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Old 13th September 2019, 05:12 PM   #41
Myriad
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Today's xkcd (on topic)
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Old 13th September 2019, 05:37 PM   #42
Roboramma
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Originally Posted by Meadmaker View Post
The fact that they can do this is simply amazing.
Something that I find even more amazing: direct imaging.

http://www.planetary.org/explore/spa...t-imaging.html

And with new telescopes (like TESS) coming online soon, we will be getting better and better data on exoplanets.

Here's one amazing idea that might actually be possible soon:
https://www.nature.com/articles/s41598-017-07948-5

Quote:
Oxygen is one of the most discussed biosignature candidates5, 6. This is reasonable because two essential sources for oxygenic photosynthesis—light and liquid water—should by definition be available on habitable exoplanets, and oxygenic phototrophs can significantly change atmospheric compositions, as proven on Earth7. However, recent studies have shown that oxygen can also be a false positive sign of life on habitable exoplanets8,9,10,11. Thus, additional biosignatures will be necessary to determine whether oxygen is produced by phototrophs or abiotic processes. One possible additional biosignature for oxygenic phototrophs is the red-edge, which is a rise in a planet’s surface reflectivity between red absorbance and near-infrared (NIR) reflection due to vegetation12, 13. Although the red-edge position for Earth’s vegetation is fixed at around 700–760 nm, that for exoplanets may not necessarily be the same14,15,16. Thus, it is necessary to predict the red-edge wavelength position in advance in order to use it as an additional biosignature for distant habitable exoplanets.
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Old 13th September 2019, 06:45 PM   #43
PhantomWolf
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Originally Posted by Meadmaker View Post
The fact that they can do this is simply amazing.
What's even more amazing is that by looking at the star's natural spectrum we can determine what elements are in it, how far away from us it is, and if it is headed towards us or away from us. Then by looking at how the spectrum shifts back and forth over time, we can determine the mass and orbits of any planets large enough to cause a wobble that we can detect.

Add to that the size pf planets from the dimming (which gives the density when we have the mass) and the make up of those planet's atmospheres from more spectroscopy, and we can get a really good idea of what other solar systems (even in some cases as far away as another galaxy) looked like when the light left them.

All that just by looking at the light from the star!
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Last edited by PhantomWolf; 13th September 2019 at 06:48 PM.
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