Questions tagged [astrobiology]

Questions about the origins of life on Earth, and the existence and detection of extraterrestrial life.

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Calculating "maximum" distance to an alien civilization

I'm planning on making a video related to Fermi Paradox, and I've used Omni Calculator's Alien Civilization calculator as a reference. I noticed they have a field that calculates the "maximum&...
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1 vote
1 answer
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Could life develop in a galaxy with a quasar at its centre?

Quasars are a type of Active Galactic Nucleus that inhabit the centres of some galaxies. They are among the most energetic objects known in the universe, emitting up to a thousand times the energy ...
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2 votes
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Infrared ozone line detection

I was recently reading Jack R. Woods' response on this forum: Could the James Webb Space Telescope detect biosignals on exoplanets? In an ideal situation (say looking at absorption lines of a super-...
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What are opinions of most planetary scientists on this study (link below), were there already some complex reviews in scientific journals?

I remember this two year old article from Universe Today about this study, "Stepwise Earth oxygenation is an inherent property of global biogeochemical cycling", by Lewis J. Alcott, Benjamin ...
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4 votes
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What limits can we set about life beneath the ice of Europa?

Do we know enough about the conditions beneath the ice of Europa to say anything about the complexity of life that may live there? Can we rule out macroscopic life?
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What is the probability of life having developed or going to develop in our solar system another time?

I'm sorry I am not quite sure this question satisfies this point: Questions that are purely hypothetical, for example a question such as 'Could a black hole destroy the universe' or 'What if our ...
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Could Enceladus be too salty to support life?

The process of osmosis makes it possible for water to be sucked through a semi-permeable membrane in order to balance the concentrations of two solutions. Thus, a sufficiently salty ocean might drain ...
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1 vote
1 answer
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Did we adapt to Earth or Earth to us? [closed]

I often hear that Earth is a unique planet because it has life. We also see a proper balance between plants and humans and other animals. Why is life not possible on another planet? Often people say ...
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19 votes
1 answer
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Serious alternate form of the Drake Equation, or graffiti?

Where I live it is very common to see jackets and T-shirts with familiar yet casually garbled or modified content (example) I recently spotted what looked a lot like the Drake equation on the back of ...
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4 votes
1 answer
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Eccentricity of Exoplanets

The field of astrobiology specifically discovering other planets that revolve around the sun-like star (also known as Exoplanets) has risen since 1990, but certain orbits of exoplanets are observed to ...
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1 vote
1 answer
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what would the mass and density of Sirius A be if the mass of Sirius B is roughly the same as the Earth?

I am writing a blog post and while I am interested in astronomy I havent done any physics like this since high school. My question is: what would the mass and density of Sirius A be if the mass of ...
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Updrafts on Gas Giants

Gas giants put out a fair amount of heat from gravitational collapse, so there's bound to be quite a bit of upward moving winds. If Carl Sagan's idea about aerial ecologies pans out, could larger ...
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4 votes
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Why the habitable zone of a binary star is a disc and not a sphere?

I understand that the orbit of a planet will always be flat, so there is no point on making a sphere out of the HZ when we consider one star, but what about binary stars? For example, this binary ...
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1 vote
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Is there a useful measure of how "life-dominated" a planet is?

If life exists on Mars or Venus, then in contrast to life on Earth, it must be "just scraping by". I can imagine a few ways to quantify this: Life on Mars or Venus is hard to detect -- any ...
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8 votes
1 answer
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What are the prospects for follow-up observations of phosphine on Venus?

Today, it was officially announced that astronomers have detected phosphine on Venus via the $\text{PH}_3(0\to1)$ transition (Greaves et al 2020). While the line was found by both the James Clerk ...
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Can concentration of gas in exoplanet atmosphere be found out from wavelength and absorbing radius from spectral data?

I was working on exoplanet spectral data from which I need to infer the concentration of gases. However, the exoplanet spectroscopy data contains only absorption wavelength and absorption radius. Is ...
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4 votes
1 answer
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Why N$_2$ is a non-absorbing species in the spectrum of the Earth?

The transmission spectrum of the Earth atmosphere is like that (Kaltenegger & Traub 2009): As you can see, you can find many absorption lines related to some components of Earth's atmosphere: H$...
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11 votes
5 answers
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Why there are no terrestrial planets with a subsurface ocean?

Subsurface oceans in satellites are pretty common: Europa, Enceladus, Ganymede, Callisto, maybe Pluto... This is due to tidal heating of their host planet, Jupiter and Saturn, which heats up the inner ...
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How is an exoplanet characterised as "Earth-Like"?

Which features or characteristics are taken into account to characterize an exoplanet as "Earth-Like"?
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Will the conditions that allow life to evolve still be around in a trillion years?

Some billions of years ago, systems like the Earth couldn't emerge and therefore life couldn't arise, because not enough of the heavy elements had formed yet. Assuming there'll neither be a big ...
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Do we know the fluctuations and constant temperature depth of the moon?

Disclaimer: I have no formal scientific training. From what I understand, surface temperature effects on Earth extend only so far into the ground so that at a certain depth the temperature remains ...
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How harmful is Saturn's magnetic field for human life?

AFAIK, Jupiter has the strongest magnetic field in the solar system, and it's so powerful that I've been told humans only could survive the radiation generated by it in its mooon Callisto, with proper ...
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Low mass cut-off for the Dharma Planet Survey's detection of habitable planets around 40 Eridani A?

News of the discovery of a potentially habitable planet around the star 40 Eridani A (about 16 light-years away) is interesting for reasons including a 1991 letter described below in Sky & ...
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3 votes
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Did this paper just argue that there is surely life on Titan?

I just read the popular press version of a new paper, and now I have a question about Titan. Here are some quotes from the pop article: A rocky, ocean-bearing planet with more than 0.1 percent ...
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5 votes
1 answer
877 views

Why are ice giants not considered suitable for life?

Ice giants are currently not considered suitable for life due to temperature, pressure and composition. This paper gives some parameters for life in regards to temperature, pressure and composition: ...
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0 votes
1 answer
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What possible effects of life replicating on gas giant atmosphere?

If bacteria managed to arrive then thrive somehow (if not already) on a gas giant could it cause the atmosphere to expand or contract in volume? Would living matter potentially induce energy into the ...
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12 votes
4 answers
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Why do aliens have to be carbon based lifeforms?

So correct me if I'm wrong, but when searching for extra terrestrial life, scientists usually search for signs they would expect for life on earth to thrive in. We look for conditions on planets that ...
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1 vote
2 answers
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Will biological process be disrupted under strong gravitational time dilation?

This question is raised by someone I've discussed with, after watching the movie "Interstellar", in which a clip showing Cooper and Amelia landing on Miller's planet near a super-massive blackhole and ...
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How could we search for life in TRAPPIST-1 [duplicate]

It is possible to search for life from here, how? What methods could be used? It is possible to look for organic matter? Could we know if there is life according to the components of the planets ...
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4 votes
2 answers
271 views

Why search for water?

Most of the news about extraterrestrial search focuses on possibility for existence of water and temperatures like earth. Why do scientists feel this would lead them to extraterrestrial life? After ...
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2 votes
1 answer
112 views

UK groups that investigate extraterrestrial life

What are some UK based groups that research astrobiology, especially the chance of extraterrestrial intelligence?
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3 votes
2 answers
263 views

Explaining the Drake Equation on a smaller scale

So me and my friend were planning a video to explain the Drake Equation (within a time limit of 5 minutes), and we needed some help. This video is aimed at explaining the concept to an age group ...
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Which elements are an indication of habitable exoplanets?

Using spectroscopy the chemical composition of exoplanets atmosphere is determined. As a scientist, what spectral lines would you look for? Which elements are relevant in pursue of a second earth?
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7 votes
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How much competition there is for jobs in astronomy compared to other fields of science?

I will soon finish a master's degree in computer science. I have been interested in astronomy for some time, which has included playing around with a Newtonian reflector telescope and reading about ...
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18 votes
3 answers
510 views

What earth organisms might survive if they arrived on Mars?

Contaminating other planets is a concern in space exploration. My question is what organisms, or small collections of organisms, from earth would be able form a self-sustaining population on Mars? I'm ...
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6 votes
2 answers
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Is axial tilt critical for life?

According to this explanation at the Georgia State University website, Axis Tilt is Critical for Life . . . The Earth's spin axis is tilted 23.5° with respect to the ecliptic, giving ...
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2 votes
1 answer
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Is liquid water on Mars such a big leap compared with ice?

I thought we have found bacteria or other kinds of life on Mars. Now it is liquid water. Is there such a big difference between liquid water and iced water?
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4 votes
1 answer
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Biosignatures for anaerobic or other early microbiology?

What are some possible atmospheric bio-signatures for a planet with anaerobic life? or even microorganisms before oxygen builds up in the atmosphere? Would there be a way of telling if methane, etc. ...
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11 votes
1 answer
302 views

Could the James Webb Space Telescope detect biosignals on exoplanets?

The James Webb Space Telescope (JWST) which is slated to launch in 2018 will bring us a better view of exoplanets, but will it be sufficient to detect signs of life on at least some of those worlds? ...
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0 votes
3 answers
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What is the next planned mission that can discover life on another planet? [closed]

I've heard that we have a great shot at finding life on Mars if we just drill deep enough down to the surface to the water and detect if its sterile or not. Are there planned missions to do this? If ...
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7 votes
2 answers
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Is early life required for life?

I was watching the new Cosmos and Neil DeGrasse Tyson said something that made me go hmmm... He mentioned that the only reason that the Earth did not experience the runaway greenhouse effect like ...
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