Thursday, September 01, 2016

A Few Cosmic Distractions

If you need a break from the day-to-day struggles of life on the blue planet, here are a few recent astronomy developments that will send your thoughts drifting into space.

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First, let your mind wander to Hawaii. Not its lush, tropical beaches, but the deserted, rocky slopes of the Mauna Loa volcano. There, in an abandoned quarry, lies Mars. Not the real Mars, of course, but a 1200 square foot dome where crews of six live for months at a time, emerging only in space suits, as participants in the Hawaii Space Exploration Analog and Simulation (HI-SEAS). Earlier this week, the fourth mission of HI-SEAS wrapped up. This was the longest mission yet, at one full year.

HI-SEAS IV dome exit. On August 28, On August 28, 2016, the HI-SEAS IV crew exited the Mars habitat without spacesuits for the first time in 365 days.
Image Credit: University of Hawai'i News (CC BY-NC-ND 2.0)
During the past year, the crew members lived as if they were the only inhabitants on Mars, relying on shelf-stable food, solar power, limited internet access, and a ground-based crew with whom they could communicate, although only in ways that mimic what communication would be like from Mars. Funded by NASA, the focus of HI-SEAS is on crew composition and cohesion. The goal is to learn all we can about how to create and support teams that are highly effective on long exploration missions.

The “astronauts” perform activities similar to those required by astronauts on Mars—exercise, research, maintenance, and exploration. They also participate in behavioral and psychological tests. Several research groups collected data from this mission on topics ranging from team effectiveness to the impact of this kind of life on cognition. If this sounds like fun, you have until September 5, 2016 to apply for a place on the crew of the next two missions.

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Leaving the solar system behind, our next stop is about 4 light years away. In what may be the most exciting bit of recent cosmic news, astronomers confirmed that there’s a rocky, approximately Earth-sized planet orbiting Proxima Centauri. Aside from the sun, Proxima Centauri is the closest star to us. In other words, we’ve identified our nearest neighborhood.

This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB also appears in the image to the upper-right of Proxima itself.
Image Credit: Courtesy ESO/M. Kornmesser.
In an article published in Nature on August 25, researchers describe a planet with an orbit of 11.2 days—that's an 11-day year—and an estimated temperature that could support liquid water. Proxima b is much closer to its star than we are to the sun, but Proxima Centauri is much cooler so the planet is still in the Goldilocks zone. Past observations have hinted at its existence, but it was through a coordinated effort called the Pale Red Dot campaign this spring that scientists collected the evidence to definitively identify the planet. The evidence came in the form of radial velocity measurements, a regular and predictable change in the light reaching us from Proxima Centauri caused by the gravitational pull of an orbiting planet.

Could Proxima b support life? The debate rages on whether planets with its characteristics and proximity to a star could support liquid water and an atmosphere. According to the authors, we just don’t know yet. The size, structure, and temperature are promising, but Proxima b likely experiences strong magnetic fields and radiation from its star. It’s not clear what this means for the planet’s ability to retain an atmosphere. Even if conditions are right life may not exist there, but how can we not look?

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Drift out quite a bit further (about 300 million light-years), and you’ll find Dragonfly 44 among a cluster of galaxies known as the Coma Cluster. Last week an article published in The Astrophysical Journal Letters put this dim galaxy in the spotlight. Dragonfly 44 is similar in mass to the Milky Way, but recent observations indicate the vast majority of the mass comes from dark matter. In other words, stars make up only a tiny fraction of the stuff in Dragonfly 44.

 Taken by the Hubble, this image looks into a region of the Coma Cluster. The three bright objects surrounded by halos are galaxies in the cluster. The background contains more distant galaxies that aren’t part of the cluster.
Image Credit: ESA/Hubble & NASA; D. Carter (LJMU). Acknowledgement: Nick Rose. (CC BY 4.0)
Its very existence is puzzling. We know of other galaxies heavy on dark matter, but Dragonfly 44 is by far the most massive. Astronomers thought they had a pretty good handle on the formation of galaxies in its mass range, but the theory doesn’t explain a galaxy with so much dark matter. Now that we know such a galaxy exists, scientists are searching for others in hopes of finding one closer to us that is easier to study. In the meantime, the formation of Dragonfly 44 remains a mystery, like dark matter itself.

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I hope you enjoyed this brief distraction from your list of things to do today. It’s easy to get caught up in the nitty-gritty of daily demands. Sometimes it helps to take a minute and check in with the universe.

Kendra Redmond

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