Hello Space Fans and welcome to another edition
of Space Fan News.
Dear Dark Matter,
You are really starting to irritate me.
It's bad enough that you won't interact with
me in any way: I can't see you, smell you,
touch you or otherwise sense your existence
in any way.
I try very hard not to take that personally,
but this is really starting to get me down.
You make up 80% of the mass of the universe.
EIGHTY PERCENT!
Now I realize you probably feel aloof and
all high and mighty because of that, but come
on!
Why you gotta be like that?
You should at least try to interact with us
once in a while.
We need to find you.
We're looking really hard because we need
to know you're there - it's important because
our galaxies don't rotate right without you
and gravity gives us wonky results if you
turn out to be the scientific equivalent to
unicorns and fairies.
Can you help a species out?
Love always,
Tony
PS.
The same goes for your pal dark energy.
OK, now that I have that out of my system
I can tell you what all that was about.
This week, astronomers from ESO, using telescopes
high in the Chilean mountains announced some
results that really put me off.
Now don't get me wrong, they actually did
a very cool thing: they carefully mapped the
motions of more than 400 stars up to 13 000
light-years from the Sun.
Then, from those motions calculated the mass
of all that material in the vicinity of the
Sun, which is a volume four times larger than
ever measured before.
I actually thought this was a great idea.
I mean, we think dark matter is out there
so why not look for it close by where we can
make really accurate measurements and see
how much there is in our backyard.
Well guess what?
It all matched!
All the matter they could see within 13,000
light years - stars, gas, dust, all of it
- matched the mass they calculated from the
motions.

Why is that so irritating?
Because if it all adds up, then it means there's
no room for extra stuff - you know, the stuff
that's supposed to be there but we can't see
it?
That's right, the stuff I gave to all the
kids for Halloween last year: dark matter.
Apparently there's none anywhere near us.
There's no reason it shouldn't be there either.
According to our observations of the Milky
Way, the galaxy is rotating much faster than
the visible matter alone can account for.
The stars only travel the way they do because
there must be something we can't see affecting
their motions.
The amount of material we can see through
all wavelengths and telescopes isn't enough
to make them move that fast.
And it isn't just our galaxy.
All of the galaxies we've looked at have strange
rotation curves that are faster than can be
accounted for by the observable material.
So there HAS to be something we can't see
affecting the way they circle around as the
galaxy rotates.
There has to be!
According to our models, the Milky Way has
a halo of dark matter that looks like this.
See?
It's pretty much even all over the place,
so there's no reason there shouldn't be some
near the Sun.
In order for there to still be dark matter
and agree with the observations from the ESO
guys, then if it's there, then it has to have
some really weird distribution around the
galaxy, like an hourglass or some equally
unlikely shape to avoid having any near here.
So if dark matter isn't present where we think
it ought to be, then we have to come up with
some other explanation for the missing mass
problem.

Stupid dark matter.
You'd better show yourself pretty darn soon.
Next, on a lighter note, the Hubble Space
Telescope turned 22 this week!
To celebrate, the Hubble team has released
this image of a huge star forming region in
the Large Magellanic Cloud, aka the LMC.
The LMC is a dwarf galaxy right next to us
and it hosts one of the largest star forming
regions anywhere.
This stellar nursery is larger than anything
we have in the Milky Way.
Known as 30 Doradus, it is located in the
heart of the Tarantula nebula - a star forming
complex 170,000 light years away.
Here is where they are: this is a time lapse
taken from ESO's Paranal location in Chile.
You see those two very large blobs rotating
near the horizon?
Those are the large and small Magellanic Clouds,
they can only be seen in the southern hemisphere
and the Tarantula nebula is in the larger
blob.
The stars here are millions of times more
massive than our sun.
The image is roughly 650 light-years across
and contains some very active stars, including
one of the fastest rotating stars as well
as the highest velocity stars ever observed
by astronomers.
Here we can view all stages of star birth,
from embryonic stars a few thousand years
old and still wrapped in cocoons of dark gas,
to behemoths that die young in supernova explosions.
This nursery churns out stars at a furious
pace over millions of years and we can see
star clusters of various ages, from about
2 million to 25 million years old.
The region's centerpiece is a giant, young
star cluster named NGC 2070, which is only
2 to 3 million years old.
There are roughly 500,000 stars here and it
is a hotbed for young, massive stars.
Its dense core, known as R136, is packed with
some of the largest stars found in the nearby
universe, weighing more than 100 times the
mass of our sun.
Happy Birthday Hubble!
Here's to 22 more years….
Finally, the Space Shuttle Discovery barnstormed
over Washington D.C. this week on it's final
flight ever.
The specially built 747 used to take the shuttles
from California back to Florida when weather
didn't permit landing at Kennedy Space Center
- ferried it one last time to it's permanent
retirement home at the Smithsonian Air and
Space Museum at Dulles Airport.
It looked a little haggard as it made it's
way: dark streaks covering the white paint
stood in stark contrast to the Enterprise
- a prototype glider that NASA used for test
flights early in the shuttle program.
But then hey, what do you expect?
Let's see how you look after 39 missions,
365 days in space, orbiting the Earth 5,830
times, traveling 148,221,675 miles and dealing
with re-entry.
Anyway, since it's so close by, I plan to
make a trip down there to pay my respects
and see it up close and personal.
After all, this is the least I could do for
the shuttle that put the Hubble Space Telescope
in orbit and fixed it all those times.
Thanks Discovery.
(Boy, I am doing an inordinate amount of talking
to inanimate objects in this episode)
That's it for this week Space Fans, thanks
for watching and, as always, Keep Looking
Up!
