Many Worlds

I had the pleasure of reporting and writing the Many Worlds column — sponsored by NASA’s NExSS initiative and the Lunar & Planetary Institute — for almost eight years. But the run came to an end in October. Now an archive of the more than 400 columns is easily available at http://www.manyworlds.space.

In a solar system far, far away, life of some sort is just waiting to be found. Or so the world of astrobiology sure hopes it is. The new player in the astrobiology world, now called the Habitable Worlds Observatory (HWO), is planned to launch in the 2040s if all goes well.

Beware easy answers to the question of whether life exists beyond Earth. Be they “alien” skeletons in Mexico City, interstellar probes that briefly pass through our solar system, UFOs of all sorts and claims to have found “biosignature” chemical byproducts of life around planets where many other factors say that life cannot exist — their chances of being meaningful are vanishingly small.

Bits of pebbles and dust from the asteriod Bennu that were collected during the long journey of the OSIRIS-REx spacecraft should be landing in the Utah desert later this month. The delivery will be a first for NASA — its first sample return from an asteroid and one of a very small handful of space objects ever brought to Earth by humans from anywhere but the moon.

An Indian spacecraft landed on the moon this month and a pioneering Japanese lunar  lander is awaiting an imminent launch. A Russian craft trying to land in the same area — the southern polar region — recently crashed, as did a private effort by a joint Japanese-United Arab Emirates group and one by several Israeli companies. A Chinese rover has been exploring the far side of the moon for numerous years now, and China completed a lunar robotic sample return mission.

In our Earthling minds, planets exist in solar systems with a Sun in the middle and objects large and small orbiting around it. This is hardly surprising since planets are pretty much exclusively illustrated in solar systems and, until the onset of the 21st century, no other kind of planet had been identified.

Optical SETI searches for distant laser bursts as possible signs of technologial socieites in very far away solar systems. (SETI) The Search for Extraterrestrial Intelligence (SETI) began decades ago as an effort to pick up radio signals from distant civilizations. The effort was centered at the Green Bank Observatory in West Virginia and was by today’s standards quite rudimentary.

There are three planets or moons in our solar system known to now have, or once had, surface rivers, lakes, deltas and a hydrologic system. There’s Earth, of course, Mars long ago when it was warmer and wetter, and the so different yet so similar rivers of hydrocarbons on Saturn’s moon, Titan. Understanding the dynamics of rivers in particular is crucial to understanding the workings of a planet or moon.

Among the most eagerly awaited results from the early observations of the James Webb Space Telescope (JWST) is whether or not the seven rocky planets of the TRAPPIST-1 system have atmospheres. The TRAPPIST-1 planets are close to us (40 light-years away), are all solid rather than gaseous, and they orbit a cool and small sun that makes the planets easier to observe and measure.

Saturn’s moon Encedalus sends out regular plumes of water vapor — as seen here as imaged in false color by the Cassini spacecraft. New research into Cassini data has detected the element phosphorus, a potentially very significant discovery. (NASA/JPL-Caltech) The elements needed for life as we know it are carbon, hydrogen, oxygen, nitrogen sulfur and phosphorus.