The Astronomy Thread

Hekotat

Hekotat

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Not sure if this is the best place for this, but it's Commander Chris Hadfield playing David Bowie's Space Oddity on the ISS before he came back to earth. Shit is really well done.

 
S

Sugarhigh_sl

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Commander Chris Hadfields use of social media (twitter/youtube/reddit) has been phenomenal... i swear this man has generated more interest in space than anything done by NASA/CSA in the last 10 years easily
 
Hekotat

Hekotat

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Yeah his twitter stuff was an incredible leap in bringing interest to space exploration etc, all the interaction with people through videos was awesome. Sucks he couldn't just stay up there an promote it more.
 
Alex

Alex

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Kepler findings have been some of my favorite announcements in the science community. This really is a bummer to hear.
 
Furry

Furry

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Yea. Kepler has been one of the better things we've put into space. I know they're working on a replacement, but a few years of being blind will definitely be a missed opportunity.
 
Eomer

Eomer

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It's not just that we're blind for a few years. It's that to confirm Earth-like planets around Sun-like stars, it was imperative that it last another year or two. It needs to see at least 3 transits before it can confirm a planet candidate, and it will fall short of that for Earth-like planets/orbits.
 
Furry

Furry

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Eomer_sl said:
It's not just that we're blind for a few years. It's that to confirm Earth-like planets around Sun-like stars, it was imperative that it last another year or two. It needs to see at least 3 transits before it can confirm a planet candidate, and it will fall short of that for Earth-like planets/orbits.
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Yea, its definitely a setback, but luckily the work its already done is saved, so we dont need to start from scratch when the next one goes up.
 
Eomer

Eomer

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Well no, all the stars that it was looking at will have to be looked at again to find planets with longer orbital periods.
 
Szlia

Szlia

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What is the expected range of orbital period for planets with liquid water? Running four years, Kepler would have caught Mercury, Venus, Earth and two occurrences of Mars (10% chance of 3 occurrences) in our solar system. Sounds pretty good to me!
 
Cybsled

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It requires long term observation to ensure that false positives can be ruled out. For instance, if you're looking at a star and see something that could represent a planet, you need to make sure that you detect it again (ie, it's orbiting vs. just some random passer by). This is part of the reason why it has been easier to find the "freak" planets that orbit the sun at a very fast rate.
 
Eomer

Eomer

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Szlia_sl said:
What is the expected range of orbital period for planets with liquid water? Running four years, Kepler would have caught Mercury, Venus, Earth and two occurrences of Mars (10% chance of 3 occurrences) in our solar system. Sounds pretty good to me!
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Totally dependent on the type of star it is orbiting. And my understanding is that it was just short of the time required to observe a planet like Earth orbiting a Sun-like star three times, but perhaps I'm wrong on that. From the New Scientist article I posted before:

Still, if Kepler cannot be brought back into action, the timing will be tragic for scientists hoping to realise the mission's primary goal: determining what fraction of sun-like stars host Earth-sized planets with temperatures favourable for life.

Astronomers need to see at least three transits to confirm a signal as an orbiting planet. That means planets farther from their stars, in the habitable "Goldilocks zone" - in which a planet's surface temperature is just right for liquid water to exist - will take longer to find. Kepler needs a few more years' worth of data to see planets around sun-like stars with orbits that last longer than 200 days, says exoplanet researcher Sara Seager of the Massachusetts Institute of Technology.

"It will mean that the mission won't confirm as many small planets in the habitable zone as had been hoped," says Fabrycky. "It's a real loss."
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Near as I can tell, it's been up there and observing for 4 years, with some windows where it was in safe mode. So I'm not sure why exactly it was short on time.
 
iannis

iannis

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There's a lot to look at. Billions and Billions, man!

Plus my geometry might be shitting with my head, but the further away you look the faster (to the observer) the transit would be, right? So you have to guess that there's a transit there to begin with and then you have to stare at the star for months to even have a chance at catching it. And if the orbital plane is off from our own that makes it even more difficult/unlikely.

To a layman like myself it seems like the odds of finding specific transits would be vanishingly small, while the odds of just finding "ooooh, a transit!" would still be unlikely, but more reasonable.
 
Furry

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You are correct about orbital planes. For every planet we find, there are likely THOUSANDS of planets with orbital planes that make them undetectable by kepler or any future similar project.

You are incorrect about transit times. Thats more a function of how big a star is and how fast the planet orbits. How far away the target sun is will have no noticeable effect.

Generally. If a planet transits once, it will transit again. Other methods can detect planets that are not on the orbital planet, but these methods are generally very difficult and time consuming in comparison. Kepler was exceptional for its ability to mass canvas such a large area so quickly. The successor to kepler will be far more powerful and be able to survey a much larger area with greater accuracy, making detection of life-supporting candidates much better. Kepler was a stunning success and we definitely need to get a new hotrod version up there asap. Optics have advanced an amazing amount since the first one was launched, and kepler has showed us that there is a lot to find.
 
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