The Astronomy Thread

Furry · Jul 24, 2015

Tuco_sl said:
Repost from science thread since this thread is more relevant:

Given that we just found out basic information about pluto, as a layman I am totally suspicious about any information we have about a planet that is 1400ly away. My understanding is that they look at how a star wobbles based on its orbiting planets, but I feel like without having a way to test those calculations and technology on anything other than our solar system, it's an unproven method.

Kepler detects planets by watching how bright a star is. Every time a planet passes in front of a star from our view, that star will get slightly dimmer. Kepler likely detected the star getting some fraciton of a percent dimmer in a few set intervals.

As for detecting atmospheres and compositions of extrasolar bodies, this can be tested within our solar system, but is done by exactly measuring essentially the color of light (spectroscopy).

An example of this being done in our solar system is with our first measurements of pluto. Occasionally planets will pass directly in front of a star, and this star will back light them. Using a lot of complex math and careful measurements of how the light of the star changes, we can determine a lot of things about the object in front of the star. With pluto, one of the specific discoveries we made when it passed directly in front of another star was that it was brownish in color. This is also the main reason the new horizons satelite turned back to watch pluto from the dark side, to watch the spectroscopy of the sun change against against the black body of our sun. The essential explination of how and why this works is the fact that light from stars tends to be very pure and perfect, so even incredibly small spikes caused by the interference of a small planet passing in front of them can be detected, especially when the existence and location of that planet in reference to the star is known.

iannis · Jul 24, 2015

Yeah, I'm a bit leery of those "A new earth-like discovered!"

It's not that a particularly mistrust their method. I don't. It's that it's easy to say something which is essentially irrelevant EVEN if it happens to be true.

And a lot of these earth-alikes are only earth-alike if you close your left eye and squint in just the right way. I don't have any idea about this one, but I have read about how they'll use that earth-alike in what amounts to a PR sort of fashion. Granted, it's hard to get people exited about extra-solar mapping... and granted no one has any idea of where the benefits to it might lie... and those benefits are delayed by generations at best... and I wouldn't ever go so far as to say it's a waste of time. That's not a subtle dig, I wouldn't because it's not. But you know, it's never really going to bepopularorexciting. It's a needful field... but if you want groupies be a rock star.

What they should do is aim SETI at that bitch, tbh.

Furry · Jul 24, 2015

Seti in general is colossal waste of time and resources. As for earth-like planets, generally speaking, earth has a lot of unusual features that make it fairly unique for a planet, and we aren't sure to what extent life could possibly flourish without these features, especially complex and highly evolved life.

For some perspective, just remember, that venus and mars would be detected as 'earth-like' planets by kepler, despite the fact that venus is incredibly inhospitable to life on many fundamental levels, and mars in general is not hospitable enough for complex life to evolve. There are so many factors that determine if a planet could support life, and more important if it could, how far that life could ever evolve. That said, we know some things that are very fundamentally important, and to some degrees those things CAN be detected with current technology.

What will likely happen is that telescopes will get pointed at this star during transits and people will monitor and very closely track spectral lines. If the influence of the planet tends to be a fairly simple and clean one, they might be able to establish that it has a simple atmosphere after averaging results for a decade or so, and PERHAPS even establish a vague color for the planet. With these two facts, we would likely be able to reasonably guess if the planet has a magnetosphere and the chance that it has oceans. Either one as a discovery would be incredible in its own right, the first one perhaps even more so. A planet with a fairly simple and non-ionized atmosphere at the proper distance from its home star would be an incredible candidate for the possibility of finding life, as this is considered probably one of if not the biggest indicator for the possibility of life that we could detect on extrasolar planets.

Spectroscopy in theory would allow us to directly detect biological compounds in the atmosphere in a way that would allow us to definitely prove life if it existed in a form we understood. Nothing is built with that capability currently, but we understand how it could be built, and computer aided interferometry has advanced incredibly over the past decade to bring such a creation to within the realm of what humanity could achieve. Basically, enough evidence and a few more targets to look at it, and maybe we'll even have the will to start making it happen in a decade. Unfortunately, none of this would ever likely translate into an actual visual understanding of the planet, so don't go expecting pictures of shit any time soon or likely ever in your life time.

Tuco · Jul 24, 2015

Thanks for the explanation.

LachiusTZ · Jul 24, 2015

"Rapid unscheduled disassembly" was what they called the first landing failure. Lol, those terms.

And yeah, the Kepler thing is neat, I think it's half broken now tho. But so is Hubble. NASA is just really good at making shit work.

"Failure is not an option."

Szlia · Jul 24, 2015

Silly questions: since exoplanets are detected by the dimming of the light that occurs when they travel between us and their star, doesn't it mean that 1) Planets that have very long years will take a very long time multiplied by three or four to be detected? 2a) Planets that don't have an orbit on the same plane as us will be undetected? 2b) Planets in our solar system are mostly on the same plane, is that roughly the same as the one of our galaxy? 2c) Is it expected to be the same for most exoplanets of stars in our galaxy?

Cad · Jul 24, 2015

Szlia_sl said:
Silly questions: since exoplanets are detected by the dimming of the light that occurs when they travel between us and their star, doesn't it mean that 1) Planets that have very long years will take a very long time multiplied by three or four to be detected? 2a) Planets that don't have an orbit on the same plane as us will be undetected? 2b) Planets in our solar system are mostly on the same plane, is that roughly the same as the one of our galaxy? 2c) Is it expected to be the same for most exoplanets of stars in our galaxy?

2b:

Are the planes of solar systems aligned with the plane of the Galaxy? (Intermediate) - Curious About Astronomy? Ask an Astronomer

They're oriented in all different directions. The size of a solar system is so much smaller than the size of the Galaxy, that the Galaxy's structure has no impact on the orientation of a solar system. What determines their orientations is the direction of the angular momentum that the system had when it formed, and that's pretty much random.

Our own solar system is tipped by about 63 degrees with respect to the plane of the galaxy.

Tripamang · Jul 24, 2015

Szlia_sl said:
Silly questions: since exoplanets are detected by the dimming of the light that occurs when they travel between us and their star, doesn't it mean that 1) Planets that have very long years will take a very long time multiplied by three or four to be detected? 2a) Planets that don't have an orbit on the same plane as us will be undetected? 2b) Planets in our solar system are mostly on the same plane, is that roughly the same as the one of our galaxy? 2c) Is it expected to be the same for most exoplanets of stars in our galaxy?

1. You've got it right. Kepler was designed to look at the same piece of sky for a long period of time looking for those blips. The only way to confirm a planet is to watch it pass in front of the star a few times. You need the first couple to determine a period and at least a third pass to see if it matches your prediction.

2a) Any planetary system not aligned with us isn't really visible by Kepler.

Cad answered b and c really.

Eomer · Jul 24, 2015

Further to 2a), while we can't see planets with the transit method if their axial plane is lined up with Earth, scientists can extrapolate Kepler's numbers to get an idea of what the frequency of particular types of planets and orbits are throughout the galaxy. The other thing to consider is that the transit method is NOT the only method for detecting planets. Most of the initial exoplanets that were discovered used a different technique, that basically measured the "wobble" of a star caused by orbiting planets. That particular method was extremely biased to finding huge, tidally locked Jupiter sized planets extremely close to their star. That's why initially planet searches weren't turning up much of any smaller planets further away from the star. And there's still really no method for detecting planets that are much further out from their star than Earth/Mars, other than sheer luck or extremely unique circumstances (gravitational lensing etc).

As far as Tuco's concerns about the transit method not being reliable, follow up observations with other instruments are conducted before a planet candidate is "confirmed":Kepler object of interest - Wikipedia, the free encyclopedia

To this point Kepler has identified around 4000 candidates, around 1000 of which have been confirmed. I don't think you'll find too many astronomers who have the same doubts that Tuco has.

khorum · Jul 24, 2015

LachiusTZ_sl said:
"Rapid unscheduled disassembly" was what they called the first landing failure. Lol, those terms.

yeah the RUD term was actually tweeted by Elon Musk to John Carmack lol.

SpaceX apparently has a seriously geeky culture that Musk actively cultivates to attract and retain a very specific kind of engineers and scientists.

It's expressed in everything from their procurement strategies to their retirement packages all the way to how they officially name their drone barges----if you've read Iain M. Banks' Culture series you'll get where their riffing the weird long names like"Of Course I Still Love You"and"Just Read The Instructions":

Kedwyn · Jul 24, 2015

Finding planets like that is pretty neat but it means nothing except to confirm what we already know that planets are plentiful.

What will be interesting is finding out if the conditions for life here are similar for other planets in the solar system and the galaxy. Just finding out if microbial life is common or was common in our solar system would be a huge discovery just as it would be interesting if earth was the only planet with any kind of indication of actual life in our solar system. We really need to get boots on the ground on mars and get exploring to start advancing that since Mars really is the best candidate to have had / have life. Its also close enough for actual humans to visit with current tech.

Earth has a ton of features that make it likely pretty rare and we have no idea how much that impacted evolution (likely a ton but we don't really know). The fact that our core is rather large compared to our planets size, that its still spinning and creating a magnetic field while places like mars are dead is obviously incredibly important. Our over sized moon was also likely clutch in evolution for many reasons and keeping us from impacts. Jupiter clearing out a path and not getting stuck near the sun was also huge, much less the other gas giants playing outfield. It will be interesting to see how much of that is actually necessary or a butterball bonus not too mention how much of that is repeated with any frequency in the galaxy.

The universe is obviously a big place and saying there is probably or even almost certainly another Earth out there is one thing, actually finding one or communicating with it in a meaningful way is entirely another. Ultimately it will be interesting to see if the Universe really is packed with life like in Star Trek or Star Wars or if its practically devoid of intelligent life due to scale and time frames of survivability that we end up being seeders of life instead of just exploring it.

We can start answering a key question about ourselves and the Universe. We likely will have the first answer in our lifetimes which is pretty fucking amazing. If we find life in any form existed on Mars or one of the moons or Jupiter / Saturn then its incredibly likely simple life is so common the Universe is shitting it out daily. Same might be true regardless if we find life or not in our solar system but it could also be the life is incredibly rare. We won't know until we put some serious effort into space exploration. Unfortunately with our love of war and other spending issues its not likely to get serious in our lifetimes.

Borzak · Jul 24, 2015

SETI got a $100 million donatoion from a Russian. Think of all the hookers and blow that would buy and have an actual impact.

Sterling · Jul 24, 2015

Yeah SETI is pretty far on the fringe of things.[email protected]/* <![CDATA[ */!function(t,e,r,n,c,a,p){try{t=document.currentScript||function(){for(t=document.getElementsByTagName('script'),e=t.length;e--

if(t[e].getAttribute('data-cfhash'))return t[e]}();if(t&&(c=t.previousSibling)){p=t.parentNode;if(a=c.getAttribute('data-cfemail')){for(e='',r='0x'+a.substr(0,2)|0,n=2;a.length-n;n+=2)e+='%'+('0'+('0x'+a.substr(n,2)^r).toString(16)).slice(-2);p.replaceChild(document.createTextNode(decodeURIComponent(e)),c)}p.removeChild(t)}}catch(u){}}()/* ]]> */was pretty big for awhile though. Lots of people datamining for them!

Eomer · Jul 24, 2015

Kedwyn_sl said:
Finding planets like that is pretty neat but it means nothing except to confirm what we already know that planets are plentiful.

Well no, actually, we didn't know that planets were plentiful until Kepler. That realization has literally only had truly scientific evidence to back it for about the past 5-6 years.

Kedwyn · Jul 24, 2015

Eomer_sl said:
Well no, actually, we didn't know that planets were plentiful until Kepler. That realization has literally only had truly scientific evidence to back it for about the past 5-6 years.

I'm not saying Kepler is useless. I'm just not excited over their recent announcement and the others like it over the years.

Dandain · Jul 24, 2015

I think its a rad announcement, its the first rocky planet around another G type star (like our sun) and within such small variance of size difference between the stars that conditions there would be more earthlike than anything else we have found yet. Most of the other verified rocky bodies in the habitable zones are around weaker less luminous stars than our own Sun. Without an image you have to imagine why this might be amazing. This planet is only 1400 light years from earth. The center of our galaxy is estimated around 27,000, we estimate stars beyond the center from like 70,000-100,000 light years to the other side of just our galaxy. I believe its a remarkable find given all the details. Its year is 20 days longer than our own.

edit:
I think this image gets me the most excited, just because it illustrates exactly how few of our confirmed habitable zone bodies are actually around starts as hot as our own sun. If you compare planet placement against both axis you will see that 452B lands remarkable close to Earth's position on the chart. Even with the 12 new small habitable zone candidates none of them are closer to the Earth/Sun relationship than 452B.

Sumi_sl · Jul 24, 2015

Arriving late to the thread, but I had this sent to me today and I think it is relevant with all the excitement about the habitable planets discovered orbiting stars in our own Milky Way.http://waitbutwhy.com/2014/05/fermi-paradox.html

LachiusTZ · Jul 24, 2015

I think that has been linked a few times.

We haven't geeked out hard on Fermi / Drake here, but they are on NASA space flight forums (if you feel like having a brain aneurysm check the EM drive thread there)

On a note of shit already posted, have we breached the NASA Orion project? Just saw it on:
Infographic: Whats the fastest ship in sci-fi history?
100g's, nuclear pulse? Friday night, and I'm being a big enough loser without looking that up. Lol

meStevo · Jul 24, 2015

Colorized unofficial image is amazing.

Daniel Fischer on Twitter: The rendition of Sputnik Planum by @NewHorizonsIMG - though some fantasy is involved - is the most spectacular yet:

Other awesome from today:Katie Mack on Twitter:

New flyover video.

Nice compilation of today's releases put together by the planetary society:http://planetary.s3.amazonaws.com/as...et-ver-4-1.png

Araxen · Jul 24, 2015

I know as a kid I always wanted to see what Pluto looked like and throughout the years I always used to here it'll be a boring chunk of frozen ice and today at 41 I'm glad all those fucks have been proven wrong. Pluto is turning out to be one of the most interesting planets in the system. It's moons are just as equally interesting. We can learn a lot from it's whole system. I really hope they re-classify planets because Pluto has it's own satellite system and I think that should qualify it as a planet. 5 moons? 1 or more satellites? Planet! Clearing it's own orbit is bullshit. It was the fucking Fox News of classifications and Scientists should definitely hold themselves to a better standard than Fox news.

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