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We might be closer to figuring out how our solar system was born and NASA has two finalists for its next New Frontiers mission.

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Sources:
http://iopscience.iop.org/article/10.3847/1538-4357/aa992e/meta
https://news.uchicago.edu/article/2017/12/22/scientists-describe-how-solar-system-could-have-formed-bubble-around-giant-star
https://www.eurekalert.org/multimedia/pub/159267.php
http://www.popularmechanics.com/space/solar-system/a14486467/solar-system-formed-bubble-surrounding-hottest-stars/
https://www.hou.usra.edu/meetings/lpsc2017/pdf/1692.pdf
https://www.forbes.com/sites/briankoberlein/2017/12/27/our-sun-could-be-the-child-of-a-wolf/#6d1596744f53
http://www.skyandtelescope.com/astronomy-news/nasa-selects-finalists-next-new-frontiers-mission/
https://www.nasa.gov/press-release/nasa-invests-in-concept-development-for-missions-to-comet-saturn-moon-titan
http://dragonfly.jhuapl.edu/
http://www.jhuapl.edu/newscenter/pressreleases/2017/171221.asp
http://spacenews.com/nasa-selects-comet-and-titan-missions-as-new-frontiers-finalists/
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Images:
https://www.nasa.gov/mission_pages/chandra/images/wide-field-optical-image-of-supernova-1987a.html
https://www.nasa.gov/mission_pages/chandra/images/chandra-reveals-the-elementary-nature-of-cassiopeia-a.html
https://www.nasa.gov/image-feature/goddard/hubble-view-wolf-rayet-stars-intense-and-short-lived
https://www.nasa.gov/image-feature/goddard/2016/hubbles-blue-bubble
https://www.nasa.gov/jpl/pia18876/welcome-to-a-comet-from-lander-on-surface
https://www.nasa.gov/content/ten-years-ago-huygens-probe-lands-on-surface-of-titan
https://www.nasa.gov/multimedia/imagegallery/image_feature_318.html
https://www.nasa.gov/image-feature/jpl/5-peering-through-titans-haze
[ ♪ Intro ♪ ]With all the bigger cosmological mysteries like dark matter, dark energy, or what happensat the center of a black hole, you might think a question as local as “How was our solarsystem born?” was solved a long time ago.

Nope. But we might be a little closer to solving that puzzle, thanks to a new paper publishedin the Astrophysical Journal a couple of weeks ago.

Right now, the most widely-accepted hypothesis for how the Solar System came to be starts about 5 billion years ago with a nearby supernova, an exploding star. The shockwave from the explosion would have triggered the collapse of the large cloudof gas and dust that eventually became the Sun, planets, and all the other stuff in the Solar System — including us, eventually. But here’s the problem.

A supernova would also infuse our cloud with certain elements. They release aluminum-26, a type of aluminum with 13 neutrons, and iron-60, a type of ironwith 34 neutrons that you can only get from the explosion of a massive star. The thing is, the amount of aluminum-26 and iron-60 we’ve measured in our solar systemdoesn’t match what we should have gotten from a supernova.

Meteorites, which are a good way to measure the composition of the Solar System sincethey come from space, do have more aluminum-26 than what we find on average across the galaxy. But we’re low on iron-60. And a supernova would have injected both into our system — not just extra aluminum.

So in this new paper, a group of astronomers proposed a different idea: maybe the SolarSystem didn’t start with a supernova. Maybe it started with the wind-blown bubble surrounding a star 40-50 times the mass ofthe Sun — a type of star called a Wolf-Rayet star. Wolf-Rayet stars are basically the most massive and hottest-burning class of stars in the universe.

They’ve already exhausted all their hydrogen fuel, so they’re fusing heavier elementsinstead, and they have a really hard time holding themselves together. Their stellar wind, the gas streaming out from the star, is so strong that they loseabout 3 Earths’-worth of mass every year. The violence inside them forces heavier elements upward, too, so it’s not just a bunch ofhelium getting spewed out into space.

In fact, Wolf-Rayet stars release a lot of aluminum-26 … but not iron-60. Which sure sounds a lot like our solar system! These stars’ high-velocity winds and extreme temperatures create a huge bubble structure,including a shell of denser gas and dust that could eventually condense into stars.

Based on their computer simulations, the team estimates that anywhere between 1-16% of allSun-like stars could be formed in Wolf-Rayet star wind bubbles. Of course, we don’t know for sure. For one thing, this model assumes the meteorite data gives us a true representation of whatthe early solar system looked like, which we’ll never be able to know without a time machine.

This is a very new hypothesis, and until we have more research, most astronomers are probablygoing to stick with the supernova idea for now. But it does fit pretty nicely. While some astronomers are working on solving that 5 billion-year-old puzzle, others arecontinuing to explore the system we call home.

And now we’ve taken the next step in planning another mission! In late December, NASA announced two finalists for the next New Frontiers mission, which both sound awesome:One would sample a comet, and the other would send a nuclear-powered quadcopter to Titan,Saturn’s largest moon. Even if you’ve never heard of the New Frontiers mission program by name, you’ve probablyheard about at least one of the three missions that came out of it: New Horizons, Juno, and OSIRIS-REx.

The first of the two finalists bidding to be the fourth member of this special clubis the Comet Astrobiology Exploration Sample Return mission, or CAESAR. It would be a follow-up to the ESA’s Rosetta mission, which visited and landed the Philaeprobe on comet 67P/Churyumov-Gerasimenko in 2014. But CAESAR would go beyond that mission — it would actually collect a 100-gram sample ofthe comet’s surface and return it to Earth.

The Japanese space agency JAXA would use its experience from their asteroid sample returnmission Hayabusa to design CAESAR’s return capsule, which would return to Earth in November 2038. That might seem pretty far-off, but this is a whole new space mission we’re talking about. It takes a lot of planning!

If the Dragonfly mission is selected instead, it would arrive at Titan by 2034. Like 67P, we’ve landed on Titan before — with the Huygens probe, back in 2005. It even sent back pictures of the surface.

But this time we’d get to go flying. With Titan’s low gravity and super thick atmosphere, you could actually fly aroundby just strapping on wings and flapping your arms a bunch, which sounds like the best thing ever. But it’s tough to send an astronaut all the way out there when we haven’t even gottenone to Mars yet, so a quadcopter is the next best thing.

Because of all those clouds and Titan’s distance from the Sun, solar power isn’t an option. So, like a certain famous DeLorean time machine from the 1980s, it would be powered by plutonium. Legally acquired, though.

And the waste heat produced by the generator would be used to keep the electronics fromgetting too cold. Dragonfly would land at a bunch of different geologic sites covering hundreds of kilometers,and use a drill to sample pieces of Titan’s surface and analyze its composition. That includes hunting for chemical signatures that could indicate the presence of life.

It would also look for any possible seismic activity and profile atmospheric conditions,giving us a better sense of what life would be like on this weird alien moon where itrains methane instead of water. The teams working on both projects will receive funding through the end of 2018 to keep developingthem, and NASA will select the winner in spring of 2019. So I guess we’ll just have to stay tuned to find out which project gets the go-ahead.

So make sure to hit that red subscribe button so you get all the latest Space News. In the meantime, thanks for watching this episode of SciShow Space News, and if you’reinterested in learning more about Titan, you can check out our video about all the weirdness over there.[ ♪ Outro ♪ ]