Here’s a scientific obituary for a piece of equipment that discovered more than 2,000 planets in orbit around other stars.
NASA announced this week that its Kepler Space Telescope has “died,” meaning it ran out of fuel after more than nine years of operation.
Kepler, now orbiting the sun 94 million miles from Earth, peered into the Milky Way galaxy in search of slight dips in the brightness of stars. A very minor change could be caused by a planet in orbit around a star that blocked a little bit of the light, and the telescope was amazingly successful at finding those worlds.
Kepler (named after the 17th century German astronomer) is credited with finding a total of 2,681 planets outside our own solar system — two-thirds of the total number of orbiting planets that have been discovered.
Information from the 150,000 stars surveyed by the telescope led scientists to estimate that our Milky Way galaxy could contain as many as 11 billion rock-based planets orbiting the habitable zones of a sun-like star.
The telescope did its work despite a serious malfunction several years ago. Two of its four devices that pointed the spacecraft in the direction scientists wanted to survey stopped working.
NASA sought proposals for alternative missions, and settled on one that would allow the disabled Kepler to look for planets orbiting red-dwarf stars, which are dimmer than stars such as the sun. That produced information confirming at least 350 planets.
It’s fair to ask what’s the point of looking for Earth-like planets that are many light years away. After all, no matter how many planets Kepler and other telescopes discover, they’re all too distant for us to ever hope to travel to them.
A single light year equals nearly 6 trillion miles. That is an unfathomable distance for us but just a speck of distance in the universe.
The point of missions such as Kepler is to learn more about what’s out there, even if we’ll never see it up close. The telescope indicates that in the Milky Way, planets are more common than stars. Since the Milky Way has at least 200 billion stars, the possibilities literally are endless — and endlessly fascinating.
