Hello Space Fans and welcome to another edition of Space Fan News.
This week, astronomers from the Sloan Digital Sky Survey have created the largest map of
the universe so far; also, scientists trying to understand the habitability of the closest
exoplanet to us, promima b have already made some small progress towards finding out if
life can exist there or not; and some updates on launches and spacewalks on the ISS.
It pretty much goes without saying that the universe is pretty big, and what we know about
it is evolving and growing all the time.
Just a couple of years ago, I used to say there were about 100 billion galaxies in the
universe - all of my videos made at the time said that too.
Then Hubble came along and did what it does and said, actually, wait a minute there's
like 10 times more galaxies than that.
So now I gotta say there's a thousand billion or a trillion galaxies out there.
That's a lot of stuff and that's only counting what we can see, there's also dark
matter and dark energy that makes up even more of the universe that we can't see at
all.
So the more we keep looking up, the more we find out and this week astronomers have made
a map of the universe based on quasar locations, and what it shows is that it appears our standard
model of the universe is on track.
The standard model of the universe is based on Einstein's General Theory of Relativity
and it does a good job of predicting and matching our observations, even though we don't really
understand everything we see.
I mean, relativity describes the large-scale universe just great, but it includes things
like dark matter and dark energy, which are components of the universe we don't really
understand all that much.
So let's get back to the map these guys made.
Astronomers using a two and a half meter telescope at Apache Point in the sacramento mountains
of New Mexico which was equipped with a set of spectrographs called eBOSS, measured the
redshifts of more than 147,000 quasars and these redshifts allowed astronomers to get
their three-dimensional locations in the universe out to a time when the universe was between
three and seven billion years old.
These were times in the universe way before the Earth even existed.
They measured quasars because they are very bright, they are the brightest things in the
universe so seeing them was relatively easy.
Remember quasars are very high energy sources powered by supermassive black holes at the
centers of galaxies.
To make the map, astronomers looked the area of sky accessible from from New Mexico for
two years to get the spectra of the 147,000 quasars.
Once they had those, they then needed to compare their locations with the standard model I
was telling you about.
And the standard model includes this really confusing thing called baryon acoustic ocscillations,
or BAO's.
Now if you don't get this don't feel bad, I don't fully understand what BAO's are
either but when it comes to the large-scale structure of the universe, they are important
because they helped sculpt the cosmic web of galaxies we see today, and if our standard
model is right, then BAO's were the starting point for where most galaxies in the universe
ended up.
As I understand it, BAO's are sound waves of the universe created during the big bang.
Those sound waves were travelling through the hot and dense early universe like crazy.
Then about 380,000 years after the big bang, conditions changed suddenly and the sound
waves became frozen in place and we can still see them in the cosmic microwave background.
There's a lot more to this and of course I'm being overly simplistic, but if the
map these guys in New Mexico made was going to be right, then the locations of all those
147,000 quasars better match up with where the BAO imprints say they should be.
And the good news is that they do.
Astronomers from this study say that what they found confirms our standard model that's
been built up over the last twenty years and Einstein.
Which you know, is good, because one less thing.
This survey, called eBOSS, is still continuing.
As astronomers with eBOSS observe more quasars and nearby galaxies, the size of their map
will continue to increase.
And after it's over, a new generation of sky surveys will begin, including the Dark
Energy Spectroscopic Instrument (DESI) and the European Space Agency Euclid satellite
mission.
These surveys will increase the fidelity of the maps by a factor of ten compared with
eBOSS, revealing the Universe and Dark Energy in unprecedented detail.
Next, remember how excited we got when we found out that the closest star system to
us, Proxima Centauri, had a planet around it?
Then remember it got better when they said that the exoplanet was in the habitable zone
around the star?
It was really cool to think about that the closest star system to Earth, a little over
4 light years away, could potentially harbor life.
The thing is, we really don't know any else about the planet.
We know it's there, and we know that if any water is there, it could be liquid.
That's it.
Nothing else.
Nada.
So what we need is more data, lots of it from bigger telescopes like JWST, But not having
those observations hasn't stopped astronomers from running simulations based on what we
do know to see what might be possible.
A team of astrophysics and meteorology experts from the University of Exeter have undertaken
new research to explore the potential climate of the planet, towards the longer term goal
of revealing whether it has the potential to support life.
What they've done is they took one of the most accurate and state-of-the-art models
that meteorologists use here on Earth to predict what the next seven days are going to be like
and ran them using a variety of parameters on Proxima b to see what things might be like
there.
Using the state-of-the-art Met Office Unified Model, which has been successfully used to
study the Earth's climate for several decades, they started by saying OK, what if Proxima
b has an atmosphere like Earth, what would happen?
They also used a simpler atmospheric model that had just traces of carbon dioxide, oh,
and they played around with the orbit as well - including looking at a tidally-locked orbit
and an orbit with a 3:2 resonance like Mercury has.
A 3:2 resonance means that the planet rotates three times on its axis for every two orbits
around the sun.
There is one big difference of proxima b from Earth, and that is it's star is way different
from our sun and emits a lot of infrared energy.
These frequencies of light interact much more strongly with water vapour and carbon dioxide
in the atmosphere which affects the climate that emerges in our model.
So by playing around with all these parameters they found that that both the tidally-locked
and 3:2 resonance configurations result in regions of the planet able to host liquid
water.
However, the 3:2 resonance example resulted in more substantial areas of the planet falling
within this temperature range.
Additionally, they found that the expectation of an eccentric orbit, could lead to a further
increase in the "habitability" of this world.
So while this exercise was probably fun, we really need more information before going
too far with our hopes of habitablilty.
Still, simulations like this at least keep the hope alive that perhaps there might actually
be life on the closest exoplanet to the Earth.
Finally, thanks to Chris Marshall, we have more updates on launches and spacewalks.
I feel like with Chris, SFN has it's own space launch editor.
Check it out!
SpaceX continued its busy launch campaign this week with the successful delivery to
orbit of the Inmarsat 5 F4 communications satellite.
The payload was originally planned to be launched using the companies Falcon Heavy Rocket due
to the weight of the satellite.
However, with the upgrades to the Falcon 9 over the years it is was powerful enough to
perform the launch in expendable mode.
To date this is the heaviest payload SpaceX has ever launched, this meant that SpaceX
didn't attempt a landing instead letting the first stage splash down in the Atlantic
Ocean after separation.
SpaceX has another launch planned for June 1 st to deliver another Dragon vehicle to
the International Space Station.
On May 12th Astronauts Peggy Whitson and Jack Fischer stepped outside the International
Space
Station for a four hour 13-minute spacewalk during which time they completed four primary
tasks and one additional.
The spacewalk was originally planned to be approximately six and half hours, however
during the suit up procedures inside the station and small water leak was detected in Jack's
Service and Cooling Umbilical or SCU which provides power, water and air to the suits
while the astronauts are inside the station.
Mission controlled decided to proceed with the walk and the two shared Peggy's SCU
while completing suit up.
This meant the suits were running on battery power while inside and therefore reduced time
available for the walk.
This was Peggy's ninth spacewalk for a total time of 57 hours, 35 minutes and Jack's
first and was the 200 th spacewalk at the ISS for a total time of 1247 hours 55 minutes.
Well that's it for this week space fans, I'll be away next week so no episode but
I'll be back the following Friday.
SFN is made possible by the support of patreon patrons, please consider contributing a small
amount if you find this video series useful.
Thanks to all of you for watching and as always, Keep Looking Up!
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