Earth Had Oxygen Much Earlier Than Thought

[longship]

1. Interesting.

I heard an argument against the SETI searches by a physicist who apparently didn't like it.

His claim was that astronomers on a distant planet will likely have the ability to detect Earth's oxygen-rich atmosphere from great distances. (Astronomers here are close to being able to do just that. Google "James Webb Space Telescope".) An oxygen rich atmosphere is an almost certain indication of life. The thing is, only a few millions of years is required for a star to approach Sol in the galaxy. Any long lived civilization detecting Earth's oxygen atmosphere would want to investigate.

Of course, this is ridiculous as sending a spacecraft to Earth is a very expensive prospect whereas sending a radio signal is relatively cheap. But I found the argument interesting.

When the James Webb gets to its Lagrange point, we'll likely soon know about planets with life. At least one can hope.

We are not alone.