Space Telescope public
lecture series I am dr. Frank summers of
the office of public outreach and it is
my pleasure to be your host when you
came in you came in early you might have
gotten a picture of the star cluster
westerlyn - if you came in a little bit
later we ran out of westerlyn - and now
we have the star-forming nebula and 90
available if you get these the n 90s are
still available if you want the
westerlyn - well you might have to trade
with somebody okay so do your best horse
trading and you can get your wonderful
pictures if you'd like to know more
about them of course
turn over on the back and we have a
short essay tell you about them art
topic tonight a fun one mapping the
United Federation of Planets and
astronomers guide to the galaxy and of
course everyone recognizes that the
United Federation of Planets is a
reference to Star Trek and mia has told
me that yes she will tell you where the
Klingons are all right
next month
Susanna days - ah we'll be talking about
the plumes of Europa ice water life find
out next month April 3rd in May one of
the talks we've been trying to get for a
while recently won a Nobel Prize
gravitational wave astronomy a new
method for examining the universe that
we can now finally detect gravitational
waves
we've only been trying for about 40 or
50 years to see what we can do we can
finally detect them and Andy Frick
tourism will Fisher will speak on one of
my favorite nebulae in the entire
universe the Orion Nebula
it is the nearest large star-forming
region is our template for understanding
star formation in the universe and the
guys here know so much about it he'll
give you all sorts of cool detail on how
stars are born actually not only stars
but also planetary systems all right
that will be in June the details are on
our website in your favorite search
engine type in Hubble public lectures
and you should find this webpage where
we have the list of the upcoming talks
oh by the way I see me above all is on
undergrad from not 2016 so she has
spoken here before that was just a
screengrab I did here we also have the
online the live the YouTube and stsci
webcasting as well as the archives the
YouTube goes back to 2014 the webcast
goes all the way back to 2005 that's a
lot of astronaut astronomy topics I dare
you to binge watch that in one weekend I
don't think you can do it if you would
like to be informed we have our sign up
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unsubscribe if you would like the
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sign up to the website or if you can't
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hand it to me and I'll make sure you get
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social media Hubbell web and stsci have
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occasionally write some blog posts if
you want to hear more from me
unfortunately if you looked up you could
not see any stars tonight it's cloudy
it's actually is gonna rain and possibly
even snow a little bit tonight so ya
know Maryland Space Grant Observatory
tonight but if you go to md dot space
grant o RG you can find this
and they have open houses every Friday
you want to check this page for the
observatory status right over here on
the right-hand side and they'll tell you
whether or not they're gonna be open on
various Fridays okay and now the news
from the universe for March 2018 and
since our speaker has chosen a sort of
Star Trek theme to her talk I decided I
would add a little bit of Star Trek
flavor to my news summary so our first
topic is what factor 500 million when
I'm talking about warp I'm actually not
talking about the Star Trek warp I'm
talking about warped images and this is
Baltimore's Inner Harbor with a Saturn
mass black hole passing over the Inner
Harbor and you can see that the images
of the background buildings are warped
by the passage of that black hole
because due to general relativity mass
bends the mass bends space which changes
the direction of light so as you look
past a black hole thing the light goes
around in different directions and it
warps the images of the background
objects it doesn't actually warp the
background objects but it warps those
images now that cannot just happen here
in Baltimore actually it's never
happened here in Baltimore that's just
an example but it can actually happen
out in the universe in clusters of
galaxies these clusters of galaxies have
so much matter more mostly dark matter
in them that they are massive enough to
bend the space around them which
actually changes the direction of the
light passing through them we call this
gravitational lensing gravity changes
the direction of the light and it acts
like a lens in space so if you've got
this lens in space and you've got a
telescope lens this actually acts as an
extra lens to magnify and amplify the
light of more distant objects
using these gravitational lenses we can
see some of the most distant galaxies
out there and so in this cluster called
max Jo for six oh six for seven plus
seven oh one five they don't have any
great names they're usually just phone
numbers like that we actually found a
really really distant galaxy and there
are actually three images of it the
light from this extremely distant galaxy
passes three ways through this cluster
and appear here here and here and you
can see it's beautiful it's a red dot
okay
that's because it's a galaxy about 13
billion light-years away one of the most
distant we've ever seen and when we do
this that's what we usually get we get
red dots because they're very small
galaxies they're very distant and
therefore they're seen in the early part
of the universe okay if it's 13 billion
light-years away you're seeing that
galaxy as it was 13 billion years ago
okay that's only 800 million years after
the Big Bang that's a really baby galaxy
okay but this was something that was
released a few years ago we have a new
cluster that we looked at this one has
the phone number SP T - CL jo6 1 5 - 5 7
4 6 and in this one we do not have a red
dot in this one we actually have a red
streak we have a red smudge so this may
not look like much to you ok so you got
a it's a blur of red instead of a dot of
red but actually by getting a red streak
the gravitational lensing spreads it out
turns it into a streak you can actually
examine some of the internal
characteristics you can estimate it
alright this was found using the Hubble
Space Telescope and the Spitzer Space
Telescope using a program called relics
when they're searched 41 large clusters
of galaxies looking
specifically for these most distant
objects and this object they can tell is
only about 2,500 light years across
now our galaxy is a hundred thousand
light years across so this is tiny
compared to our galaxy our galaxy also
has about 200 billion stars and the
estimate on this is it's about less than
three billion stars okay so it's very
small it's a dwarf galaxy it's only half
the size of what we call the small
Magellanic Cloud which is a dwarf galaxy
that's orbiting around our Milky Way but
you wouldn't expect it to be a large
galaxy because this galaxy is estimated
to be seen thirteen point three billion
light-years away which makes we see it
only 500 million years after the Big
Bang and that's a crucial idea that
galaxies of an order a few billion stars
can form within the first 500 million
years how long after the Big Bang does
it take four stars in galaxies to form
that's one of the great questions in
cosmology that we're pursuing this gives
us evidence that at least you can get a
few billion stars together in one sort
of clump 500 million years later now
Hubble can't can't see the most distant
galaxies because they're red shifted
into the infrared so this is sort of a
precursor for what we will see with the
James Webb Space Telescope that's
currently slated to launch in spring of
2019 so a little over a year from now
the James Webb Space Telescope will
launch and after it becomes observation
operational will get more and more
images like this and you can expect me
to give you more and more stories
looking at the first billion years of
galaxy formation and having much greater
statistics and getting an understanding
of how galaxies initially formed in the
universe so this is a great cool
precursor and I named it warp factor 5
million because using the warp created
by this galaxy cluster were able to see
back to 500 million years after the Big
Bang
our second story lack of j-class
atmospheres raises hopes of m-class
planets alright so if you know your Star
Trek okay you know that almost
everything they visited was oh it's yet
captain it's an m-class planet which
means an earth-like planet okay I'm
actually looked up on Wikipedia today
they have 23 different classes of
planets defined in Star Trek it's I kind
of blew my mind
the specificity they had of these 23
different classes of planets and it
found out that the J class is the
Jupiter class Jupiter Saturn Uranus and
Neptune gas giants although they aren't
the only class of gas giants there's
lots of several different classes out
glassed gas giants I think the largest
is the T class or something like that
I'm not a Trekkie so I don't know all
this stuff but I'm using that to talk
about the planets in the system Trappist
one now this is an artistic presentation
of the Trappist one system we talked
about this before in which there are
seven earth sized planets around a red
dwarf star and this artistic
presentation is supposed to show that
okay here we have the red dwarf star and
here we have steam to indicate it's hot
water would be boiling away here we have
water in its liquid form in the middle
and out here we have water in ice form
where it's cold okay and several of
these planets in the Trappist one system
are in the region where liquid water
would be liquid and that's what we call
the habitable zone all right if you want
a more didactic presentation of it here
is the Trappist one system with the red
dwarf star here and the seven planets b
c d e f g h you've heard of Snow White
and the Seven Dwarfs this is Red Dwarf
and the seven earth sized planets in the
Trappist one system now this is artistic
interpretation okay do we know what
these planets look like no
at all we don't actually see the planets
what we see is the planets pass in front
of the star and block a little bit of
the light so the light for that star
drops and rises back up as the planet
passes in front we call this the transit
method of finding extrasolar planets and
we found seven of these around this star
so we don't actually see the planet but
we could see its atmosphere because when
a planet passes in front of a star some
of the light of the star will go through
that planet's atmosphere and the
chemical elements in that planet's
atmosphere will absorb some of the
star's light so if you take a spectrum
of the star and then you take another
spectrum with the planet in front of the
star subtract the two you get the
spectrum of the planet's atmosphere how
cool is that we can actually start to
see the atmospheres of planets around
other stars so we wanted to tell do
these earth sized planets have
earth-like atmospheres all right and so
what we can tell here is if it has a big
extended atmosphere we'll see a lot of
absorption okay this big extended
atmosphere we'd expect to be hydrogen
puffed up a poor primordial type
atmosphere okay however if it has a thin
atmosphere sort of like mercury I mean
Venus Earth and Mars have today it's not
probably mortal it's processed it has a
good good amount of heavier elements in
it well then it would have a thinner
atmosphere and we'd see almost no
absorption okay so if it has a big
atmosphere we're gonna see absorption if
it has a small atmosphere we're not
going to see absorption all right here
is the actual data ok presented in an
artistic fashion the purple is what we
would expect if it had this large
primordial atmosphere the yellow is the
actual data and you can see that the
actual data in the yellow it's
consistent with basically a flat line
not the big up-and-down that we see in
the primordial atmosphere so for these
four planets three of them D F and E all
in the habitable zone we do not see a
large primordial atmosphere G we're not
quite sure of okay then we need a little
bit more we can't say with absolute
certainty that G doesn't have a big
atmosphere most likely it doesn't but
you know we we have we have certain
measures of this and this one's not good
enough to say for sure so this lack of
this j-class atmosphere indicates that
it could have an m-class atmosphere but
does it say it absolutely has an m-class
atmosphere no it just says it doesn't
have a doesn't have a large extended
atmosphere which adds to the hope that
these could actually be more earth-like
they're not neptune-like okay
sometimes we think of these Earth's
earth sized objects they could be super
Earths that could be mini Neptune's
these are not mini app Tunes okay they
don't have extended atmospheres like
this so one checkmark yes in terms of
moving forward in terms of trying to
find earth-like planets we know their
earth sized now we're continuing to try
and find out if they're earth-like and
this is a good as a good sign moving
forward in that direction again we will
find more out by when we have infrared
observations of the James Webb Space
Telescope
because extrasolar planets actually
shine in the infrared they're brighter
in the infrared especially relative to
their host stars so again pointing to
the future we're going to have a lot
more of these types of stories as well
when the infrared Space Telescope the
tip is up there in next juice next year
and the year after okay all right and so
that is our news from the universe our
featured speaker tonight is MIA boville
who has this is like your third time
talking here right she's coming she's
wonderful because she comes and she
volunteers for me every year okay there
are a number of speakers who
you know I have to with Trista arms to
volunteer once every five or ten years
okay but dia has come in and last time
you talked on the the Harvard Harvard
computers right that's what I would like
to call them okay and tonight she is
going to talk to you about the science
of observing the galaxy with a wonderful
Star Trek flare so ladies and gentlemen
miss Mia Bullough I will call you doctor
I missed you there we go so first off
I'd like to apologize to every single
person in this room in a red shirt all
right now like a good scientist you cite
your sources so for the science chunk of
this talk I used galactic astronomy this
is the one of the Bible's of our
galaxy's course when I'm gonna cover the
mapping of the Milky Way is a month in a
graduate-level galaxies course and I'm
going to attempt to do this in 40
minutes so I might lose leave a few
things out and for the rest of it so
this is the Star Trek Star Trek Atlas
actually had to order this from San Luis
Obispo California because apparently
it's no longer in print but for is the
act for the mapping of specific worlds
to specific xual real stars which I'll
get into towards the end of the talk
this is what I used if anybody is a
bigger Trekkie than me and wants to take
issue with exactly what star I plotted
just look at this first and I'd like to
just point out that I do have a towel in
my back
all right so just to get this out of the
way Star Trek is wonderful it does a lot
of things really really well science is
not one of them so this is a list of the
things that Star Trek roughly speaking
gets right we live in the Milky Way
galaxy the Milky Way galaxy is about a
hundred thousand light-years across
there how much of that is them getting
it right and how much of that was dumb
luck I'm not actually certain there are
nebulae in the Milky Way they won't eat
your ship they won't corrode your ship
and they are significantly bigger than
your ability to jot in and out at
impulse there are stars in the Milky Way
many of those stars have planets in fact
we have been finding a lot of them this
is as of December of 2017 and it
probably needs to be updated
the Kepler this is the full thing of the
Kepler space telescope so this is all
the one planet systems two three four
five six this is the Trappist one system
that dr. Sommers was talking about our
solar system and the Kepler 90 system so
there are planets around stars in fact
there were a lot more planets around
stars and we thought there were some of
these planets maybe in the habitable
zone of their star and by habitable zone
I do not mean m-class with the Vulcans
on them I mean they are at the right
distance from their star to have liquid
water on their surface
which means you've got a chance at
actually having life whether that life
becomes intelligent and develops warp
drive well that's a complete other set
of questions there are such things as
neutron stars pulsars black holes dark
matter and supernova explosions the
statistical chance that they used these
correctly in any given Star Trek episode
is about 10%
they do occasionally get this right but
more likely than not they get it wrong
and no you cannot punch your way through
the event horizon of a black hole but
primarily space is big however big you
think space is it's bigger
however weird do you think spaces it's
weirder so now that we've gotten that
out of the way before you the enterprise
you can tell the enterprise or whichever
a particular starship you're on to go -
I don't know insert techno babble here
in the sector first you have to know
where on earth that sector or in the
galaxy that sector actually is and these
are actually the only two good images I
could find from Star Trek episodes of
the various characters standing in front
of a map but before you can start to say
where did the enterprise go you first
have to figure out where we are and that
starts with a very seemingly simple
question where is the earth located in
our solar system the planets will five
of them are extremely bright they're
very easy to measure in fact we've been
measuring them for thousands of years
but it's actually not so simple because
we'd have to go even further back in
time back to 270 BC and the Golden Age
of Pericles as Athens this is
Aristarchus of Samos and he went against
the grain a little bit he believed the
Sun was at the center of the solar
system that other stars were extremely
far away and that they there were other
stars like our Sun and that's why as the
earth moved around the Sun we didn't see
those stars stars move against the sky
however he was only one voice and at the
same time there was some pretty big
voices saying that no no no the Earth's
at the center were stationary everything
moves around us and this was Aristotle
here and Ptolemy as in the Ptolemaic
system
he gets he's the poor schmuck that gets
this named for him now you have the
earth here at the center you have the
moon going around and you have the Sun
going around all in perfect circles
however the problem is that if you
actually look at the movement of a
planet on the sky it'll kind of go this
way a little bit and then it'll kind of
go this way again and then I'll go back
this way and the part where we went
backwards was retrograde motion and if
everything's just orbiting the earth
happy as you please you're not going to
have retrograde motion so they inserted
what they called epicycles on to each of
these orbits depending on how much of
the time the planet went backwards and
how frequently it went backwards and
they and this worked they could predict
with those circular orbits around the
earth and epicycles they could roughly
get the predict to the positions of the
planets because that's your Holy Grail
that's what you want to do you want to
be able to predict where the planets are
going to be the problem is that as you
move forward in time the model kind of
fell apart the predictions with just one
epicycle weren't working now if that's
getting further and further off the
actual position of the planet you would
think well maybe we should go back to
what that other guy was saying and try
heliocentric they just added more
epicycles there's a principle in science
called Occam's razor it's that the
simplest solution is probably the best
so we're gonna jump forward to 1609 this
is about 30 years after Nicholas
Copernicus once more resurrected the
idea that yes the Sun is at the center
of the solar system but like
Aristophanes and Aristotle and Ptolemy
he assumed the planets were on circular
orbits perfect circles enter these two
gentlemen this is taco Brockie he was
probably he was an incredibly fast
talker he somehow convinced the King of
Denmark to give him a castle and build
him the most state-of-the-art
observatory in Europe I really want to
know how he did this because I've got
grant proposals do
for 30 years he puts together the most
accurate set of measurements of the
planet in existence
he's able to do because he has these
huge instruments this is a Sexton that
allows him to measure very accurately
the positions he's still going by
naked-eye he's not using a telescope
Galileo gali hasn't happened well he's
alive but he hasn't actually aim to
telescope at Jupiter yet and after 30
years of developing all of this data he
passes that data off to Johannes Kepler
and that's a name that if you've been
following all the planet formation we
named a planet finding mission for him
very very good reason brah he tells him
look at Mars Mars is the weird one if
you can solve Mars you can solve all of
it and Kepler keep in mind there's no
slitaz there's no computers for the
younger people in the room there is no
scientific calculators for the slightly
older people in the room and slide rules
haven't been invented yet for the rest
of the people in the room this is what
Kepler figures out that the orbits of
the planets are not circular there are
ellipses now it just so happens for the
orbit of the earth if I were to plot a
circle on this slide and then plot the
orbit of the earth on top of it you
would not be able to tell the difference
it's extremely close to a circle but for
some planets this is the inner solar
system like Mars they're further off a
circle the further off a circle the more
elliptical or eccentric is the term we
use the orbit is then we're clear this
comes the more clearly this comes
through so we have the Sun Mercury Venus
Earth Mars the asteroid belt which we
know is there but they didn't they knew
about Jupiter which is here and Saturn
that's it Uranus and Neptune we'll have
to wait for telescopes to be discovered
and there is no way they know about
Pluto regardless of its status and just
as a reminder that we are already very
much in
all of the green things on here are
space missions which are currently out
there that is the location of all of the
space missions in our solar system as of
this year this is pioneer 10 pioneer 11
and Voyager 1 and Voyager
or I guess feature is what it ends up
one and two are going off in different
directions for the edge of our solar
system so there's a reason we named a
plan to find a mission for this guy so
we now know that Earth is the third
planet orbiting a relatively boring g2
star we're actually lucky it's boring
but how far away are those stars so we
know they must be pretty far but how far
are they actually and now we need some
audience participation without hitting
the person next to you or hit the person
next to you if you don't like them hold
your finger out in front of your face at
arm's length all right if you can wink
between one eye and the next do that
otherwise use your hand does your finger
move yes all right now stop using your
finger and do the same thing with my arm
now do this with my hand put your hand
down and jump between and does my hand
move a little for the people in the
front a little for the back no that is
parallax every single time you walk down
the street and don't run into something
you're using parallax and that's the
fact that your eyes are separated is
actually allowing you to have depth
perception for those of you with glasses
and I mean the people like me whose eyes
just don't work if you've ever taken off
your glasses you'll promptly run into a
wall that's why so when you take this
and instead of being our eyes and our
heads you actually talk about the earth
you have the earth has an orbit it is
one astronomical unit about 93 million
miles from our Sun and if you look at
service star in January and observe that
same star in July sir here's your star
and you look at it if that star is close
enough it'll appear to shift just like
your finger did this is parallax the
baseline that we have is 2 astronomical
units
that's how wide it is the wider the
baseline the larger the angle the closer
the object the wider the angle and the
further away an object is the smaller
the pair the smaller the amount of
parallax you will see and it turns out
that there are not many formulas in
astronomy that are this simple turns
this is the distance to the object to a
star this is the parallax in arc seconds
so does everyone here have a sense of
what a degree is on a circle if you were
to draw a circle you have in a sense of
how much of that circle is a degree now
imagine if that degree is the equivalent
of an hour of time an arc second is one
second to that hour it is 136 hundredth
of a degree I could try to draw that on
an arc on this but you would list see an
infinitesimal line if even that this is
an incredibly small measure and it is at
least two orders of magnitude smaller
than what the person with the absolute
best vision can see with our naked eye
again those of us with glasses need not
apply it turns out that one that if you
if something has one arc second of
parallax or if this shift is measured as
one arc second it is three point two six
light-years away we call that a parsec
this is the primary unit astronomers use
it has nothing to do with the Kessel run
and it is not a unit of time so I didn't
say Star Trek was the only science
fiction universe that messes the science
I don't think they were looking things
up in dictionaries so they start they've
known that this was gonna happen if the
Sun was at the center and the earth is
moving around it you know the stars are
going to have parallax and they've been
looking for this for about 2,000 years
it takes until 1838 for us to have the
technology to measure parallax and that
is because to measure parallax you have
to measure one-tenth of an arc second
in 1989 a catalog of extremely bright
and sedan nearby stars was identified
this was called Hipparchus it was one of
the first attempts to do a large
catalogue of these stars and you get
parallax's for them in 2013 the Gaia
space mission was launched by the
European Space Agency just as an aside
the process of mapping the Milky Way is
very much an international endeavor this
is the Gaia spacecraft while an artist's
rendition of the guy spacecraft were not
out in space in the Milky Way isn't that
pretty this is a parkus so this is the
amount of parallax the mission can
measure in arcseconds all of these
points so this is taco bra he actually
liked the taco bar he the guy that
convinced the King of Denmark to build
him an observatory it also got his nose
cut off in a duel so this is about 1,600
you have Hipparchus in ancient greece
that attempted this with a thousand
stars and then you can actually see the
technology improving the blue line is
how accurate your measurement has to be
to be able to observe parallax around
the nearest star to the Sun which also
happens to be in the wrong hemisphere
forever Greece its Alpha Centauri it's
in the southern hemisphere so you
finally get down to the apart cos
mission this is 120,000 stars a little
later there's a reason I'm explicitly
mentioning this one and then
2013 is the launch of Gaia which is a
billion stars and Gaia is measuring
parallax of 100 100 thousands of an
arcsecond
so if a degree is an hour this is a
hundred thousandth of a second is how
accurate Gaia is that kind of accuracy
the increase in accuracy means increase
distance to which we are able to measure
parallax and Gaia for the brightest
stars is going to get all the way to the
galactic center so we have parallax we
can start to observe stars right now we
can go out to about a hundred to a
thousand light-years depending on the
star we're looking at and that is step
one so determining distances the
determining where something is on the
sky we've actually gotten pretty good at
it's actually called astrometry that
okay something else start recovering
pastrami tree is the location of things
on the sky figuring out the distance is
a whole different game and it is a we
call it the distance ladder the first
rung of that distance ladder is parallax
is just using the shift of the Stars
second our things we call standard
candles and they're not actually these
kind of candles these are astronomical
sources so you have a source that is a
standard candle it can be a star it can
be a supernova whatever it is what's
important is that you're able to get its
absolute brightness its luminosity by a
different means from physics from its
period period develop of its brightness
auscultation something and then some
distance away you have the observer I
thought about doing a cute picture of
the enterprise but they're not always on
earth and the way that this works is
actually relatively simple you have the
luminosity of the object which you're
able to figure out by some means you
have the apparent brightness that we
measure on earth and the distance
between that object and us
it's simply the luminosity over the
apparent brightness there's some
physical constants and things in there
and the distance is if this is actually
distance squared but this once again
this is very simple very very
straightforward in fact this is the same
1 over R squared law that governs
gravity so we're gonna jump forward to
1900 Bell back actually I guess to 1908
and work by Henrietta Swan Leavitt she
worked with she was among 220 computers
these actually were women that were
doing computing again these things
called computers apparently in 1950 they
took up the size of a room or so my
father tells me and Henry gonna leave it
was only one of them the work that they
did actually forms the backbone of our
understanding of the Stars and just as a
note since it is Women's History Month
140 of the names are known 80 of them
are not we only have initials Henrietta
Leavitt was she had an undergraduate
degree in astronomy and she was given
the task of looking for variables not go
look at these specific variables just
here's some glass plates that they were
actually glass you can see a crack here
these are actually glass plates some
people in the room may remember remember
film cameras I think some of you may not
instead of film this actually was you
would take it on a silvered plate of
glass this is the SMC in a much in a
more modern image of the Small
Magellanic Cloud this is a image a
period image of the small magic club
with her notations on it
these are her notations and she noticed
that there were class of variables in
the small magellanic cloud that were
very distinctive they rose in brightness
there were stars that rose and
brightness very quickly and then fell
off and then rose and brightness again
and then fell off these work they named
them sets for the prototype prototype
star for which they were identified and
since she had the SMC she had that she
knew they're all at the same distance
they're basically all at the same
distance and the brighter sets had
longer periods as of 2009
we actually call this the leave it law
this is the first standard candle you
now if you know the period of a Cepheid
you go up you have its period you go up
and you can read off its absolute
brightness its luminosity if you have
its luminosity you have its measured
apparent brightness you have its
distance and Cepheid are bright we can
see these in external galaxies they also
are not that rare and this is what you
have to do to jump a rung at the
distance ladder it's not as simple as
doing this first off you find a Cepheid
that's close enough to also have a
parallax measurement then you calculate
the distance to that Cepheid using
parallax and using the distance modulus
or using the relation between absolute
luminosity apparently parent brightness
and distance you calculate the
luminosity of that sefie you then use
that luminosity to calibrate the leave
it law to calibrate henriette leave its
relation because you need to know where
things sit on the luminosity axis does a
Cepheid with a period of two days have a
luminosity of ten times the luminosity
of our Sun or a hundred that because
that's a very very that's a very large
error that you're introducing in your
distances you then use your calibrated
leave it law to get the luminosities of
Cepheid x' for which you know their
period sophia's which are too far away
for parallax you then use this except
the Illuminati and the apparent
brightness and you calculate the
distance simple turns out there sophia's
are not the only standard candle and
focusing only on ones used to map the
Milky Way there's a whole long list of
these this is spectral class or color of
a star from red to blue versus its
absolute brightness our Sun sits right
here on the main sequence all these
stars are burning hydrogen are fusing
hydrogen to helium in their cores and
this is where stars will spend the
majority of their life
and they're stable when they're on this
however once they move on off it they
become unstable and they move through
something called an instability strip
and these are where a lot of variable
stars are you can see this is the
prototype for the Cepheid archetype for
the Cepheid and this is the archetype
for another class called the RLI right
like the Cepheid x' they have a relation
between their luminosity and their
period and um but unlike the Cepheid x'
they are they are older so you can find
these in evolved stellar systems and
that's going to be important in a minute
so we now know how far the stars are
away and that is somewhere between 4
light years and about a hundred thousand
light years
I warned you space was big now where is
the solar system in our galaxy so we're
going to jump back to 1772 to William
and Carol and Herschel they were brother
and sister
astronomers living in England in the
18th century I think something else was
going on with England in 1772 but you
know just small occur falafel with you
know some problematic colonies and
really and Herschel based on
observations of stars came up with a
model of the Milky Way which you can see
here he notices that when you look up
have seven it has anyone here seeing the
Milky Way in a dark night all right you
see the arc of it so there's a
high-density area of stars and fewer
stars above and below so he has that
here you can see that there's definitely
a direction in which there are more
stars this is where the Sun is
I just want wild guests about whether or
not this is right no any time we're at
the center of the universe you have a
problem it's actually called the
Copernican principle never put the earth
at the center of the universe or in a
corner
so but to fully solve this problem you
had to wait a hundred and fifty years
this is how well shapely he was actually
the second director of the Harvard
Observatory and he used our alive I
variables remember that second standard
candle and was able to get the distance
to globular clusters and unfortunately
the telescope's not working but
globulars are very dense massive
clusters of stars that orbit our Milky
Way and if these are things that are in
the halo and the outskirts of our galaxy
and you look at and you can measure the
distribution if the Sun is at the center
of the galaxy then the globular clusters
should be centered around us if we're
not at the center of the galaxy the
globular clusters shouldn't be centered
around us and he plotted the
distribution of the globular clusters in
physical space so this is in kiloparsec
so thousands of parsecs or about 3,000
light years per unit versus this is up
and down in the plane so this is the
plane of our galaxy right here and he
found out that lo and behold the Sun is
not at the center of the galaxy I mean
by this I'm sure this was shocking but
the Sun is not at the center of a galaxy
in fact the center point is in the
direction of the constellation of
Sagittarius he believed it was about
fourteen kiloparsecs away he was off by
about a factor of two in astronomy we
call that a narrow bar this is the
diagram of our Milky Way edge on you
have the disk of our galaxy and the
Bulge for the record the ball just not
that pretty the Sun is here about
halfway out on the disk the whole disk
is a hundred thousand light-years across
with the globular clusters orbiting the
entire system so we are not in the
middle of things we are in Loudoun
County
not on the complete edge of things but
you know relatively far out so we know
where we are that we're out on the edge
that we're in the disk of our Milky Way
that the earth is not at the center of
our solar system and that the stars are
very very far away but what does our
galaxy actually look like this is an
image this is a composite image taken by
the European Southern Observatory so
this is you cannot telescope cannot take
this in one image this is actually an
all-sky image it's beautiful absolutely
beautiful the center of the galaxy is
right here but there's something in the
way so this is the disk and there's all
these dark spots these are dust clouds
now this is not the kind of dust yet to
sweep off your floor it's actually good
that you have it these dust tends to
form in areas where there is a lot of
star formation we are actually on a
sitting on a dust aggregate right now in
the early days of our planet the
planetary nebula dust particles started
to clump together and then they become
rocks and then the rocks are banging
into each other and then they become
asteroids and the next thing you know
you have earth but they are a problem
because visible light the light we see
with our eyes cannot penetrate that dust
the dust blocks it so if you want to
observe the center of the galaxy if you
want to observe really anywhere in the
galaxy beyond our little region you've
got a problem the good news is that
there's more light than just visible
light this is the Eagle Nebula the
pillars of creation in the Eagle Nebula
for those of you that remember this was
on the front page of the Washington Post
when the original image came out this is
in visible light this beautiful
multicolored image and visible light
this is the same shot in the infrared so
infrared blade has a slightly longer
wavelength it's slightly redder than
visible light it's how your cat knows
where the food bowl is in the middle of
the night and if you have ever used
night-vision goggles
that's what it
those are using infrared it's also we we
perceive it as heat our bodies are
giving off infrared radiation in the
form of heat but what's incredible is
these stores are here in this image we
didn't just ship them in special for the
infrared exposure it's just in the
infrared light you can look through the
dust and the gas of the pillars to the
Stars behind them and when you do that
for the entire Milky Way things look a
little different this is the Milky Way
this is a composite image in
near-infrared and the near infrared part
of the spectrum you can now see the
stellar disk of the Milky Way and the
stellar bulge
the dust lanes that we're blocking our
view have faded completely into the
background and when we start looking
towards the galactic center which is
about 8.5 kiloparsecs or 25,000
light-years away when we looked in we
find that there is an extremely bright
radio source called sad a star right at
the supposedly of the center of our
galaxy and when we zoom in further we
see that the galactic center isn't just
some stars moving around it's actually a
very complex region and there's this
incredibly bright source at the centre
when you zoom even further in I hope
this works and you look these are this
is the center these are stars this is
not a movie or an artist's conception
this is data this is data taken over a
period of about 10 years for comparison
it will take the earth some 250 million
years to orbit the Milky Way these stars
are moving incredibly fast it turns out
that using Kepler's laws using the laws
you're honest Kepler determined for our
solar system you can take one of these
orbits and figure out how much mass is
in the middle there it's not emitting
any light it's very compact and it's
three million times the mass of our
this is the supermassive black hole the
center of the Milky Way so if you want
to know where the center of the Milky
Way is that's it right there here's the
and we and again this is where I have to
take what we do in a month and graduate
galaxies and compress it this is the
optical Milky Way disk and optical this
is the near-infrared image that I showed
you before when you look in the
mid-upper red further to longer
wavelengths you're now seeing the dust
heating up all those dust clouds heating
up that's what you're seeing here when
you start looking at molecular hydrogen
this is hydrogen that's bonded so it's
h2 it's two atoms of hydrogen bound
together this is right this is
relatively cool gas so this is where
stars are forming right here
concentrated in the disk we know that
tells us that stars are forming in the
disk of our galaxy they're not forming
everywhere you start in addition the
atomic hydrogen which is measuring
warmer hydrogen and the molecular
hydrogen together actually we from them
we find out we have an extra spiral arm
apparently we lost it I don't know we
have an extra spiral arm that we only
found in gas and this and in the radio
wavelengths the same wavelengths that
you use to tune your car for the radio
in your car for I'm assuming some people
still use radios in their cars it turns
out that there is yet another distance
indicator our Sun will become will stay
in the main sequence eventually we
become a red giant will become a
planetary nebula which are very pretty
and eventually die as a white dwarf in
stellar evolution terms this is called
going out with a whimper a massive star
and by massive I mean something eight
times the mass of our Sun or even bigger
will become a red supergiant it'll move
around a bunch and then it will undergo
a supernova explosion these are some of
the most energetic events in the
universe and some of these will form a
neutron star these are the neutron stars
two neutron stars that
colliding with each other that was the
recent subject of the first both LIGO
and optical detection for gravity waves
and it turns out that neutron stars in
addition to being the size of a stew
being our mass of our Sun it combined to
the size of Washington DC spin this is
Jocelyn Bell Burnell as a graduate
student she detected a signal each of
these little dips is a pulse from a
neutron star what's happening is you
have the neutron star here remember this
is this is the DC Beltway or the walk or
the Baltimore Beltway since we are in
Baltimore this is the rotation access so
they start spinning this is the magnetic
field on earth our magnetic field lines
up with our pole in reality a neutron
stars it doesn't so if this is the axis
every time you sweep you get a signal
and I'm not doing that anymore because
I'm dizzy this is a cleaner image where
you can see the period and every pulsar
has a unique period and it turns out
that in addition to this the pulses if
there's free electrons or just electrons
flying around in space because of course
there are pulsars tend to spread out the
signal of the Pulsar will spread out or
disperse if you have a pulsar where you
independently know the distances because
why is this going to be the straight
forward you can map the electron density
of the galaxy if you know the electron
density of the galaxy and you can
measure the dispersion for other pulsars
suddenly you know where all the pulsars
are in the galaxy this is the disk of
the galaxy this is a hundred thousand
light-years across
and these are the note these are the
known positions of pulsars in our galaxy
so unlike the Cepheid unlike many other
things this is one of the only tools we
have to really map the far edge of the
galaxy in addition this is something
once in a while Star Trek actually gets
something right I don't remember whether
q or the traveler that flung the
enterprise somewhere but they're trying
to figure out where they are and they
explicitly say check the pulsars and
that is because each pulsar has a unique
period so if you identify this pulsar
this pulsar and that pulsar you now know
where you are and since we I didn't know
if they're gonna be kids in the audience
hence the editing of the of the pioneer
the Pioneer plaque this is this is not a
Hubble image this is an artist's
conception but this is based on data
this is the Milky Way the center here
with a bar we know this based on
kinematics the the velocity and the
movements of the stars in the center of
our galaxy we have two major arms coming
off either side smaller arms here or
minor arms and then there's this
additional arm here this is the one that
we figured out from radio observations
of hydrogen this is what we call the
Orion spur that's a Ryan this is the
earth roughly speaking not to scale by
the way this is the furthest to
measurement we have in our galaxy this
is 667 thousand light-years away if you
remember I told you Star Trek got the
scale the galaxy wrong accidentally if
Voyager got like another 10,000
light-years that would have been out of
the disk just to give you a sense of
this that's what I mean by good I got it
right accidentally this is the earth
this is 67 thousand light-years away
there's about another 20,000 light-years
between us and the edge of the disk and
since you've been so good I promised you
that I would tell you what the Klingons
were at the end of this I believe it
turns out that the planet Vulcan is
orbiting an actual star it's called 40
Eridani
for the nearby stars we actually have
something a little more interesting than
phone numbers it is in the constellation
of air adonis the river which is right
here this is a ryan so if you want to
actually find where Vulcan is in the sky
it's right around here and I had to put
some sort of Star Trek Discovery
reference in here this is literally what
I did in the Star Trek star charts there
is a list of about will actually not
list its maps that have things written
into tight font that wasn't particularly
easy to read but you have a whole bunch
of stars this is 440 Eridani which is
Vulcan in Star Trek
you have the Galactic coordinates so
this is basically latitude and longitude
for a galaxy and this is the parallax
this is how much Epsilon Eridani is
moving if you measure it in January and
June the larger this number is the
closer something is an Epsilon Eridani
or Vulcan is about 16 and a quarter
light-years away so on cosmic terms
extremely close by in absolute terms it
would take a 17 years to say hi and
another 17 years for them to say oh god
this is the Federation every single star
in in Star Trek star charts that was in
Federation space I plugged into the
Sinbad database which is this right
there and pulled out the Galactica
latitude the Galactic longitude and the
parallax which gave me the distances the
Federation can be measured with parallax
that is how small it is the entire
Federation is about to 300 light-years
across depending on if you switch I'll
give them 400 because you've got some
sort of weird squiggly bits to go off to
the side I think this is if you were
looking down into the plane of our
galaxy that's what it would look like so
you have sort of a tail going off here
and this is looking into the disk
towards the center of our galaxy so if
Kirk is on the enterprise on the edge of
the Federation and looks back at earth
with a powerful enough telescope he
could watch his Efrain Cochrane take off
on the first work plate
he couldn't watch us the Federation
isn't big enough for him to be able to
go far enough away to look 300 years
back in time I told you I was gonna nerd
out um turns out the Klingons are closer
than we think they are this is the
distance to all the systems notice
Klingon systems the closest ones are
actually less than a hundred light-years
away and if you want to look for the
Klingon Empire look in the
constellations of Leo and Gemini that's
if you want to look towards the the
Klingon Empire there in Leo it's Leo and
Gemini about a hundred light years away
and I couldn't and I didn't know which
Klingons to use by the way for that
picture I think this is just we got
better at makeup over the course of 50
years the Romulans and of course I had
to use green the black here is the
Romulan neutral zone that's actually
only about 30 light years away they're
actually closer than the Klingons and
the Romulans Empire is at is big it goes
out to about 150 light-years away if you
to see to look towards the Romulans you
actually have to be in the southern
hemisphere in the constellation of
Centaurus in the southern hemisphere and
we have the oops wrong Cardassian sword
the Kardashians are actually in if you
look towards the Big Dipper they are if
you look towards the Big Dipper tonight
you were looking in the direction of the
Kardashian what is it something and
these are the distances this is actually
aren't distances - these are distances
the edge of Cardassian space because
that's all I could find so the answer is
that yes this stuff is a lot closer than
you think they're not 3,000 light years
away but the chance that you could
actually get across 100 that 100 light
years to come and say hi questionable so
just to put this into perspective I told
you space was big this is the Federation
and the Klingon Empire and the Romulans
and the Cardassian this is all of Star
Trek but the exception of the bit that
happened over here and the kind of
happened over here but to give you a
sense of how difficult it is to see
through this massive stuff because
remember we're stuck in the disc we're
stuck right here on earth looking at our
galaxy through it's disc we know less
about Star Trek's Delta Quadrant than we
do about galaxies a billion light-years
away
it's easier for us to find an
information about galaxies on the near
the edge of the universe than it is to
figure out what's going on on the other
side of our own galaxy and it's sort of
as a closing note the Orion Nebula is
the closest major star for me and to our
that was by the way thank you so much
for mentioning Orion that was a perfect
it's about 1,400 light-years away this
is at least a five-year mission this is
not let's go check out the Orion Nebula
and we'll be home next week and to give
you a sense of scale remember we're here
and Orion's here on galactic scales this
is extremely extremely close by as such
even in whatever future we end up in
assuming that we don't accidentally blow
ourselves up in the next 10 years
astronomers are still going to be
studying the universe largely study
the universe the same way that they have
been for the better part of three
thousand years with photons with light
physics and hopefully really awesome
Space Telescope's thank you
all right so um if I rid read that
correctly if we're 1,400 light-years
away to the Orion Nebula the Orion
Nebula is technically not in Federation
space then Federation space is only like
it's a it's a 1,200 light-years beyond
Federation space okay I think the
Federation had better annex the Orion
Nebula gate is that is one of the most
gorgeous places in our galaxy okay so I
think we'll have together well look III
just you know we got a call paramount
and get their writers to get get the
Orion Nebula inside Federation in Star
Trek if you haven't noticed they tend to
move the enterprise moves at the speed
of plot so it's actually very difficult
to figure out how fast are they actually
going and how far are they actually
going all right do we have any questions
for the for our speaker here tonight
yes orange jacket I don't know the
numbers but it is and we repeat the
question for the question is how fast
are the stars our movie and periapsis
that their closest approach to the black
hole I don't have a number for you it is
extremely fast it is fast enough that
when the one of the ones that goes close
enough approaches the black hole they
weren't sure it was going to come out
the other side so they are orbiting it's
a basically I think it's pretty much as
fast as you can go but I don't have an
actual number in meters per second right
I mean for a reference you know the Sun
is moving at what 250 222 kilometers per
second 250 kilometers per second this is
at least a hundred times faster yeah so
but 200 kilometers
second times 3,600 is what like a
hundred and a hundred thousand miles per
hour or something like that if a km/h
right just to give it something these
are moving so fast in space we talk
about kilometers per second not
kilometers per hour okay so we always
have to translate from the numbers that
we know we memorize to the numbers we
can explain
yes question there yes you mentioned
that astrology is one of the things that
Star Trek has done correctly I recall
there were some episodes with a travel
back in time an astronomer tree tells
them what their time that he have
arrived in his mission so the question
was in some Star Trek episodes they
travel back in time and the astrology of
the stars tells them what time it is
comment on that and parallax and
parallax is the star moving the Stars
actually moving with parallax that's
automatic the stars are actually moving
relative to the Sun proper motions are
if we're sitting here and a star is
moving like this this is the amount it
comes across so not along our line of
sight but across that is its proper
motion you would assume that by the time
you got to the world of Star Trek they
would have we were actually already well
into having that mapped and knowing the
proper motions of the nearby stars you
would assume by the time you got to Star
Trek they would have that for a much
larger volume and so you would be able
to say you know Epsilon Eridani is here
but should be here but it's here so it
must be 300 years ago okay all the way
in the back and the redshirt when
galaxies rotate do they all rotate in
the same direction or what direction do
they rotate in it depends on what
direction you're looking at them
and I'm actually not being entirely for
being in in let me talk about things
when we talk it depends on what
direction is up it actually depends on
what you define is up and usually what
we say is if is we use the right hand
rule and we say if you take your hand
your right hand like this feel free to
do this if you without preferably
without hitting your neighbor again and
if you curl your hands like this in a
counterclockwise direction your thumb
points up so we define if you have
something rotating and you have it in
the counterclockwise direction we
defined this as up and so if you were to
take that same object and instead of
looking at it from above you look at it
from below you're now going to have
clockwise rotation and so the direction
of the rotation is very dependent on how
you look if you show the Milky Way the
picture the Robert Hertz diagram in the
Milky Way there we go
we can say about this that they tend to
rotate with the trailing spiral arms we
don't know I think I know of like one
galaxy that might have leading spiral
arms which means that for this galaxy it
would be rotating clockwise okay and
from the direction you're looking at it
okay of course
right just because that the spiral arms
trail okay they're called trailing
spiral arms looking at the same image
from the other side of the disk it would
look like it was rotating
counterclockwise right you know we have
one we have we we can agree on one
perspective here right for this to this
diagram we can also agree that I I know
of like one galaxy where it was so it
was possible that it might have a
leading spiral arm but I didn't believe
it actually so it's all the spiral arms
I know of our trailing do you know of
any okay good all right in the purple
down here so you're not in a red shirt
or a blue shirt you're in a purple shirt
so I guess you're kind of safe
so what happened the universe that we
know they're trying to return where did
they go
are you talking about Star Trek Voyager
okay so where do Star Trek Voyager go
here I told you the 67th on I put this
up for a reason but what is yours here
there they're barely still in the galaxy
because they keep running into people
every other planet there they're barely
there they're barely and they they're
like they're up here okay
over there yes the stars toward the
center of the galaxy versus on the edge
are the ones more toward the center are
they traveling faster or slower so what
are the speed of the stars in the galaxy
going from the center to the edge what's
the relative speeds of those a rotation
curve the motivationally rotation curve
of the Milky Way the rotation speed of
the stars is actually relatively for
constant with distance from the center
of the galaxy and so that means that the
stars in here are actually going at
about the same speed as the stars out
here this is one of the major pieces of
evidence for dark matter actually I told
you Dark Matter exists it just you know
doesn't exist the way that you would
think it would Star Trek
there is right at the center of our
galaxy as we start moving out there is
an increase in speed as you go further
out but once you get certain about to
the orbit of our Sun which is about
25,000 light years out the speed of
rotation is is flattened and is constant
okay in the black jacket there so how
our solar system can be to the center of
the galaxy before becomes on alright so
if our galaxy were closer to the center
of the Milky Way would it be come back
our Sun yes we would the solar system
become in on an
I wouldn't want to be right on top of
Sagittarius a then you might have a
problem but we could be a good ways in
because remember space is really big we
would actually have more trouble at the
center of a globular cluster because of
how crowded things are than we would in
the center of our galaxy so really until
you get to the really close in to the
galactic center you would be we'd be
fine yeah and just to amplify her point
about globular clusters globular
clusters are the only place that we know
of where stars can actually dense enough
that stars can actually collide so I
mean that actually causes that would
cause a lot more problems than billion
years the Andromeda is going to slam
into the Milky Way when that happens
none of the stars are going to collide
that is how much space there is between
the stars are actually going to just
move past each other but we got four
billion years to wait for that so that
makes for a lot of sequels before that
happens all the way in the far corner it
looks very bright in the center of the
galaxy you know we have an issue with
light pollution I think we'd have even
more issue seen through it I mean right
now because we're in the disc so the
milky way across is about a hundred
thousand light years the disc is only a
thousand light years thick you can think
of it as a laser disc it's about the
right dimensions if you're in the center
if you're sort of in the Bulge area here
right now if we look up out of the disc
or down out of the disc we have a
relatively clear view of what's outside
the Milky Way if we're in the middle in
the Bulge you're gonna have to look this
way this way up down you know whatever
direction you choose to look you're
gonna be looking through a whole lot of
stars and so it's actually gonna it's
not so much through you're gonna have
light pollution as it's gonna be almost
impossible to see anything beyond the
Milky Way right and the same is true in
a globular cluster you get in the center
of glory
cluster of a million stars you can do
incredible stellar astronomy but extra
galactic astronomy really kind of
difficult okay so yeah we're actually
kind of lucky being out in the boondocks
we have a nice clear skies and in one
sense like that okay in the blue shirt
right there this the spiral structure
makes me think that the galaxy is
turning is rotated if it's rotating how
can the hour be moving at the same speed
as further okay so if the galaxy is
rotating how can the outers objects be
moving at the same speed is the inner
objects um the answer is actually dark
matter is what dark matter so everything
we see that's visible all the stars the
gas the dust starships whatever
starships hapless bipedal species all of
that is made up of something called
baryonic matter and all of that
interacts with light it either absorbs
light or emits light all of that is
about 10% of the matter in the universe
the other 90% is dark matter and dark
matter we only see dark matter because
of gravity because we know it's there we
know that there if the stars on the
outer edge of the disk are orbiting just
as fast as the stars in the inner edge
then we and we know that the mass of the
Milky Way the enclosed the mass inside
those orbits is basically the same once
you get out here so it should be falling
off like you see like the fact that
Neptune orbits lower than Jupiter which
orbits lower than mercury that's called
Keplerian rotation the fact that we see
this flat rotation constant rotation as
far out as we can observe means that
there must be an additional mass
component which ends up being about 90%
of the mass of the galaxy that just
isn't interacting with light it's not
absorbing light it's not emitting light
and that is dark matter and that's about
90 percent of the
and I'll add one more comment that the
pattern speed of the spiral structure is
different from the orbital speed of the
stars within it stars go into these
spiral arms and move out of these spiral
arms so the patterns speed the density
wave of the spirals actually is a
different rotational speed than the
stars that are moving through them okay
so that's another thing to process it
but the arms well we can't watch getting
we can't watch a galaxy for that to
confirm that but our simulations do show
that the that the pattern that the
pattern stays roughly constant for a
while but they can they can stretch out
and reform and break up in for instance
when the LM if the LMC in the essence
you come too close to the disk they will
actually modify this pattern okay we got
a couple questions from online at warp
9.9 how long would it take for the
enterprise to cross the Milky Way six
that would have been going at maximum
warp it takes a hundred years to cross
the Milky Way maximum warp will warp 9.9
depending on what maximum orb is it's
about a thousand light years per year
hence the reason that Orion is more than
a five year mission okay and let's see
there was a good question what do you
think is the most interesting unanswered
question you have relating to your work
your studies of things well I don't
actually work on the Milky Way I work on
extremely tiny galaxies that are
orbiting the Milky Way and I would
actually say that you know going back to
your first news from the universe point
we don't I work on galaxies very small
galaxies at today in the local universe
and their counterparts in the first
billion years of the universe and how
that happened how different physical
mechanism
regulated an interplay to form those
first galaxies I think is for me one of
the most interesting problems and we are
nowhere near solving it Webb's gonna
help but we need W first as well okay
and one last question from the audience
what's a laserdisc we just got a couple
more minutes yeah okay so what is the
fastest we've sent we've we've created
his net neutral aizen's that's the
fastest chip we've launched and how fast
do you think we possibly can go do you
know how fast horizons is going no we
can call Alan Stern right now we can
only the main way that we get things
moving fast this is true for New
Horizons which recently flew by Pluto
this is true for the Pioneer missions
and for the two Voyager missions is that
as we go out through the solar system we
go by the giant planets and actually the
reason we could do the Pioneer and
Voyager missions when we did is because
all the giant planets were lined up
perfectly right when we had the
technology to do it they just happen to
be lined up perfectly and this does not
happen that often as the planets and so
you swing by Jupiter you get a gravity
assist and you speed up then you swing
by Saturn Neptune Uranus and then
Neptune on the way out do you mean that
we are nowhere near the speed of light
New Horizons is moving at 16 kilometres
a second or 36,000 miles per hour so 16
to give you a sense 16 kilometers per
second is New Horizons and the speed of
light is a hundred thousand kilometers
per second as we approach the speed of
light because of relativity as you start
approaching the speed of light the mass
of whatever you're sending approaches
infinity so we could
something near the speed of light or as
close to the speed of light as we
possibly could but even if we got
something to half the speed of light it
would take eight years to get to Alpha
Centauri and it would take thirty-two
years to get to forty Eridani so unless
unless there's a way around this the
speed of light is the speed limit of the
universe unless there's a way around it
of course it's no fun in you know you
can't have Star Trek if it's like well
we'll get there and about you know
seventy years yeah no that wouldn't make
for a very entertaining show yeah we
scientists are a little bit dampers on
Hollywood script writers that come
around I've gotten a couple of scripts
passed me and not like I yeah this is it
and none of this is possible they don't
listen but because they need it to work
for their story but you know we can give
them our best advice all right here
what's on the other side of a black hole
we don't know physics actually breaks
down inside of black holes so we
understand how things work on quantum
scales we understand our quantum
mechanics works and we've been able to
make quantum forces work with
electromagnetic physics but when you try
to combine those with general relativity
with our understanding of gravity the
equations don't agree and the
predictions don't agree at all and so we
don't actually know what's going on
inside of a black hole because our two
understandings of the universe are
giving us completely contradictory
answers it's actually called the to
unify those to make them work inside a
black hole is one of the Holy Grails of
theoretical physics right now I mean it
could be a wormhole to the Gamma
Quadrant but
well you know we the scientific answer
is that we once you're past the event
horizon we don't know okay we have an
update from somebody online who looked
it up and NASA's Juno was accelerated by
Jupiter and they they quote one hundred
sixty-five thousand miles per hour that
makes you know the fastest moving
human-made object in history okay I
didn't know that Juno had gotten up to
that speed the Juno probe that's
measuring the magnetosphere of jupiter
right now was accelerated when it came
past Jupiter is in this big huge looping
orbit around Jupiter and somebody online
says it's it's now the fastest
human-made object in history okay it's
9:20 for all I give you the honor of the
last question in the back here that
speed is strictly gravitational is
responsible well it it would have
approached Jupiter with similar tens of
kilometers per second speed as is moving
out but then because it came so deep
into Jupiter's gravity well it gotten an
acceleration as it came through
Jupiter's gravity well that increased
its speed so it's orbiting Jupiter with
that speed okay all right so
understanding that meal we'll be back
next year where she's going to disprove
shine Holt's theory of multiple you do
realize I'm applying to jobs in
California right I'm making a Star Trek
reference here okay wine holds your
theory of multiple Big Bang's which is
dependent upon Wang's second postulate
okay and so you have to get past yes we
all know that Wang as Captain Janeway
said
but next month we stay with Susannah D
used wha and in the meantime let's give
a warm thank you to me above Oh
he worked down the bowels of the ship
and he was you know doing the really
boring job
