In 1999 astronomers detected the first exoplanet–a planet in another solar system. The number of planets detected orbiting around stars other than our Sun has grown to more than 3,500 today. There are billions of stars in our Milky Way Galaxy so searching for other worlds is just getting started.
NASA’s main tool for finding exoplanets has been the Kepler space telescope. The method of detecting those planets is watching for occlusions. If there is a planet orbiting a star, it will sometimes pass in front of that star from our viewpoint causing an occlusion or mini-eclipse. The planets are too small for us to see, but we can see a small dip in the light coming from the star. If the dip comes on a regular interval that means it might be an orbiting planet. The amount of the dip in light level indicates the size of the planet in relation to its star. Using this method of detection, astronomers have compiled a catalog of detected planets.
As I said, until now the Kepler telescope has been the method for finding most of these planets, but it will soon end its life. However, 2018 will be the beginning of new opportunities to look for exoplanets because of two new satellite-based observatories. Very soon NASA will launch TESS. That stands for Transiting Exoplanet Survey Satellite. By the end of the year, the European Space Agency (ESA) will launch CHEOPS or Characterising Exoplanet Satellite. (Aren’t you glad we have acronyms.)
The Kepler telescope was very good at searching for other worlds, but only in a small area of the sky. TESS will take a much wider view with the hope of finding many more. For obvious reasons, so far most of the planets detected are giant planets. TESS will be targeting bright stars in the hope of finding smaller planets that more closely resemble Earth. Astronomers will be able to target TESS more precisely toward selected stars.
It will be interesting to see what new discoveries will come from the investment of time and more than a quarter of a billion dollars. So far there have been no more than a dozen planets that even come close to being possible outposts for life. As we have said before there are many parameters required to sustain any kind of life and even more to support advanced life. We have also said many times before that whether there is life anywhere else in the cosmos has nothing to say about whether God exists. A God who is great enough to create the cosmos can create life anywhere He chooses. We are just glad He chose planet Earth so scientists can continue searching for other worlds.
–Roland Earnst © 2018