The Cosmic Companion Newsletter August 3, 2019

Light sails, exoplanets, and more exoplanets!

Hello everyone!

The dream of sailing through space has filled the human psyche since the 17th Century. Now, LightSail 2 has brought this dream one step closer to reality by maneuvering in its orbit through the power of sunlight. The newest planet hunter in space, TESS, also returned some exciting new findings, including the discovery of a super-Earth not far from our own solar system. This begs the question, could this world, in our own stellar neighborhood, have life?

Let’s take off!

The Week in Space

TESS finds Three Strange Worlds Near Us - The Transiting Exoplanet Survey Satellite (TESS) spacecraft scored a hat trick of discoveries, finding three previously unknown planets surrounding the star UCAC4 191–004642. This system, now called TOI (TESS Object of Interest) 270, sits 73 light years from our own family of planets.

An infographic showing the relative distances of the three known worlds in the TOI 270 system. Image credit: NASA’s Goddard Space Flight Center/Scott Wiessinger

One of these worlds is a super-Earth, slightly larger than our own planet. The other two are sub-Neptunes. This class of planet is significantly larger than the Earth, but smaller than Neptune. Although worlds of this size do not exist in our solar system, they are common around other stars.

The two inner worlds are likely too hot to support life, but the third world in the system, TOI 270 d, could have temperatures capable of supporting living beings.

Read more:

TESS Finds First Nearby Super-Earth (and it Might be Habitable) - In another win for TESS, the orbiting planet-hunter also came across an additional world, near our own, that may be capable of supporting life.

An artist’s concept of GJ 357 d, orbiting its companion star. Image credit: NASA’s Goddard Space Flight Center/Chris Smith

The planet GJ 357 d orbits its parent star within the habitable zone, where temperatures are neither too hot, nor too cold, for liquid water to pool on its surface. This world has a mass six tomes great than the Earth, and it orbits its parent star once every 55.7 days. Sitting at the edge of the habitable zone around the star GJ 357, this would be an ice world, but a thick atmosphere could warm this planet enough to form oceans and seas. Astronomers are still uncertain whether this world holds on to enough atmosphere to make life there possible.

Accompanying GJ 357 d are two other planets, closer to the star, where surface temperatures are far too high for water, or life, to form.

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LightSail 2 Raises its Orbit, and the Future of Light Sails - LightSail 2, the tiny project from The Planetary Society, is now the most maneuverable light sail spacecraft ever designed. In place of chemical rockets, this spacecraft is propelled by a large sail that captures sunlight.

A computer simulation of the LightSail 2 spacecraft in orbit over Earth. Image credit: Screenshot from LightSail 2 animation from The Planetary Society.

LightSail 2 recently raised its orbit by 1.7 km (one mile), though the power of sunlight alone, becoming the first spacecraft in history to accomplish that task. This concept, first postulated by famed astronomer Johannes Kepler in 1607, is now a reality.

The Cosmic Companion talked with Bill Nye the Science Guy about what this technology could mean for the future of space exploration.

Read more:

Coming soon: The First Woman on the Moon: The Past and Future History of Women in Space by James Maynard

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- James