Astronomers use several methods to detect exoplanets. As an exoplanet passes in front of its sun, it blocks a small amount of light. If a small drop in the luminosity of a distant star is detected, it may indicate that a planet is passing in front. Another method uses the fact that as a planet orbits around its star, the star also moves through a small orbit due to the planet’s gravitational pull. The motion of a star through an orbit causes changes in the frequency of emitted radiation, which can also be detected from Earth.
It seems to me that much of the evidence in astronomy is indirect – you cannot see a planet, but you can see a change in radiation from a star, and infer the existence of the planet. Even if you can take a photograph of a planet, and image from so far away doesn’t show much detail. Similarly, we can only collect indirect evidence for life on other planets. We do not have, and may never have, the technology to visit other worlds and observe their life for ourselves.
As an engineer, I don’t think I would like being an astronomer. I like being able to take things apart to see how they work. I think I would find myself incredibly frustrated if the objects of my study were too far away to observe directly.
I am, however, extremely impressed with the work astronomers do, and with the solutions they have developed to observe indirectly what we cannot currently observe directly. I found it especially interesting to consider the ways in which the study of life on Earth informs the study of life on other planets. It’s interesting to me to consider the ways in which life on Earth might or might not resemble life on other planets.
For most of the history of the Earth, all life was microbial. This leads astrobiologists to conclude that life on exoplanets would most likely be microbial as well – hence, not intelligent life that we could contact or speak to. I didn’t find it very disappointing to hear that most life out there is probably microbial – if anything, it’s cooler to me to think that intelligent life is currently evolving somewhere in the universe, as opposed to believing it already exists.
I appreciated learning about astrobiology, and, while I do not think it’s for me, I very much appreciate the ways in which astronomers and astrobiologists use incomplete data and indirect observations to learn about things we cannot see firsthand.
As a biology major, astrobiology seems incredibly exciting. Not only from the perspective of meeting an alien (since most likely aliens are just space bacteria) but also from comparing how those lifeforms might evolve on a planet with slightly different physical conditions. I also agree that the almost intangible nature of astronomy makes it a bit difficult for me to want to pursue a career in the field.
I find your post interesting in that how you think that alien microbes are far more interesting than a full-fledged life form. I agree that watching a planet evolve would be much more remarkable than to encounter a traditional alien. Trying to see how different forms of life use their resources to fulfill life functions (as we define it) would be something to note. I think we can find several earthly life forms that have overcome our definition of life.