Exoplanets are the planets closest to our solar system. As space exploration, travel, and the related technologies continue to advance, the idea of finding exoplanets to explore, mine, and/or live on is a closer reality. NASA says they have discovered 3,431 confirmed exoplanets. Physicist Stephen Hawking stated his support for finding exoplanets and setting up space colonies in a dramatic manner at the University of Cambridge this year.
“[W]e must … continue to go into space for the future of humanity. I don’t think we will survive another 1,000 years without escaping beyond our fragile planet.”
While this may be a somewhat disturbing prediction for those of us who have kind of gotten used to living on Earth, it is exciting too. While caring for the Earth’s environment is likely our most vital priority, the discovery of other inhabitable planets is also important and, like many scientific explorations, may lead to unintended discoveries and benefits for our planet. NASA looks for exoplanets in five ways: searching for shadows, watching for wobble, taking pictures, minuscule movements, and light in a gravity lens” (more details here).
The Planet Orbiting Our Nearest Star Might be Habitable
NASA announced in October of 2016 that a “rocky extrasolar planet with a mass similar to Earth’s was recently detected around Proxima Centauri, the nearest star to our sun.” An international group headed up by Marseille Astrophysics Laboratory researchers are studying the planet’s dimensions and surface properties in order to determine if it may hold liquid water on its surface and so be habitable for humans.
Proxima Centauri is a red dwarf that is significantly smaller and less bright than our sun. It may have more than one planet and the one that has now been observed has been called Proxima B. Proxima B is 4 light-years away, 1.3 times Earth’s mass, and orbits at one-tenth of the distance between our sun and Mercury. Because the star is smaller and dimmer than our sun, this is thought to still be within a habitable zone.
Scientists have not been able to determine the planet’s radius at this point, which puts a damper on their ability to learn about its appearance and composition. The team from Marseille Astrophysics Laboratory is currently trying to determine the radius by working from the mass, which they are in turn exploring through analyzing different possible compositions with “a model of internal structure.” They are simulating
“potentially habitable planets, simulating dense and solid planets, formed with the metallic core and rocky mantle found in terrestrial planets in our solar system. They also allowed the incorporation of a large mass of water in their composition.”
Some of the different composition scenarios they are working with include a dry planet, an ocean planet, or a planet similar to Mercury, with a big metal core that accounts for two-thirds of the planet’s mass. Scientists will continue to observe Proxima Centauri and B and measure the stellar presence of heavy elements to try to determine Proxima B’s composition more accurately.
In other space exploration news,
The Largest Space Telescope Ever is Ready for Launch Condition Testing
NASA, the European Space Agency, and the Canadian Space Agency have been working for 20 years to complete the optical and science segments of the James Webb Space Telescope (JWST). Now that the center of curvature test of the telescope has been completed, it stands upright in the enormous NASA Goddard Space Flight Center clean room and is ready for launch condition testing. The JWST is scheduled to launch in the fall of 2018 and will use red and infrared light to provide images of galaxies formed billions of years ago and of nearby planets and solar systems with never-before-seen sensitivity. It will be an invaluable guide in looking for habitable exoplanets.
The JWST has three main components: the telescope, a spacecraft bus with propulsion and communication systems, and a sunshield, which keeps the sun’s heat from interfering with the sensors. The primary mirror of the telescope consists of 18 hexagonal gold-coated beryllium ore mirrors. After four years of preparation, the center of curvature test was carried out, which is an optical measurement of the mirror’s shape and position. Laura Betz of NASA explains that, “making measurements of the mirror shape and position by lasers prevents physical contact and damage (scratches to the mirror).” These measurements are compared to an ideal computer generated hologram of the mirror. The measurements will be repeated after vigorous launch environment testing, in which the telescope will undergo extreme sound, vibration, and temperature conditions, to determine if the launch will degrade JWST performance. The JWST is designed to have a mission of at least five years and hopefully a lifetime of 10. You can check out NASA Goddard’s YouTube video on this milestone here, in which the JWST is described as “our new eye on the universe.”
The passing of John Glenn, the first American to orbit the Earth, in December of 2016 is a potent reminder of how far space exploration has come and reminds us to appreciate all of the pioneers who have already braved the vast unknown. Space travel and colonization are becoming more ubiquitous in the news, thanks in no small part to the enterprises of Elon Musk’s SpaceX, a non-governmental aerospace manufacturer and space transport company. Their ongoing work aims to cut down on the cost of space travel and eventually colonize Mars.
If space and space exploration seems very removed to you and you’d like that to change, you might enjoy exploring the site Spacehack.org, which is an online directory of ways that anyone can contribute to and participate in space research and exploration. One example they include is Galaxy Zoo Radio, in which you can help astronomers hunt through space images for signs of black holes. Happy hunting!