- Found: 1,100 Exoplanets
- Mars, Water, and the Case of the Missing Atmosphere
- Trees With Gold in their Leaves
- Habitable Zones and Kepler-69c: There's More to Learn
Crackpots, Dreamers, and NASA Design StudiesTerraforming, changing the environment of another planet to something we'd find comfortable, has been a "science fiction" idea for decades.
There was a time when I thought terraforming other planets was possible: and probably something we wouldn't have the technology to accomplish for centuries, or millennia. That may be true, but now I suspect that we're decades, a few centuries at most, from 'terraforming' parts of Mars.
What's changed my view is the continuing intense interest in settling Mars. Some of those folks are, most likely, crackpots. But some are practical scientists.
It looks like some of the students who participated in NASA's 1975 Space Settlements design study are now scientists: and never stopped thinking about ways to settle on other worlds.
Although I don't agree with the late Arthur C. Clarke on some things, what he said about the evolution of new ideas is, I think, generally true:
- "It can't be done."
- "It probably can be done, but it's not worth doing."
- "I knew it was a good idea all along!"
Folks who get conniptions about anything America does may be happy to know that students from India won a 2011 NASA space settlement design contest. Then again, maybe not.
The Ethics of TerraformingThe big question isn't so much whether or not we can change another planet into a reasonable facsimile of Earth, given time.
It's whether we should.
Provided that folks who run the terraforming projects don't hurt other people, I don't see a problem. Humans are designed to study, and manage, this universe. So far, we've learned quite a bit about how to work with Earth. We've also learned about things we never want to try again. Ever.
Trying isn't the problem.
Being greedy, stupid, and short-sighted is.
(from the United States Library of Congress, via Wikipedia, used w/o permission)
I've been over this before, including:
- "Fusion Power, Terraforming, and Old Dutch Windmills"
(October 11, 2013)
- "Love, Technology, and Being Human"
(October 6, 2013)
- "Asteroids, Comets, and Doing Our Job"
(September 29, 2013)
- "Designed as Stewards"
(March 17, 2013)
- "Earth Day, 2012: This Catholic's View"
(April 22, 2012)
1. Found: 1,100 Exoplanets
"Alien Planet Count Passes 1,000 Worlds, a Milestone"There isn't anything particularly significant about the thousandth planet in the Exoplanet Encyclopedia or Planetary Habitat Laboratory's The Habitable Exoplanets Catalog.
Mike Wall, Space.com 1 (October 23, 2013)
"Just two decades after first spotting planets orbiting a star other than our own sun, astronomers have notched a big milestone - the 1,000th alien planet.
"Two of the five main databases that catalog exoplanet discoveries list 1,010 confirmed alien worlds as of today (Oct. 23). That's a lot of progress since 1992, when researchers found the first-ever exoplanets orbiting a spinning neutron star, or pulsar....
"...The five main exoplanet-discovery databases, and their current tallies, are: the Extrasolar Planets Encyclopedia (1,010); the Exoplanets Catalog, run by the Planetary Habitability Laboratory (1,010); the NASA Exoplanet Archive (919); the Exoplanet Orbit Database (755); and the Open Exoplanet Catalog (948).
"The different numbers reported by the databases reflect the uncertainties inherent in exoplanet detection and confirmation."
The news excites me for about the same reason that outstanding scores excite a sports fan. It's also reflects how much we've learned recently about planets circling other stars: and how much we still have to learn.
One Galaxy, Billions of Worlds, in a Universe with Billions of Galaxies
"...the current tally is likely just the tip of the exoplanet iceberg. For example, a study published last year estimated that every star in the Milky Way hosts 1.6 planets on average - meaning that our galaxy likely harbors at least 160 billion alien worlds.If that study is accurate, and an average of 1.6 planets circle stars in this galaxy: our Solar system has a superabundance of planets: well over a half-dozen.
"And those are just the planets with obvious parent stars. Another recent study calculated that 'rogue planets' - those that cruise through space apparently unbound to any star - may outnumber 'normal' worlds by 50 percent or so...."
(Mike Wall, Space.com)
Maybe we live in a very unusual planetary system: or maybe we'll discover many more than 160,000,000,000 planets in this galaxy. Either way, we aren't likely to run out of places to go and things to learn for quite a while. Even after we thoroughly explore this galaxy, there are billions more. This is a big universe.
More about exoplanets:
- "Exoplanet tally soars above 1,000"
Melissa Hogenboom, BBC News (October 22, 2013)
2. Mars, Water, and the Case of the Missing Atmosphere
"Meteorite Study Suggests Mars Atmosphere Trapped in Rocks, Not Lost in Space"Tomkinson and the other scientists analyzed a small slice of the Lafayette meteorite. It's a nakhlite: a particular sort of rock that started as basaltic magma on Mars. That was a very long time ago: 1,300,000,000 or more years back.
Becky Oskin, Space.com 1 (October 22, 2013)
"The atmosphere of Mars may not have escaped into space billions of years ago, scientists say. Instead, the bulk of Mars' carbon dioxide gas could be locked inside Martian rocks.
"Most of Mars' carbon dioxide vanished about 4 bildflion [sic!] years ago, leaving a cold planet covered in a thin veneer of gas. But a new analysis of a Martian meteorite claims that some of the carbon dioxide disappeared into Mars itself, and not out into space as previous studies have suggested.
" 'This is the first direct evidence of how carbon dioxide is removed, trapped and stored on Mars,' said Tim Tomkinson, lead study author and a geochemist at the University of Glasgow in the United Kingdom. 'We can find out amazing things about Mars from the very small amount of sample that we have.'..."
More recently, an impact on Mars sent the Lafayette meteorite into space. About 3,000 years back it fell on Earth, where it was discovered: a little under a century ago.
More than you probably want to know about that sort of rock:
- "The nakhlite meteorites:
Augite-rich igneous rocks from Mars"
Allan H. Treiman, Lunar and Planetary Institute
(From http://www.lpi.usra.edu/science/treiman/nakhlite_rev.pdf (October 23, 2013))
Wet Rocks on MarsWhat's exciting about the Lafayette meteorite is what we've learned about its time on Mars. Its cracks and crevices contain clay and carbonates. This piece of rock was in water, where it absorbed carbon dioxide.
Rocks do that all the time here on Earth. Now we've got evidence that rocks on Mars did that recently, geologically speaking: about 625,000,000 years ago. This is a big deal for folks who have been trying to figure out what the Martian atmosphere was like in the Solar system's early years.
It's also evidence that water flowed on Mars within the last 700,000,000 years. Back then, Earth's climate was much colder than today's; and the earliest animals we've found so far, sponge-like critters called Otavia antiqua, were a newish sort of life here.
Even so, that's "recent," compared to the 4,540,000,000 years Earth and Mars have been around. It's quite possible, even probable, that Mars had more water in it's very early eras.
The Case of the Missing AtmosphereToday's Mars has a very thin atmosphere. Pressure at the surface is about six tenths of one percent of Earth's. That's enough for custom-designed parachutes and dust storms. The latter may make exploring Mars more difficult, it its own way, than exploring nearly-airless places like Earth's moon.
Mars is smaller than Earth, so more of its atmosphere could escape over the four and a half billion years since it formed. Earth-based astronomers confirmed that Mars had an atmosphere, which seemed to be much less substantial than our home world's.
But I don't think most scientists expected so little air on Mars.
One of the questions lately has been: what happened to the Martian atmosphere? It could have 'boiled off,' escaping into space, but although Mars is much smaller than Earth: it isn't that much smaller. Loss to space might be the answer, or not.
Analyses of the Lafayette meteorite adds evidence favoring another explanation.
The Martian atmosphere may still be on Mars: chemically locked in the planet's rocks.
From a 'pure science' viewpoint, this is a valid idea which can be tested. If verified, we have many more questions: starting with exactly how the Martian atmosphere got absorbed.
The Great Martian Land Rush?We don't have the technology, or the economic incentives, to colonize Mars. Not today, not quite. But we're getting closer.
Folks exploring Mars might be able to haul enough breathable air with them, using existing air recycling tech. That's a lot of material and equipment to haul over interplanetary distances. The job would be easier, and probably cheaper, if explorers could limit supplies to what's needed for deep space: and make their own air on-site.
If the Martian atmosphere is still there, chemically bound to rocks on or near the surface, 'all' explorers have to do is separate air from rocks. There's more to it than that, of course.
The atmosphere of Mars is mostly carbon dioxide now, and probably was in the planet's 'springtime.' The bad news is that we can't breath carbon dioxide. Actually, we can: but it doesn't do us much good. The good news is that carbon dioxide is made of two elements that we need and use: oxygen and carbon.
If explorers can extract breathable oxygen and the carbon that we and the food we eat need from Martian rocks, settlers can too.
The 'great Martian land rush' may not happen for decades, or centuries. But it's looking more like a practical idea and less like "science fiction" every year.
More about Martian carbon dioxide and all that:
- "Sequestration of Martian CO2 by mineral carbonation"
Tim Tomkinson, Martin R. Lee, Darren F. Mark & Caroline L. Smith; abstract; Nature Communications 4, Article number: 2662 (October 22, 2013)
(From Nature Communications, used w/o permission)
"Figure 3: Mars' H2O and C2 reservoirs and Amazonian secondary mineral formation."
(Nature Communications )
3. Trees With Gold in their Leaves
"There's Gold in Them Thar Trees"After the initial 'wow, that's interesting' impression, I realized that this story might easily get - misunderstood.
Charles Q. Choi, LiveScience (October 22, 2013)
"Trees may turn golden for reasons that have nothing to do with the onset of autumn: Eucalyptus trees can hold grains of gold, potentially helping reveal buried treasure, scientists now find.
"Many plants root deep into the Earth, drawing up nutrients and minerals they need for life. Researchers hope this fact could one day help miners unearth gold, especially since discoveries of new deposits of the precious metal have dropped 45 percent over the last 10 years.
"Scientists in Australia focused on eucalyptus trees, since traces of gold are sometimes found in soils surrounding these plants. However, researchers were not certain until now whether trees could actually absorb the precious metal from underground deposits or if the wind simply blew gold dust there from other sites...."
It may be only a matter of time before someone starts selling eucalyptus tree seeds and saplings: implying that planting them will make gold appear under your 'millionaire maker' tree. If whoever tries this is careful about what words they use, their enterprise might be legal.
There may already be made 'contains gold' eucalyptus leaves for sale somewhere, and adverting for products containing eucalyptus oil may play up the 'gold' angle. Advertising doesn't have to be deceptive, and that's another topic.
Eucalyptus Trees, Gold, and Getting a Grip
"...The researchers are not proposing mining these eucalyptus trees for gold, Lintern cautioned. 'The amount of gold in the trees is extremely small. You would need 500 trees or more growing over a gold deposit to have enough gold to make a ring.'Looks like I'm not the only one who thought about possible misunderstanding of this news. Harvesting leaves from that many trees to get under an ounce of gold doesn't seem to make sense, particularly since the gold would have to be sorted out from the leaves.
"Instead, eucalyptus trees could help miners identify where deeply buried gold deposits might be located and therefore avoid wasting time, money and resources hunting for the precious metal over vast tracts of land, Lintern said."
(Charles Q. Choi, LiveScience)
As 'prospectors,' though, eucalyptus trees make sense.
My guess is that since eucalyptus trees probably don't need gold, and 'excrete' what they absorb from the soil into their leaves. The article doesn't say, but that seems reasonable.
4. Habitable Zones and Kepler-69c: There's More to Learn
(Used w/o permission.)
Artist's rendering of Kepler-69c, as a super-Venus (left) and super-Earth (right).
"Super-Earth Planet Is More Like Super-Venus, NASA Says""A lot of unanswered questions" is, I think, an enormous understatement. A hundred years ago, the best information we had about other planets in the Solar system came from observations made through Earth's turbulent atmosphere.
Elizabeth Howell, Space.com 1 (October 21, 2013)
"An alien planet declared a super-Earth by NASA might not be so habitable after all. New measurements flag the planet (called Kepler-69c) as more of a 'super-Venus' that would likely be inhospitable to life.
"The planetary status change is part of a larger struggle over how to define the habitable zone of a star. In recent years, scientists determined that the distance between a planet and its type of star is just one metric that hints at the likelihood of liquid water on its surface, which could fuel life. Other factors include the planet's atmosphere and even how the star behaves.
" 'There are a lot of unanswered questions about habitability,' astrophysicist Lucianne Walkowicz, Kepler science team member at Princeton University, said in a statement...."
Today, we've landed robot explorers on Mars and Venus: and sent others to Mercury, Jupiter, Saturn, Uranus, Neptune, and beyond. Venus is hotter than we thought it would be, Mars has less air than many expected, and we've learned: that there's a very great deal yet to be learned.
Depending on a person's temperament, that could be frustrating, irrelevant, or fascinating. I'm one of the fascinated ones.
Kepler-69 System: Background
(NASA Ames/JPL-Caltech, used w/o permission.)
"The artist's concept depicts Kepler-69c, a super-Earth-size planet in the habitable zone of a star like our sun, located about 2,700 light-years from Earth in the constellation Cygnus.
"Kepler-69c, is 70 percent larger than ... Earth, and is the smallest yet found to orbit in the habitable zone of a sun-like star. Astronomers are uncertain about the composition of Kepler-69c, but its orbit of 242 days around a sun-like star resembles that of our neighboring planet Venus."
(NASA Ames/JPL-Caltech, used w/o permission.)
"The diagram compares the planets of the inner solar system to Kepler-69, a two-planet system about 2,700 light-years from Earth in the constellation Cygnus. The two planets of Kepler-69 orbit a star that belongs to the same class as our sun, called G-type.
"Kepler-69c, is 70 percent larger than the size of Earth, and is the smallest yet found to orbit in the habitable zone of a sun-like star. Astronomers are uncertain about the composition of Kepler-69c, but its orbit of 242 days around a sun-like star resembles that of our neighboring planet Venus. The companion planet, Kepler-69b, is just over twice the size of Earth and whizzes around its star once every 13 days.
"The artistic concepts of the Kepler-69 planets are the result of scientists and artists collaborating to help imagine the appearance of these distant worlds...."
More about the Kepler-69 system:
- "Kepler-69c: Super-Venus"
- "Kepler-50 and the Solar System"
Ames Research Center
- "NASA's Kepler Discovers Its Smallest 'Habitable Zone' Planets to Date"
NASA press release (April 18, 2013)
- "A super-Earth-sized planet orbiting in or near the habitable zone around Sun-like star"
Cornell University (April 17, 2013)
- "Oxygen, Life, and Autocells"
(October 18, 2013)
- "Life in the Universe, God, and Getting a Grip"
(October 17, 2013)
- "Life in the Universe: Learning Where to Look"
(September 20, 2013)
- "Exoplanets and Extraterrestrial Life: The Search Continues"
(September 6, 2013)
- "The Three Super-Earths of Gliese 677C; and Unexpected Planets"
(June 28, 2013)
1 CAUTION: Space.com was listed as an "attack website" October 24, 2013.
Rhis is the third such incident in the last 90 days:
- "Diagnostic page for www.space.com"
Safe Browsing, Google blogs
You may chose to click those links, but I do not recommend doing so this week. (October 25, 2013)
The links were safe when I visited them, previous to the latest incident. Although the links remain for your later convenience, I do not recommend using them until several days after the most recent "attack website" listing.
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