When I first started studying Astronomy, my book brought me up the state of knowledge about 1940. However, I also was very aware of the space program that was rewriting those books. Mars was discovered to have craters. Venus was an oven the melted lead. And, astronauts walked on the Moon.
We always had suspicion of planets orbiting other stars, but we were left to science fiction to image those. Now through advanced optics and big new observatories, extrasolar planets have become a reality of science. Some have been imaged, but now we have a video of planets circling another star:
By studying meteorites, we can estimate the constituent parts of Terrestrial planets. In Paul Voosen’s article from Science Weekly, we find that water and other volatiles are present. Since meteorites are the building blocks of planets, it suggests that Earth like planets can form around other stars.
Here is another example of a close orbiting ‘Earth like’ exoplanet in a video from Dr. Becky Smethurst.
Dust grains are the formation of planets. Here is an effort to understand those grains:
Database of Extrasolar Planets:
Methods for finding exoplanets:
This helps determine the fraction of stars having planets and the number of planets per star for the Drake Equation.
Using spectra to determine composition and chemistry of atmosphere:
This relates to fraction of worlds having life from the Drake Equation.