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  • [INTRO ♫]

  • There’s something special about a good space telescope.

  • Think about it: Engineers spend years building and designing it,

  • scientists make their careers analyzing its data, and the rest of us

  • get to come together and marvel at how cool our universe is.

  • These are pretty amazing machines.

  • But like the humans who build them, space telescopes have a lifespan.

  • They get old and don’t work as well (also like us) and eventually,

  • the time comes to call it a day and let another mission take over.

  • And so yesterdayJanuary 30, 2020 — we had to say goodbye

  • to NASA’s Spitzer Space Telescope, which finally gets to retire

  • after spending more than 16 years revolutionizing infrared astronomy.

  • When looking into space, youll see things different

  • depending on what wavelengths of light you use.

  • The most energetic stuff out there, like black holes,

  • pumps out high-energy light with short wavelengths,

  • so it’s best observed by tuning your telescope to detect gamma and X-rays.

  • At the other end of the spectrum, all of space glows dimly

  • in long-wavelength light.

  • So to study that background radiation, youll need something

  • like a radio or microwave telescope.

  • But a ton of the universe lives in the in-between:

  • It’s full of objects too small or cold to produce shorter wavelengths,

  • and too big or warm to be seen well in the longest.

  • Things like planets and ancient galaxies (what astronomers call

  • the cold, the old, and the dusty”) those are best observed in infrared.

  • Because while many of them don’t give off much visible light,

  • they do give off some heat, which is basically what infrared light is.

  • That’s the kind of light Spitzer specialized in.

  • And we built it to be really good at detecting it.

  • The telescope had things like reflective materials and liquid helium,

  • which helped keep its instruments as cold as -267 degrees Celsius

  • only about three degrees warmer

  • than the background temperature of the universe.

  • Since colder objects emit less infrared light,

  • that meant Spitzer wouldn’t accidentally wash out its own observation

  • with its intrinsic glow.

  • So at the beginning of its mission, it was able to detect

  • the faintest emissions from really cold objects

  • and unreasonably far away objectslike super old galaxies.

  • In 2009, Spitzer’s coolant did run out as planned.

  • But after that, it entered itswarm phaseand kept working

  • at a cozy temperature of about -244 degrees Celsius.

  • Over those two phases and its 16 years, Spitzer gave us

  • tons of insight into the universe and led to some exciting discoveries.

  • Weve covered some of them before, like the oldest galaxy ever seen,

  • and the discovery of 5 of the 7 TRAPPIST-1 exoplanets.

  • That’s a planetary system around 40 light-years from here.

  • But there’s been a bunch of other cool stuff, too.

  • Like, in 2009, Spitzer discovered that Saturn has a giant ring

  • we didn’t know about because it’s basically invisible to us.

  • Its dust particles are so sparse that we can’t see them

  • with visible-light telescopes.

  • We can only see their infrared glow.

  • It’s called the Phoebe ring, because the moon Phoebe

  • orbits inside it and probably provides a lot of the ring’s material.

  • And it is ridiculously big.

  • From Earth, most of Saturn’s rings are really only visible with a telescope.

  • But if the Phoebe ring shined in visible light instead of infrared,

  • you could see it with the naked eye, stretching out wider than two full moons!

  • This finding didn’t just change our view of Saturn, either.

  • It also answered a question we’d been trying to answer for 300 years:

  • What’s going on with Iapetus?

  • Iapetus is one of Saturn’s moons near the Phoebe ring,

  • and it’s odd because its leading side is way darker than its other half.

  • The astronomer Cassini noticed this way back in the 1600s,

  • but nobody knew why it happened until we found the Phoebe ring.

  • After that, scientists proposed the moon’s coloring

  • is probably because it’s gathering dark Phoebe ring material

  • as it orbits, like a car grill gathering bug corpses on the highway.

  • Of course, Spitzer’s impact wasn’t just local:

  • It also gave us an unprecedented view of our galaxy

  • with things like an incredible, 360-degree map of the Milky Way.

  • Finalized in 2014 with over ten years of data, GLIMPSE360

  • shows a stretch of sky containing about half the stars in the galaxy,

  • which is way more than we can see in visible light.

  • This is because, in addition to all the stars and stuff out there,

  • there’s a bunch of gas that blocks visible light

  • but lets some infrared light through because of its longer wavelength.

  • In fact, this map lets us see clear through to the other side of the Milky Way,

  • and that’s allowed astronomers to map out the boundaries

  • of our galaxy with far more accuracy.

  • The data from this map was full of surprises, too:

  • It revealed new regions of star formation, and found a lot more carbon

  • in the galactic dust than we’d previously thought.

  • That helps us estimate how many stars are making carbon,

  • dying, and releasing it out into the void.

  • And considering that all life we know of requires carbon

  • knowing how much life-making material is out there is probably important.

  • As a whole, the map represents an incredible ten years of science,

  • capturing more than two million of Spitzer’s photos in a single image.

  • And it sets us up for the future!

  • Since it will also have some infrared capabilities,

  • the James Webb Space Telescope will be, in some ways, Spitzer’s successor.

  • So when it launches next year, fingers crossed,

  • astronomers will look to the Spitzer map to find

  • the most interesting and fruitful targets.

  • It’s always hard to say goodbye to missions, and this time is no exception.

  • But even though Spitzer has gone dark

  • and will spend the future just floating through space,

  • its data will light our way for years to come.

  • This episode of SciShow Space News is brought to you by the one,

  • the only, SR Foxley, who’s this week’s President of Space.

  • SR Foxley is one of our patrons on Patreon,

  • and those patrons help us keep diving into the news every week

  • along with everything else we do on this channel.

  • So thanks for being here, SR!

  • If you want to learn more about our patron community

  • (including things like our Discord server)

  • you can head over to Patreon.com/SciShow.

  • Our patrons make everything happen around here,

  • and we don’t know what we would do without them.

  • [OUTRO ♫]

[INTRO ♫]

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The Legacy of the Spitzer Space Telescope | SciShow News

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    林宜悉 posted on 2020/03/01
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