Kevin_Hall Posted December 24, 2021 Posted December 24, 2021 Astronomers have found 70 wandering planets after having processed 20-years collected data. Wadnering planets are the planets that are located in interstellar space and are not gravitationally associated with a star or brown dwarf. Over the past 20 years, about two dozen such bodies have been discovered. The source: https://www.nature.com/articles/s41550-021-01513-x
Andrewler Posted December 25, 2021 Posted December 25, 2021 Has life been discovered on those planets?
TheVat Posted December 25, 2021 Posted December 25, 2021 I'm going to take a wild guess and say that we might have heard something in the media or in scientific journals, if life had been discovered. BTW, Andrew, given the indirect methods of observation used, what sort of remote sensing methods do you think could detect signatures of life on such bodies?
Andrewler Posted December 25, 2021 Posted December 25, 2021 Marks of life can be detected by their wavelengths of light, as the telescope collects spectral data on the planet. I hope that the super telescope James Webb is about to launch into space will be a powerful enough tool to give the final answer. 1
TheVat Posted December 25, 2021 Posted December 25, 2021 Spectral data? So you are suggesting that, though these are dark sunless planets, they could have some thermal signature that we would pick up if they were close enough? Would a weak IR signature provide any spectral data that indicated life? That's the part I don't understand. It would indicate either residual heat still stored after ejection from a planetary system or possibly radioisotopes in the planet's interior generating heat. But life?
beecee Posted December 25, 2021 Posted December 25, 2021 (edited) 4 hours ago, Andrewler said: Has life been discovered on those planets? 4 hours ago, Andrewler said: Marks of life can be detected by their wavelengths of light, as the telescope collects spectral data on the planet. I hope that the super telescope James Webb is about to launch into space will be a powerful enough tool to give the final answer. We have also discovered 4000 odd "normal" planets with a parent star/s, and are still not sure whether they contain, or can contain life or not...that even applies to some extent within our solar system. eg: Europa, Enceledus. Edited December 25, 2021 by beecee
Ken Fabian Posted December 28, 2021 Posted December 28, 2021 On 12/26/2021 at 2:57 AM, Andrewler said: Marks of life can be detected by their wavelengths of light, as the telescope collects spectral data on the planet. I hope that the super telescope James Webb is about to launch into space will be a powerful enough tool to give the final answer. With conventional exoplanets, that transit their parent star, yes. Wandering "free" planets, no. On 12/26/2021 at 3:08 AM, TheVat said: Spectral data? So you are suggesting that, though these are dark sunless planets, they could have some thermal signature that we would pick up if they were close enough? Would a weak IR signature provide any spectral data that indicated life? I don't think that determining atmospheres of 'free' planets - of any planets using it's IR detectors - is what Webb is expected to do but it is expected to detect more such planets with other instruments. The Webb telescope is expected to be able to get spectral data from light passing through the planet's atmosphere during transits across their parent star - the more conventional "exoplanet". Free planets might be more problematic for atmosphere detection than planets that don't transit their Primary. I don't know if it will ever become possible to use more distant starlight passing through planetary atmosphere in a similar way - maybe not, given how weak the light source would be. A Nitrogen and Oxygen atmosphere would almost certainly be considered a product of life, as would other atmospheric indicators. Not sure what the specific characteristics of earlier (pre-oxygen) Earth atmosphere's would be, but there would be indicators of life amongst them.
mistermack Posted December 28, 2021 Posted December 28, 2021 What are the chances? Finding oxygen would be very odd, since there would be no green plants to produce it or sunlight to power them. The temperature on a wandering planet is likely to be extremely cold, having no light input from a star. I guess you could have interaction with a moon, giving heat to an ocean due to tidal forces. In that case, you could get bacteria that get energy from chemicals released in "smokers" like in our deep oceans.
Kevin_Hall Posted December 28, 2021 Author Posted December 28, 2021 On 12/25/2021 at 5:18 PM, Andrewler said: Has life been discovered on those planets? Waiting for JWST to tell us 😀. Joke Actually not yet, but there is an interesting arcticle about it in Discover mag https://www.discovermagazine.com/the-sciences/can-life-exist-on-a-rogue-planet
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