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Astronomers use x-rays to study stuff in space all the time.
They’re a fairly standard part of the toolkit.
But this week, in a paper published in Nature Astronomy,
an international team used a new strategy in order to observe a very distant,
very young galaxy undergoing rapid star formation.
Basically, they used a galaxy cluster to look at the x-rays emitted by a galaxy behind it.
And they did so in order to look into the very, very distant cosmic past.
Massive bodies like galaxies have gravity, and gravity can bend light.
The bigger the body, the bigger the light bending,
and as the light bends, its source appears magnified to us.
It’s like the lens in a telescope, except instead of being glass in a tube,
it’s something like a black hole in space.
Also like a telescope, it helps us see things farther away than we normally could.
This process is called gravitational lensing, and it works with all wavelengths of light.
Until now, however, lensing studies have mostly been done
using lower-energy wavelengths, like infrared and microwave.
But really energetic phenomena, like star and galaxy formation,
emit really energetic light, like x-rays.
Which was just the ticket for observing this sprightly young galaxy.
The light we can see from this galaxy is about 9.4 billion years old,
so these observations represent a galaxy pretty early in the universe’s life.
The newly-formed stars there were mostly low mass and low metallicity,
meaning there were very few elements present that are heavier than helium.
But the fact that this galaxy is visible in x-ray light means that
there’s got to be x-ray sources there, and that’s not these low-mass stars.
You gotta get real big and real energetic before you emit x-rays like that.
When galaxies are young and forming lots of stars,
some of those stars will form high mass x-ray binaries, or HMXBs,
two big stars orbiting each other that emit a bunch of x-ray light.
Unlike their low-mass siblings, these star pairs are huge and short-lived.
Usually, one ends up dying, collapsing into a neutron star or maybe even a black hole,
and then starts siphoning off its partner’s atmosphere.
All this produces huge x-ray jets and shockwaves that can affect the whole galaxy,
and even stuff outside of the galaxy, in ways we don’t yet fully understand.
For instance, we don’t know for sure how related star formation is to the formation of HMXBs.
Maybe the shockwaves help trigger star formation.
HMXBs also may help us answer another big question in cosmology.
See, the intergalactic medium, that is, the gas between galaxies,
has an electric charge, and we do not know why.
It’s basically a hot, charged plasma now, but observations of very distant
and therefore very old targets suggest that it used to be totally neutral.
So where did the charge come from?
Well, those x-ray jets would definitely help!
X-rays are a form of ionizing radiation, meaning they can totally charge gas.
That means enough galaxies with enough HMXBs could do the trick.
Or, at least could be part of the trick.
But either way, more studies of HMXBs will be
a fascinating window into the early universe and the formation of the first galaxies.
Much closer to home, after two years of delays,
NASA got its ICON mission off the ground last Thursday.
ICON is gonna orbit the Earth to study
the upper-most, charged part of our atmosphere, called the ionosphere.
It’s where low-earth orbit is, so most of our satellites, including the ISS, live there.
When solar winds interact with the ionosphere, you can get beautiful auroras,
and you can also get, like, satellite-damage.
A bad enough solar storm could knock out GPS communications and be super dangerous to astronauts,
so NASA is pretty motivated to figure out how to protect against that.
Until recently, we thought that the ionosphere was only affected by solar winds,
but it turns out that storms on Earth can affect it too.
Extreme storms like hurricanes can produce turbulence that can churn up the atmosphere
all the way to the ionosphere, creating really dense patches of plasma
that we definitely don’t want our satellites to go through.
But even less dramatic weather, like sustained winds, can produce turbulence in the ionosphere.
So ICON is going to study the ionosphere to better understand
the connection between the sun, the ground, and the sky.
And ICON’s coolness isn’t limited to the satellite itself.
The rocket that carried it has a very neat little launch procedure.
Called Pegasus XL, it gets launched from the air.
It’s carried a little under 12,000 meters into the air by a huge plane, then it is let go,
so it free-falls for about five seconds. And then it launches!
The idea is that, at that altitude, there’s less friction from the atmosphere,
so the rocket doesn’t need as much fuel.
And you don’t need a fancy launch pad for it, just a runway.
Of course, you still need jet fuel in the plane that gets it up there, so there’s a tradeoff,
but it’s a launch process that the Pegasus rockets have used since the early 90s.
And it looks cool and it gets the science done, so win-win.
Thanks for watching SciShow Space, which is a Complexly production.
And it is an exciting week here at Complexly, because we’re trying something totally new.
Actually, three somethings. It’s Complexly Pilot season!
We’re launching three brand new shows, each on their own channel.
Each show will run for 3 episodes for 3 weeks,
and then we will decide if we want any of those shows to continue on.
There’s History Pop, which will dive into the intersection of history and pop culture,
and will air on Tuesdays through the end of October.
Stories Retold, an all-ages series about fables and fairy tales,
will go out on Wednesdays through the end of October.
And Hashed Out, will help viewers navigate the media landscape from journalism to Twitter.
Posting Thursdays through, you guessed it, the end of October.
We love all of these ideas, but we don’t have the bandwidth
to make all of them happen at the same time,
so we would love your feedback on what you think we should continue.
Check ‘em out and share your thoughts.
Links are all in the description. Thanks!
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