Is there life on other planets?

Considering the number of stars in the universe, even if only a few of them have planets, it seems highly unlikely that Earth is the only planet supporting life.

However, it seems that all life on Earth evolved from a single ancestor, suggesting that abiogenesis is extremely rare. It is possibly so rare that it has only ever happened once anywhere?

This page is a permanent link to the reply below and its nested replies. See all post replies »

Tastyfrzz · 61-69, M

I would like to think so. It seemed to happen fairly quickly here. Possibly on multiple occasions. Since our planets' chemistry is pretty similar to most others it seems likely that it would be quite common.

suzie1960 · 61-69, F

@Tastyfrzz I'm not aware of any evidence that it occurred more than once here. I seems (and I'm open to correction) that all life on this planet evolved from a single source.

Tastyfrzz · 61-69, M

@suzie1960 There were some fossils discovered (so I read) that predate the formation of the moon. Very likely any life was destroyed by the impact. It is theorized that the proto-life could have frozen into cracks in rocks ejected by the impact then came back later and continued on development on the new planetary surface. There were several other periods of volcanism and impacts by asteroids that could also have destroyed all life. It doesn't take much. There even was some excitement a few years back when a meteorite that was determined to be from mars was discovered to have a possible fossilized bacteria within it. Since life on mars likely happened before life on earth it might be that we are the Martians.

Tastyfrzz · 61-69, M

@suzie1960 https://www2.jpl.nasa.gov/snc/nasa1.html

Tastyfrzz · 61-69, M

@suzie1960 http://adsabs.harvard.edu/full/1936PA.....44Q.442L

Tastyfrzz · 61-69, M

@suzie1960 https://www.newscientist.com/article/2131136-microbes-might-thrive-after-crash-landing-on-board-a-meteorite/

This one is even a bit more interesting in that is suggests that bacteria on earth have evolved to handle transport by meteorite. Apparently it happened often enough that the cells evolved so that the cell walls stiffen during impact so as to survive the temporary high pressures. It kind of proves that this did happen. Otherwise there would have been no need for such a feature.

suzie1960 · 61-69, F

@Tastyfrzz Thanks for those links. I'm a bit busy right now so I'll take a look later.