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  • [♪ INTRO]

  • Even though it can sound all futuristic and sci-fi,

  • sometimes, astronomy is just about studying stuff that's really old.

  • And the older it is, the cooler it gets.

  • On Monday, astronomers published a paper in the journal Nature Astronomy announcing that

  • they've found one of the oldest galaxies we've ever seen: a galaxy named G09 83808.

  • Which, somehow, is the shortened version of its name.

  • It formed 12.8 billion years ago, making it less than a billion years younger

  • than the universe itself.

  • It's what astronomers call a dusty, star-forming galaxy,

  • or one that produces hundreds of stars each year.

  • And it's the third-oldest one we've ever found, behind ones that formed

  • 880 and 760 million years after the Big Bang.

  • The galaxy was first spotted in 2012 by the orbiting Herschel Space Observatory,

  • but it wasn't powerful enough to see it clearly.

  • So the real star of this story is the Large Millimeter Telescope, or LMT, in Mexico,

  • which started observing the galaxy in 2014.

  • The LMT was designed to study the farthest, faintest objects in the universe,

  • including galaxies like this one.

  • Like other telescopes, it calculates the object's distance using its redshift,

  • or how red its light looks because of the universe's expansion.

  • See, as the universe expands, the light from distant galaxies gets stretched, too.

  • That gives the light a longer wavelength, which means that by the time we see it,

  • it's been shifted toward the redder, longer side of the spectrum.

  • By measuring how much the light has shifted, whether it's white light that looks red,

  • or radio waves with a longer wavelength than normal,

  • scientists can get a good idea how far away the object is.

  • Even though telescopes like the LMT are powerful,

  • they aren't strong enough to observe galaxies this far away on their own.

  • To find this one, scientists got a little help.

  • But it wasn't from another telescope, it was from an effect known as gravitational lensing.

  • Conveniently, there was another large galaxy between us and 83808.

  • It was in just the right spot, and was so massive that the light bent around it,

  • magnifying 83808 and making it look about 10 times brighter than normal.

  • Studying ancient galaxies like this can teach us more about the timeline of the universe.

  • Astronomers think galaxies started forming between 200 million and a billion years

  • after the Big Bang, and because of its age, this discovery supports that idea.

  • And maybe the coolest part about all of this is that even though the LMT

  • is helping us make discoveries, it isn't even at full capacity yet!

  • At first, it was only about 30 meters in diameter, but now,

  • it's fully-built and is 50 meters across, and will be ready for more science this January.

  • So, pretty soon, we'll be checking out even more galaxies

  • from a long, long time ago, far, far away.

  • Closer to home, another team of astronomers

  • has developed a new method for finding habitable exoplanets.

  • And their strategy, published in the journal Scientific Reports last week,

  • could save astronomers a lot of time.

  • A habitable exoplanet can refer to a lot of things,

  • including planets in the right orbit around their stars, or ones with liquid water.

  • But this method specifically searches for planets with an atmosphere we could breathe.

  • Normally, scientists hunt for habitable exoplanets by looking for molecules like oxygen and methane,

  • which are made by plants and animals here on Earth.

  • Unfortunately, that method can take days of observation,

  • which isn't always possible when everyone wants a piece of those fancy space telescopes.

  • This new method finds habitable planets by searching for the byproducts of stellar storms.

  • And instead of taking days, it only takes a few hours.

  • So far, we haven't tested it out on any exoplanets,

  • but we know the idea works on Earth.

  • Plenty of stars, including our sun, have the occasional storm,

  • where they release high-energy particles into space.

  • On Earth, you often hear about them causing the northern and southern lights.

  • But those storms also kickstart a chemical reaction in our atmosphere.

  • The particles react with the atmosphere's nitrogen and oxygen to create three molecules:

  • hydroxyl, or hydrogen and oxygen atoms bonded together; nitric oxide,

  • which is one nitrogen and oxygen; and plain old molecular oxygen.

  • These molecules aren't a definite sign of an Earth-like atmosphere, but they're so

  • important that the authors of the paper call thematmospheric beacons of life.”

  • And we can detect them with space telescopes.

  • We're most familiar with the reaction on Earth, but it isn't limited to us:

  • Any planet with a lot of nitrogen and oxygen in its atmosphere

  • would react this way if it got hit with a stellar storm.

  • So, if we scan for atmospheric beacons around planets with stormy stars,

  • we could find habitable planets with an atmosphere like Earth's.

  • We'd still be limited to planets we could see directly, but scientists estimate we'd

  • be able to find beacons with a telescope smaller than the Hubble Space Telescope.

  • And if we did, we could use newer telescopes, like the James Webb Space Telescope,

  • which will launch in 2019, to take a closer look at the planets with those beacons.

  • Researchers are always on the hunt for new, habitable exoplanets,

  • so this might be the start of an exciting new chapter in astronomy.

  • Now, those beacon molecules could still exist around a planet without an Earth-like atmosphere,

  • so we'll need to be sure we know what else could cause those signals too,

  • like volcanoes, before we jump to conclusions.

  • But since this method takes less time, it will let us scan a lot more planets.

  • So maybe someday, besides having more old galaxies to study,

  • researchers might also have a whole long list of habitable exoplanets, too.

  • Thank you for watching this episode of SciShow Space!

  • And a big thanks to our patrons on Patreon who make SciShow Space exist,

  • and make it free and available to everyone.

  • Thank you!

  • If you'd like to help us keep making episodes like this, you can go to patreon.com/scishow.

  • [♪ OUTRO]

[♪ INTRO]

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B2 habitable exoplanets atmosphere telescope oxygen space

We Found One of the Oldest Galaxies Ever!

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    林宜悉 posted on 2020/04/04
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