NASA Hopes TESS Will Find as Many as 20,000 New Exoplanets

But are they being modest?


With SpaceX’s launch of the Transiting Exoplanet Survey Satellite (TESS) on Monday evening, NASA is shooting for the moon to get a better look at the stars and their satellites. TESS’s orbit will sling it around 240,000 miles from Earth, a vantage point that NASA scientists hope will allow it to capture evidence of up to 20,000 new exoplanets.

An exoplanet is any planet that exists outside of our solar system. As it stands, scientists have discovered and confirmed more than 3,700 exoplanets in the Milky Way, including gas giants like Jupiter, rocky planets like Earth, and even some dark planets that glide through the universe untethered by the gravity of a star. Most of these were discovered by NASA’s Kepler telescope, which launched in 2009 and has cataloged around 2,700 exoplanets.

NASA has lofty expectations for TESS.


Because we only have discovered around 3,700 exoplanets up until now, expecting TESS to find another 20,000 seems like a really ambitious goal. Then again, given how many potential exoplanets probably exist, 20,000 is actually a mere blip. Within the Milky Way galaxy alone, there are an estimated 400 billion stars, all of which are likely orbited by one or more exoplanets. This means that the number of exoplanets in our galaxy could be in the trillions. With the low-end assumption that the Milky Way contains 1 trillion exoplanets, discovering 20,000 would mean that TESS had found a mere .000002 percent of all the planets in the galaxy.

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Unfortunately, TESS isn’t powerful enough to examine the whole galaxy, which is kind of huge. Still, the satellite is set to monitor around 200,000 stars, so even if scientists only confirm a single exoplanet orbiting one-tenth of TESS’s marks NASA will have reached its goal.

You can watch the launch at 6 p.m. Eastern on Monday at NASA’s website.

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