Yesterday, NASA reported a record-breaking discovery of seven new Earth-size planets around a single star, three in the habitable zone:
The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system [TRAPPIST-1]. All of these seven planets could have liquid water – key to life as we know it – under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.
“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”More.
The planets are about forty light years from Earth, in Aquarius.
Our physics colour commentator Rob Sheldon offers,
The sun that they orbit is a brown dwarf. It puts out 0.04% of the heat that our own Sun does. In order to be in the “habitable zone” where water is liquid, they orbit at 0.01 AU from their sun, where Earth is 1AU and Mercury about 0.3 AU from our sun. A “year” on these planets is 1 day, 2 days, 3 days, 6 days for the inner few. They are so close to the “brown dwarf” sun that they experience huge tidal forces that force one side of the planet to stay facing their sun. They are also so close that they are exposed to all the “flare particles” released from magnetic activity, so it would suggest one side of each “planet” is scorched and radioactive, while the other side is figid and frozen. Not exactly hospitable.
They looked for signatures of Hydrogen and Helium and saw none, which suggests that none of the planets is a “gas giant” like Jupiter, and also none of them has an extended oxygen or CO2 atmosphere like Earth or Venus. Many such “solar systems” with “earthlike” planets around “brown dwarf” planets have been seen already, with little hope of life on them. But what makes this one special is that there are 7 such planets all strung out in a line. The “perhaps there’s life” is a red herring to make this newsworthy.
See also: Religion and ET: What’s wrong with science writing today
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