Yes, I’m still a scientist and today I wanted to share an image of the Milky Way to describe a recent scientific study I read. Back in 2009, the Kepler space telescope was launched with the mission to survey exoplanets orbiting nearby stars. What’s an exoplanet? I’ve written about them before, but an exoplanet is an object orbiting a star besides our own sun. By that definition, the Earth and planets in our solar system would be exoplanets if we viewed them from the perspective of a distant star.
To detect exoplanets, astronomers make careful measurements of the light intensity from a star. If an exoplanet passes between the Earth and the star, the light intensity of the star diminishes. Makes sense, sort of like a solar eclipse viewed from a great distance. By measuring the miniscule changes in light intensity over time, astronomers are able to determine the size and mass of the orbiting exoplanet. Exoplanets like Jupiter have been detected, as well as smaller ones like the Earth. It’s not easy, but astronomers are very clever, and they have some amazing instruments at their disposal.
Which brings me back to the Kepler space telescope. While orbiting the sun, this amazing 95-megapixel digital camera monitored the light from numerous stars over many months. That in itself is really cool but after analyzing the data from Kepler, astronomers were able to detect Earth-sized exoplanets in “hospitable” zone orbits around stars similar to our sun. Like our Earth, exoplanets in this zone could contain water in liquid form. That means oceans and rivers and streams and rain are possible on these far-off Earth-sized exoplanets. That’s a big deal, but even more amazing is that the results of the study reveal up to 300,000,000 Earth-sized exoplanets could exist in our Milky Way galaxy alone. Consider that billions of other galaxies exist beyond our Milky Way and the potential number of Earth-sized exoplanets is staggering. It’s exciting to consider the possibilities!
So, while you enjoy the attached panorama of our Milky Way, think of how many little dots in the image might have an Earth-sized exoplanet. Pretty cool!