|By "close", you mean "~23 million miles away" (rounded down). And that's when they are closest to each other in orbit -- usually it is much farther away than that.|
To put that in perspective, The deepest known point of the Marianas trench (deepest point known on Earth) is ~7 miles (rounded up)
So... unexplored areas on Venus = 23000000 miles away
Unexplored areas on Earth = 7 miles away
Yeah... Venus is closer than other planets. But it's still EXTREMELY far away.
Yeah but there are different reasons why it is difficult to probe the deep ocean and distance isn't one of them.
23000000 is actually not very far at all in terms of raw space because you can travel at extremely high speeds in space, and high travel speed isn't difficult or expensive for us to achieve. It's getting out of Earths atmosphere which is expensive, and designing and building the probes.
We have a probe out their right now which is about 10 billion miles away from earth which we are still in communication with.
And I don't think that probing for life is necessarily that difficult either. One of our first times on Mars, Viking missions ( late 70's) , we looked for microbial life, and we found something which they couldn't tell whether it was life or not.
|The primary scientific objectives of the lander mission were to search for biosignatures and observe meteorologic, seismic and magnetic properties of Mars. The results of the biological experiments on board the Viking landers remain inconclusive, with a re-analysis of the Viking data published in 2012 suggesting signs of microbial life on Mars.|
As far as I understand, since then we have not looked for life on Mars, even the recent exploration in 2012, they conducted no tests for biological life. I'm actually not sure if we have conducted tests for biological life off this planet since then at all. And the tests they did even during Viking was only a scratch on the surface.
I personally think that it is likely that there is microbial life on Mars; maybe even on most relatively stable planets in some niche in some form. Mars certainly is promising at least.
The question is whether or not they will make the information public when they do find life on other planets, if they have not already. I know that question was a serious concern when we began space exploration. I think they probably erred on the side of leaving it an optional to not disclose. But that's kind of hard to achieve. Who knows what the internal policies are now days about these things.
The fact that we have only conducted one set of inconclusive test almost 40 years ago, makes me think that in the recent past they have either been doing this in secret, or have decided to not look in order to prevent finding it and causing a shift in human perspective with unpredictable consequences. But it looks like there are missions to look for life on Mars again planned for 2018.