The Astronomy Thread

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Mjolnir
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Re: The Astronomy Thread

Post by Mjolnir »

GeoModder wrote:
Mjolnir wrote:Ammonia was thought to be a major component of Earth's atmosphere early on, but more modern models lack it. Ammonia's relatively reactive and unstable (as is methane, also considered a candidate), so N2, CO2, CO, and H2O is a more likely composition, with a good bit of SO2 and H2S from volcanism...basically a wetter Venus. Early enough, there would have been some H2 as well. The methane/ammonia-rich atmospheres of the original Miller-Urey experiment are not likely (though the results are pretty much the same as long as there's not much free oxygen).
Do you happen to know the 'frostline' for ammonia in the Solar System? In the current era that is?
I've looked for that kind of information before, and not had any more luck than icekatze.

It's notable that Titan has a substantial amount of methane in its atmosphere, enough for a hydrological cycle, but pretty much no ammonia...but a great deal of nitrogen, which probably came from ammonia. And ammonia ices were found on Charon, though they may have been deposited by an impactor. It's also not just a matter of ammonia being stable...ammonia is highly miscible with water, while methane is not, so it may tend to stay locked up in water ices. That would make it relatively easy to miss or underestimate, especially if it gets destroyed in or escapes from surface ices.

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GeoModder
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Re: The Astronomy Thread

Post by GeoModder »

Miss or underestimate (ammonia)... reminds me of this expression: There's only minite amounts of it, but what is minite when you consider the atmosphere of a gas giant (Jupiter and Saturn). :)
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icekatze
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Re: The Astronomy Thread

Post by icekatze »

hi hi

Here's an interesting one: Most Luminous Supernova Ever Recorded.

ASAS-SN-15lh, at its peak, put out 50 times more light than the entire Milky Way galaxy, which is twice as bright as the previous record holder.

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Arioch
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Re: The Astronomy Thread

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Suederwind
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Re: The Astronomy Thread

Post by Suederwind »

EVIDENCE FOR A DISTANT GIANT PLANET IN THE SOLAR SYSTEM

Sorry for the capslock, just copied it. Have read about that on a German news site and although its one of many theories about such a 9th (or 10th) planet, its the first one I have heard in a while.
Forum RP: Cydonia Rising
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Arioch
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Re: The Astronomy Thread

Post by Arioch »

I personally think they're trying to see patterns in what are essentially random numbers. It's really hard to believe that a >= 10 Earth-mass planet in our system could still remain undetected. People spent a lot of time looking for Nemesis, and all they found were Kuiper Belt objects.

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icekatze
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Re: The Astronomy Thread

Post by icekatze »

hi hi

Sure it is possible that there's a large planet out beyond Neptune, but I'm not going to hold my breath on this one. Finding a large planet out there might help support the nice model of solar system formation, but WISE did a pretty comprehensive search for large bodies in the outer solar system and didn't find anything.

If they do find solid evidence of something, it will surprise a lot of people.

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Re: The Astronomy Thread

Post by Jack »

Emphasis during the observatory to search for alleged planet.

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Re: The Astronomy Thread

Post by Jack »

http://arxiv.org/abs/1512.02652
A new submm source within a few arcseconds of α Centauri: ALMA discovers the most distant object of the solar system

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icekatze
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Re: The Astronomy Thread

Post by icekatze »

hi hi

In my view, Mike Brown just gets less and less credible, every time I read his work. He unambiguously slams the ALMA results, and then, just a couple weeks later, claims to have found his own massive planet in the outer solar system. And without any confirmation of its existence, goes on to call it the most planet like planet there is, an ex post facto justification for his own definition of what makes a planet.

fredgiblet
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Re: The Astronomy Thread

Post by fredgiblet »

http://gizmodo.com/holy-shit-scientists ... 1755465297

According to this scientists have, for the first time, confirmed the existence of gravitational waves. Gravity generators when?

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icekatze
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Re: The Astronomy Thread

Post by icekatze »

hi hi

I had heard about the LIGO rumors a little while ago, and I'm hoping those results can be independently confirmed. Although, as super important as this discovery is, I doubt we're any closer to making gravity generators. This confirms what we already suspected, so it probably won't change everything.

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Arioch
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Re: The Astronomy Thread

Post by Arioch »

Gravitational waves are so well-established in theory that I think the shocking development would have been if the experiment had failed to detect them.

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dragoongfa
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Re: The Astronomy Thread

Post by dragoongfa »

Correct me if I am wrong but all I got from the development is that they actually 'proved' that the gravitational waves travel with a certain speed which disproves the neutonian belief that gravity is instantaneous.

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Arioch
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Re: The Astronomy Thread

Post by Arioch »

Not exactly. Gravity waves are predicted by Einstein's model of gravity, which is about a hundred years old at this point. Because gravity waves are so hard to detect, we haven't been able to directly demonstrate that part of the theory until now. However, gravity waves have already been indirectly demonstrated by the rate at which close-orbiting massive stars spiral in towards each other. So while this is an important scientific finding, and these gravity wave detectors can be used to tell us about black holes and other very massive objects, this is not a "discovery" or a new development, just a direct confirmation of what General Relativity tells us about how gravity works.

PBS Space Time has good videos explaining the finding and about gravitational waves in general.


Absalom
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Re: The Astronomy Thread

Post by Absalom »

icekatze wrote:Although, as super important as this discovery is, I doubt we're any closer to making gravity generators.
Yeah, I suspect that the Higgs is what moved that needle, not Gravity Waves. We already had spectroscopic evidence from a case of gravitational lensing + red-shift-difference from a rapidly spinning red dwarf to demonstrate that moving masses can gravitationally transmit energy.

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icekatze
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Re: The Astronomy Thread

Post by icekatze »

hi hi

This one is pretty exciting: 1.3 to 3 earth mass planet found orbiting Proxima Centauri in the Goldilocks zone.

I heard some rumors about this one a few days ago, but it sounds like Kepler went ahead and backed up the earlier observations, so there's a pretty strong chance that it's the real deal.

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GeoModder
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Re: The Astronomy Thread

Post by GeoModder »

Unfortunately Proxima Centauri is quite an active flare star. :(
And what happened with the Alpha Centauri Bb claim back in 2012? The article jumps from Epsilon Eridani b to Proxima without even mentioning it!
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Arioch
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Re: The Astronomy Thread

Post by Arioch »

GeoModder wrote:And what happened with the Alpha Centauri Bb claim back in 2012? The article jumps from Epsilon Eridani b to Proxima without even mentioning it!
As I understand it, the methods used to detect αCenBb were called into question and then essentially demonstrated as inadequate; even the discoverer agreed that it probably doesn't exist.

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icekatze
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Re: The Astronomy Thread

Post by icekatze »

hi hi

Blarg... I misread the article. Kepler wasn't the team that provided the second opinion, rather it was a group of Earth bound telescopes. Talk about an embarrassing reading comprehension fail. :cry:

Still, it does seem like the data is pretty robust.

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