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edited Oct 18, 2017 at 8:25

Yes, scientists have thought about those two questions.

The mass of the earth is not large enough to curve spacetime sufficiently that you would be able to see the back of your own head through a telescope. For you to be able to do this, you would need to be positioned just on the edge of the event horizon“photon sphere” of a black hole (as per Solenodon Paradoxus’ comment, positioning yourself on the event horizon would not allow you to see the back of your head).
Of course it is possible that you are right. The more pertinent point, however, is that we would have expected that life may have formed in other systems long before it emerged on our planet. Life has, on our planet, existed for (approximately) $\frac{1}{3}$ of the duration of the universe (since the big bang), while galaxies and solar systems of all types have existed for the vast majority of time. Even in our own galaxy, and that of our neighboring galaxies, there have been hundreds of billions of stars since the formation of the galaxy; yet, as far as we know, we are the only life forms to exist. So, in answer to your question: yes, life may exist outside of the range of our vision; however, we should expect it to exists within our range of vision, and look for it there—rather than trying to look where we cannot.

Yes, scientists have thought about those two questions.

The mass of the earth is not large enough to curve spacetime sufficiently that you would be able to see the back of your own head through a telescope. For you to be able to do this, you would need to be positioned just on the edge of the event horizon of a black hole.
Of course it is possible that you are right. The more pertinent point, however, is that we would have expected that life may have formed in other systems long before it emerged on our planet. Life has, on our planet, existed for (approximately) $\frac{1}{3}$ of the duration of the universe (since the big bang), while galaxies and solar systems of all types have existed for the vast majority of time. Even in our own galaxy, and that of our neighboring galaxies, there have been hundreds of billions of stars since the formation of the galaxy; yet, as far as we know, we are the only life forms to exist. So, in answer to your question: yes, life may exist outside of the range of our vision; however, we should expect it to exists within our range of vision, and look for it there—rather than trying to look where we cannot.

Yes, scientists have thought about those two questions.

The mass of the earth is not large enough to curve spacetime sufficiently that you would be able to see the back of your own head through a telescope. For you to be able to do this, you would need to be positioned just on the edge of the “photon sphere” of a black hole (as per Solenodon Paradoxus’ comment, positioning yourself on the event horizon would not allow you to see the back of your head).
Of course it is possible that you are right. The more pertinent point, however, is that we would have expected that life may have formed in other systems long before it emerged on our planet. Life has, on our planet, existed for (approximately) $\frac{1}{3}$ of the duration of the universe (since the big bang), while galaxies and solar systems of all types have existed for the vast majority of time. Even in our own galaxy, and that of our neighboring galaxies, there have been hundreds of billions of stars since the formation of the galaxy; yet, as far as we know, we are the only life forms to exist. So, in answer to your question: yes, life may exist outside of the range of our vision; however, we should expect it to exists within our range of vision, and look for it there—rather than trying to look where we cannot.

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created Oct 18, 2017 at 7:44

Yes, scientists have thought about those two questions.

The mass of the earth is not large enough to curve spacetime sufficiently that you would be able to see the back of your own head through a telescope. For you to be able to do this, you would need to be positioned just on the edge of the event horizon of a black hole.
Of course it is possible that you are right. The more pertinent point, however, is that we would have expected that life may have formed in other systems long before it emerged on our planet. Life has, on our planet, existed for (approximately) $\frac{1}{3}$ of the duration of the universe (since the big bang), while galaxies and solar systems of all types have existed for the vast majority of time. Even in our own galaxy, and that of our neighboring galaxies, there have been hundreds of billions of stars since the formation of the galaxy; yet, as far as we know, we are the only life forms to exist. So, in answer to your question: yes, life may exist outside of the range of our vision; however, we should expect it to exists within our range of vision, and look for it there—rather than trying to look where we cannot.