Hi everyone, I'm Joe.
-I'm Ethan.
-And I'm Brandon, and the video we watched to review the lecture was "Cosmology and Exoplanets: Unpacking the 2019 Nobel Prize in Physics."
The Nobel Prize in 2019 was awarded to two different parties.
The first one was James Peebles "for theoretical discoveries in physics cosmology."
The second was Michel Mayor and Dider Queloz "for the discovery of an exoplanet orbiting a solar-type star."
The video lecture we watched was split into two topics.
The first was cosmology, the study of the universe as a whole,
and the second speaker spoke on exoplanets and how we've been detecting them for the past few decades.
-So, James Peebles was recognized for theoretical discoveries in physical cosmology.
His award was for a lifetime of discoveries that included 40 years' worth of published work.
Peebles is now widely known as one of the fathers of physical cosmology.
A number of his discoveries were highlighted in the video including that of early nucleosynthesis.
-In 1966, Peebles predicted that helium would form [from] hydrogen after the Big Bang.
And then he also predicted the formation of galaxies and calculated how small density fluctuations would lead to galaxies forming.
Then he also explained how galaxies get their spin and co-predicted, with another Russian scientist [Zel'dovich],
the cosmic web, which is the structure of interconnected galaxies, and how there're high-density points versus, like, vacuous areas.
And that prediction was actually confirmed by a Harvard study that observed tens of thousands of galaxies that showed those patterns emerging.
-Uh, moving on to Mayor and Queloz...
Their work focused more on exoplanets.
Particularly exoplanets orbiting a solar-type star, so one like the sun.
Prior to that, the only exoplanets we could see were orbiting pulsars,
which [are] not like [stars].
They're the size of a large city but extremely dense.
-And they're highly magnetized, like tens of thousands of times more magnetized than the sun.
In the '80s, two scientists, Campbell and Latham, unknowingly discovered exoplanets,
because they found, you know, they got some signals of the planets,
but they were sure what the signals they got actually were from.
They didn't know whether they were indeed due to other planets, or whether they were due to a brown dwarf, or anything like that.
So it was never confirmed, and so they basically discovered them without knowing.
And like Brandon said, two planets were discovered orbiting a pulsar in 1992,
but no planets orbiting a sun-like star were found until Mayor and Queloz in 1995.
And they discovered 51-Pegasi b.
-They discovered it using the radial velocity detection technique.
They just detected variations and anomalies in how stars and different objects were moving.
And then their discovery confirmed the existence of other like planets, which revolutionized planet formation theories,
And helped kind of fuel and kick off the search for habitable planets.
And now we actually use a bunch of different methods to find exoplanets.
So there's- there's radial velocity, there's the transit method,
microlensing, imaging, time variations, and orbital brightness modulation.
The main one now is actually transit method, where we use line of sight to see like when- see patterns of when planets pass in front of stars.
-Yeah, I thought that was interesting when- when Professor Li, like explained that at the end.
Like how there's kind of like a sinuous curve of when the planet passes in front of the star,
it gets a little dimmer, and that's how we can kind of detect the period of its orbit.
-I mean, I would've expected that people would think to use that first.
Cause it's easier to say something like you see it, versus you have to calculate like radial velocity, and
And also supercomputers! They talked about the Summit supercomputer from uh, Oakridge National Laboratory.
Yeah, when that video was made, that was the best supercomputer in the world.
That's actually been replaced recently by uh, Fugaku in Japan.
That one [Fugaku] doesn't start operation till 2021.
Well, I was just gonna, like backpack off of that really fast, like
it being able to detect the exoplanets, and like find them even- even better than the supercomputer that we have now,
that's just gonna increase, like, how fast we're finding them, I guess, which
I think they said in the video was already like an exponential rate basically.
And now we're at over 4000, plus thousands of candidates that require further observation, it's just interesting.....
-Yeah. That data's from NASA, by the way, to all our listeners out there.
And they found out that the number of exoplanets doubles every 27 months--number of KNOWN exoplanets.
Which deals with more- the idea more of habitable exoplanets,
and the idea that like, what if there are other living things out there?
I found a lot of stuff in the cosmology half of the presentation to be really interesting.
I don't know if you guys knew this, but I didn't know that the universe was made up of over 70% dark energy, and
like 24ish% dark matter, which I though was pretty crazy.
-I actually did know that, awkward laugh.
-I also didn't know that um, dark matter was collisionless, so I thought that was pretty cool as well.
-Yeah, I just knew that we don't really know anything about it, yaknow.
-Yeah, just like kind of a mystery, but I would want to
like look into more of like why it's collisionless, like how, maybe.
The only way we can detect it is its silhouette, cause it's not observable.
And I also thought it was pretty cool that there's still radiation from the Big Bang, just radiating from everywhere in the universe right now, in the cosmic microwave background.
