The Astronomy Thread

Tripamang

Tripamang

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Urlithani_sl said:
From what I understand, photosynthesis is the only natural occurrence that creates O2, since O2 usually bonds with carbon to make CO2. (I may be butchering this statement with my ignorance).

Would finding a planet with a rich oxygen atmosphere draw a probable conclusion of the presence of life, even simple life such as cyanobacteria that oxygenated our planet billions of years ago, or would it take more than that to get excited?
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The problem with detecting oxygen is that water vapor in the atmosphere when hit with light, will break apart into oxygen and hydrogen. So we can't necessarily use it as a possible marker as life as there is a natural process that would make it detectable.

Oxygen In Exoplanet Atmospheres Could Fool Search For Life - Astrobiology Magazine
 
Cybsled

Cybsled

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Tuco_sl said:
As someone who knows little about organic chemistry, id be super interested if we discovered a planet teeming with silicone/ ammonia based life instead of carbon / water
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Titan would be the closest place to look ;P They're sending a boat/submarine probe there eventually.
 
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Kedwyn

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The lander we sent found a dry place. Hopefully they actually find the hydrocarbon seas next time that they predicted.
 
AngryGerbil

AngryGerbil

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Tuco_sl said:
As someone who knows little about organic chemistry, id be super interested if we discovered a planet teeming with silicone/ ammonia based life instead of carbon / water
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Tocu, with your background in chemistry, is it correct to say that although other life forms may use silicone or something else as its Lincoln Logs instead of carbon, it will still always need liquid water? Water being the universal solute, necessary for osmosis, and the only substance that is less dense in its frozen state, etc etc?

If so, then looking for organic molecules is too narrow of a search. The life we are looking for may not even use carbon, and carbon itselfisorganic chemistry. We already know many forms of life that don't need oxygen so that's also too narrow. The first thing we need to find is liquid water. Yes? No?

How would ammonia replace water? I guess that's my question.
 
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Grimey

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AngryGerbil_sl said:
Tocu, with your background in chemistry, is it correct to say that although other life forms may use silicone or something else as its Lincoln Logs instead of carbon, it will still always need liquid water? Water being the universal solute, necessary for osmosis, and the only substance that is less dense in its frozen state, etc etc?

If so, then looking for organic molecules is too narrow of a search. The life we are looking for may not even use carbon, and carbon itselfisorganic chemistry. We already know many forms of life that don't need oxygen so that's also too narrow. The first thing we need to find is liquid water. Yes? No?

How would ammonia replace water? I guess that's my question.
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Water serves a few main functions: as a polar solvent/space filler, as a reagent, and as an acid/base. Liquid ammonia can easily act as a solvent (and it does get used in research as one), and as a reagent for similar but different reactions. It's a good base, but makes a poor acid (OH- is relatively stable but NH2- is angry). The density thing really doesn't matter for the majority of our planet even; if it never freezes you never have to worry about solid density.
 
Tuco

Tuco

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AngryGerbil_sl said:
Tocu, with your background in chemistry, is it correct to say that although other life forms may use silicone or something else as its Lincoln Logs instead of carbon, it will still always need liquid water? Water being the universal solute, necessary for osmosis, and the only substance that is less dense in its frozen state, etc etc?

If so, then looking for organic molecules is too narrow of a search. The life we are looking for may not even use carbon, and carbon itselfisorganic chemistry. We already know many forms of life that don't need oxygen so that's also too narrow. The first thing we need to find is liquid water. Yes? No?

How would ammonia replace water? I guess that's my question.
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I know very little about chemistry and less about organic chemistry. I know so little that a chemist would likely laugh at my musings in their field.

I do know that organic chemistry is generally defined as 'chemistry involving carbon atoms' because that makes a lot of sense.

But in a broader sense, organic matter could be defined as 'matter that came from living tissue'. If we found organic matter that did not use carbon in its chemistry, we'd have to change our definition of 'organic chemistry'.

And we'd have a massive explosion in known organic chemical compounds. Not that it'd be particular useful on earth.

Ex: methane's cousin would beSilane - Wikipedia, the free encyclopedia

Here's a quote from HG Wells that fantasizes the kind of thing I'm thinking,
"One is startled towards fantastic imaginings by such a suggestion: visions of silicon-aluminium organisms - why not silicon-aluminium men at once? - wandering through an atmosphere of gaseous sulphur, let us say, by the shores of a sea of liquid iron some thousand degrees or so above the temperature of a blast furnace."
 
Furry

Furry

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Tuco_sl said:
...
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Earth has way more silicon than carbon, yet carbon life developed. While silicon is likely a possible basis for life, carbon has a lot of qualities that make it far better and more likely to develop into life.
 
Alex

Alex

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Whenever I think about lifeforms based on other elements I can't help but think of the movie Evolution.

rrr_img_105503.png
 
Szlia

Szlia

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Checking the Colbert-Tyson banter embedded above I then checked a couple other Tyson clips and in one he mentions carbon based life and the frequency of elements in the galaxy. It goes Hydrogen, Helium (inert), Oxygen, Carbon, others... And the first two account for 98% of the mass! So he goes on to say that the quantity of carbon in the galaxy along with it's huge spectrum of possible compounds make it the natural candidate for complex living organisms. But it's true that it's a bit strange when you consider planetary composition as it is largely dominated by heavier elements (with the exception of oxygen). Mmmmh.... I guess it's true we are made of stars. Thanks for the carbon and hydrogen!
 
Chris

Chris

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Szlia_sl said:
Checking the Colbert-Tyson banter embedded above I then checked a couple other Tyson clips and in one he mentions carbon based life and the frequency of elements in the galaxy. It goes Hydrogen, Helium (inert), Oxygen, Carbon, others... And the first two account for 98% of the mass! So he goes on to say that the quantity of carbon in the galaxy along with it's huge spectrum of possible compounds make it the natural candidate for complex living organisms. But it's true that it's a bit strange when you consider planetary composition as it is largely dominated by heavier elements (with the exception of oxygen). Mmmmh.... I guess it's true we are made of stars. Thanks for the carbon and hydrogen!
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I seem to remember that most stars only make Helium, Oxygen and Carbon? Heavier stars can make more and supernova makes the rest.
 
AngryGerbil

AngryGerbil

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Chris_sl said:
I seem to remember that most stars only make Helium, Oxygen and Carbon? Heavier stars can make more and supernova makes the rest.
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Iron is 'nuclear ash'. A regular star can potentially create elements as heavy as iron (or anything below it, including carbon) via its normal fusion. Once it starts making iron in its core though, that is the end of the line. Anything heavier than iron requires a supernova.
 
AngryGerbil

AngryGerbil

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Tuco_sl said:
I know very little about chemistry and less about organic chemistry.
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You know what? I misread you from the get-go Tuco. I thought you were saying that 'Hey, I know a little bit about organic chemistry, and I think X, Y, and Z."

But really you were actually saying, "I honestly don't know much about organic chemistry."

I got that all totally wrong. My mistake. My apologies. I misread the whole thing.

Cheers.
 
khorum

khorum

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The DSCOVR Climate satellite orbits over a million miles from earth for its super high res imagery. It let it catch the photos of the dark side of the moon:

55c23e311d00002f00143ed5.gif


The nazi bases are in the lower left quadrant. Near the future site of the gamergate lunar colonies.
 
iannis

iannis

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Yeah, that's sweet.

Anyone know what the blip in the background is? The first dot from an alien S.O.S.?

Haha! Fuck you fuckers. Ur fukt.
 
G

Grimey

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Is it just me or does the dark side look smoother? Should it be smoother from facing solar wind or rougher from getting more impact events?
 
iannis

iannis

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There are more mares on the near side for whatever reason. Mares are those basalt lakes, the splotches.

So yeah, the far side is smoother. You can't build nazi bunkers without doing some landscaping first.
 
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