In February, exoplanet hunters announced the discovery of seven rocky planets orbiting a star called TRAPPIST-1 only forty light-years away. Compared to our sun, TRAPPIST-1 is tiny, and all its planets orbit closer than Mercury orbits Sol. But three of them are still in the Goldilocks zone that could be “just right” for life, and all seven planets could theoretically hold liquid water. While Ethan Siegel introduces the neighboring star system with spectacular illustrations from NASA and ESO, Greg Laden notes that the practice of saying these images are artistic interpretations “has largely fallen by the wayside.” Instead, scientific outreach relies more heavily on imagination and storytelling in order to capture public interest.
The European Southern Observatory made major headlines with their discovery of an Earth-like exoplanet orbiting our nearest neighboring star. On Dynamics of Cats, Steinn Sigurðsson writes: “ESO researchers, using the radial velocity variability technique, have detected a quite robust signature of a planet with a mass of 1.3 Earth masses, or more, in a 11 day orbit around Proxima Centauri.” The planet is within the red dwarf’s habitability zone, but we don’t yet know if it harbors an atmosphere or liquid water. Greg Laden writes “now that we have an Earth-like planet in our sights, perhaps there will be impetus for both funding and effort to squint really really hard at it and see if any life is there.” Ethan Siegel says “we can use giant ground-based telescopes for high-resolution spectroscopic images of these worlds. We can use space-based telescopes with coronagraphs or starshades to image these worlds directly over time. Or we could undertake a journey across space.” Reflecting on the number and quality of exoplanets discovered in the last few years, Steinn Sigurðsson concludes “What a nice Universe.” Amen.
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On Significant Figures, Peter Gleick explains that growing populations worldwide have exerted peak pressures on water supplies, leaving entire regions more vulnerable to natural variations in rainfall. In turn, global warming has made these natural variations more extreme. One such variation is El Niño, when “droughts are typically more widespread and severe.” Dr. Gleick reports on the challenges faced around the world in 2016, as several historic droughts grow worse. Meanwhile, in honor of Earth Day, Ethan Siegel suggests we count our blessings: “there’s still no planet as friendly to life or hospitable to humans as Earth. It’s the fact that we went beyond the Earth and discovered the Universe that’s allowed us to appreciate just how rare, precious and special our home world is.”
I have been remiss in not posting articles from the homepage here on Page 3.14…so to catch up, here’s four at once.
No Beauty Without Water
On World Water Day, think of the water cycle that defines this planet. On The Pump Handle, Liz Borkowski writes “rivers often flow through multiple countries, and actions by one country or community can affect their neighbors’ ability to meet their water needs. Consuming too much water, or polluting a shared body of water, can make it hard for others to have enough for drinking, hygiene, agriculture, ecosystem health, and other needs.” Rivers and streams, in addition to being valuable resources, are fragile habitats, and vital to all the lands they flow through. Most rivers depend on rainfall for replenishment—and many parts of the world face worsening drought on top of pollution and exploitation of waterways. Global warming is only making things worse. Peter Gleick offers some facts on Significant Figures: “Around 80 percent of all of the freshwater humans use goes to grow food. The rest is split among home, industrial, and commercial uses.” And “The majority of [all] species threatened with extinction are aquatic – threatened by human use and contamination of water.” As many rivers will show you, water is a beautiful thing. It goes around the world, again and again, and if it must pass through our faucets first, let us take good care of it.
Lots of Latitude for Life
Extraterrestrial life looks ever more likely with new findings about planets and solar systems. The brightest stars in the sky are often very large and distant, while nearer stars may be smaller, dimmer, or invisible to the naked eye. On Starts With a Bang, Ethan Siegel writes that the nearest star to us, Proxima Centauri, “a red dwarf star that’s just 12% the mass of the Sun, and only 0.0056% as luminous” was not observed until 1915. And the third-closest star system was discovered in 2013 and announced this week. Ethan continues: “more than 400 years after the invention of the telescope, we still don’t know how many (and what types) of stars there are just in our own backyard in space.” On Dynamics of Cats, Steinn Sigurðsson summarizes other astronomical research, saying “the occurrence rate of Earth size planets in the habitable zones of low mass stars is about 50%” and “if we look at the 10 or so known low mass stars within about 10 light years of the Sun, we expect essentially all of them to have low mass planets, and there should be about 5 roughly Earth size planets within the habitable zone of their parent star.” Even here in our own solar system, the ubiquity of life remains plausible, as NASA announced that the Curiosity rover discovered evidence that Mars was once habitable and chemically conducive to life. On Universe, Claire L. Evans imagines drinking from an ancient Martian river: “Your thirst slaked, you brush the red dust from your knees and stand to see the Earth, a significant blue dot on the horizon.”
Greg Laden reports that researchers have discovered some insect wings “can physically kill bacteria by poking and shredding them with tiny pointy structures.” The studied clanger cicada (Psaltoda claripennis) exhibits wing surfaces with nanoscopic arrays of needle-like nanopillars sticking out. Errant bacteria come to rest on these wings as if a bed of nails—except, as Greg says, “where the force involved with the bed of nails is gravity, gravity has nothing to do with the bacterium interacting with the nano spikes.” On Life Lines, Dr. Dolittle writes “some scientists see this as an opportunity to create anti-bacterial surfaces in public places simply by coating the surface of objects with nanopillars.” And Greg says “obviously, we want to make all doorknobs and toilet seats out of this stuff.” Good idea, but as with antibiotics, some bacteria are tough enough to survive.
Confronting Keystone XL
ScienceBlogs would like to officially welcome Dr. Peter Gleick, co-founder and president of the Pacific Institute, to the network. On his new blog Significant Figures, Dr. Gleick weighs the pros and cons of Keystone XL, the “proposed large pipeline project to expand the capacity to bring fossil fuels derived from the Athabasca oil sands region in Alberta, Canada south through the United States.” He says it is time to say “no” to such infrastructure, asking “How can we cheer at the profits being made by energy companies in our investment portfolios or institutional endowments when those profits come at the expense of our own and our children’s planetary health?” He also says “the climate will continue to change in an exponentially increasing and worsening way unless we reduce emissions.” We will run out of fossil fuel eventually, but Greg Laden says there is still two or three times as much fossil fuel left underground as we have already extracted and burned. Do we have the willpower to leave it there? Or will we suffer a hotter, uglier, less diverse world with deadlier weather and rising seas?