Friday, December 31, 2010

More Cracks

Four new cracks have appeared in the external tank of space shuttle Discovery. NASA says these cracks will be fixed using the same techniques applied to earlier cracks in the same tank.

This mission, the last for Discovery, was scheduled to go in early November, but weather problems, a gas leak, and the initial cracks in the tank delayed things. Launch is now scheduled for February 3, but that too might be pushed back.

Discovery seems in no hurry to go into retirement.

Thursday, December 30, 2010

Galaxy 15 Back Under Control

Galaxy 15, the communications satellite that went out of control last April and began wandering through the constellation of communications satellites, threatening havoc, came back under control last week. Engineers think the battery powering the satellite finally went dry, whereupon the onboard computer reset, as it was designed to do in such circumstances, and began accepting commands from the ground again.

Intelsat, owner of the satellite, has put it in safe mode until all its systems can be thoroughly checkd out. After that, a decision will be made as to whether Galaxy 15 can be returned to service. Engineers still don't know what made the satellite malfunction in the first place.

Wednesday, December 29, 2010

Dextre Checks Out

Dextre, the robotic astronaut assistant aboard ISS, successfully completed its final check out last week. The first real task for the two-armed robot will be next month. A Japanese cargo vessel will arrive, and Dextre will unload it and place two suites of equipment in their permanent positions.

Dextre is stationed on the outside of ISS and is designed to do some of the routine maintenance tasks that have been done up to now by spacewalking astronauts, thus relieving them of some more dangerous duty and freeing them to spend more time on more productive projects.

Tuesday, December 28, 2010

Exploring Titan

Mission planners studying ways to explore Saturn's magnificent moon Titan within the next few years are looking at several possibilities. The big element guiding their work involves deciding whether to try to cover a large area to get a broad overview, or, alternatively, study a smaller area in more detail.

If they choose the latter approach, the obvious choice would be to send a lander partnered with a rover. We know how to do that, but pulling it off on Titan would be a real challenge. For one thing, because of the distance between Earth and Titan, a rover there would either have to move extremely slowly, or it would need to be able to navigate and make decisions largely on its own-- in what is likely a more dynamic surface environment than the one on Mars, for example.

Covering a large area would require using aircraft; Titan's thick atmosphere allows a range of options. Lighter-than-air vehicles could fly high, studying the atmosphere, or fly under the haze layer to map large tracts of the surface. Hot-air balloon-type craft could also be used. Even jets are a possibility. A jet aircraft might be able to circumnavigate Titan at relatively low altitude in several hours.

Combining those two basic options might also be possible. A blimp or a balloon, for example, could drag an instrument package along the ground as it flew, thus sampling both sky and surface. Deciding exactly how best to go after Titan's mysteries in an era of extremely limited budgets will be at once a difficult and a fascinating exercise.

Monday, December 27, 2010

Noticing Novae

Scientists using data from a satellite meant to study the Sun and the solar wind have discovered four novae in the early stages of their eruptions. Only two of the stars were picked up by other means. A nova is the explosion of a white dwarf star. Not only doesn't the explosion destroy the star, but a single star can go nova several times. A supernova, on the other hand, does destroy the star, sometimes leaving a black hole.

The study suggests the astronomical community is missing many such events even when a nova reaches naked-eye visibility, resulting in an underestimation of the frequency of nova events in the universe. Dedicating an astronomical satellite to doing an all-sky survey every orbit of the Earth could pick up more nova explosions. The locations of those events could then be relayed to ground-based observatories for more detailed study. This seems to be a case in which a relatively modest program could produce important results.

Sunday, December 26, 2010

Indian Mishap

India's largest launch vehicle, the GSLV, malfunctioned Saturday shortly after liftoff and had to be destroyed. It was the second failed launch of the rocket this year.

The GSLV carried a huge communications satellite and had had to be modified to accomodate that size. Whether that modification contributed to the malfunction is not yet known. Whatever the cause turns out to be, the failure is a setback for the building space power. Historically, however, failures are relatively common in the development of new rockets. The Indians plan to push forward, though, on their emerging space program.

Friday, December 24, 2010

Alien Comets

A new study suggests that most of the comets now orbiting the Sun in fact originated in other star systems. The study tries to put a number on the comet population of the Oort Cloud, a huge shell around the Sun far beyond the orbit of Pluto, and comes up with 400 billion. Using the current model, which assumes virtually all comets are left over pieces from the formation of the Solar System, the number comes to only about 6 billion.

The huge discrepancy probably stems from the birth circumstances of the Sun, researchers say. Astronomers think the Sun developed in a loose star cluster that contained perhaps between one hundred and one thousand members. The cluster broke apart, of course, since the Sun now flies through space essentially alone, but while the stars were close, they could have traded comets, and the Sun could have acquired a huge retinue.

Astronomers generally argue that studying comets can tell us a lot about the early Solar System. If this new study is correct, studying comets could also shed light on the formation of other solar systems-- a remarkable bonus for science.

Thursday, December 23, 2010

Economics And Space Settlement

The economic situation in the world over the next few years may make the idea of settling space seem like a pipe dream. If part of the cure for our debt problem lies in creating a larger economy, however, expanding into space should be one engine harnessed.

Virtually all of the natural resources of the Solar System lie beyond Earth. We currently have the ability to begin resource-mapping other worlds as well as to assay asteroids-- and we have private, commercial firms building to meet the challenge of making profits directly from space operations. When that can be done, we should see an economic expansion rolling on indefinitely, creating a human economy no one today can imagine.

Can the same bunch of politicians and economists, essentially, that let the world economy nearly collapse now lay the legal and financial foundation that will support a vibrant economy that increasingly incorporates resources and products from beyond Earth? Over the next few years, that question will be answered.

Wednesday, December 22, 2010

Star of Bethlehem

Often this time of year, the American media runs a story about an astronomer trying to prove what the Star of Bethlehem actually was, or could have been. The usual suspects are a comet, a supernova, or a grouping of planets that had special astrological meaning. At the time, there were several cultures on Earth that had sophisticated understandings of the night sky, from the Chinese to the emerging civilizations in Mexico and South America. The people of that time were skywatchers.

None of those cultures seem to have recorded any remarkable stellar event around the time of Jesus' birth. Indeed, only one of the Gospels mentions the Star of Bethlehem. So, where does that leave the Christmas Story? There was a literary tradition in the cultures mixing in what is now called the Middle East at that time that the births of great men were marked by some event in the natural world. A new star sitting over a particular town would fit that tradition. The Gospels are not history in the way we understand history. They do seek to tell the story of a remarkable life, but they are also intent on making sure they convey just how remarkable that life was.

Does that mean there was no Star of Bethlehem? Certainly not. There are three basic options. There may have been a star noted around the world, but the passage of two thousand years has at least hidden the evidence. We might someday find that evidence, or we might not. Or, the Star may have been a beautiful, poetic, wholly legitimate literary device used to herald the beginning of a life that would change the world. Or, maybe the Star was exactly what the Christmas Story says it was, a sign from God that an extraordinary event had taken place. Perhaps it was not visible around the world because the initial Christian drama would play out only in Judea, on the eastern frontier of the Roman Empire, and the power of Christianity was to rest on faith, not evidence.

Whatever the truth, astronomers probably shouldn't be looked to as the group to figure it out just because a story involves a star.

Tuesday, December 21, 2010

Hollow Worlds

There seems to be a group of UFOlogists, or ancient astronaut theorists, or whatever they call themselves, that takes seriously the notion that the Earth and the Moon are hollow. Honest to God. They say the Moon is a gigantic interstellar spaceship put in orbit around Earth to allow its crew to monitor Earth, and they further hold that there are likely alien bases, living dinosaurs, and all manner of stuff inside our planet.

Of course, Newton's Laws of Gravity allow us to "weigh" worlds by observing their interactions with other bodies and plugging the data we get from that observation into Newton's equations. That approach has allowed astronomers to determine the masses of stars and galaxies across the universe, and it has allowed humans to navigate space probes across their home solar system with exquisite precision. It works, and it is an extraordinary testament to the power of the human mind.

Those same laws tell us the concept of a hollow Earth and Moon is nonsense. We have directly measured the density of the outer shells of both worlds, and we know precisely how they interact gravitationally. If they were hollow, that interaction would be different because they would be less massive. Hollows lack the mass of solid, compressed rock.

Alien visitation of Earth early in the human epoch is not impossible. Continued visitation to this day seems to stretch reality almost-- but not quite-- to the breaking point. Making such a case, therefore, is extremely difficult for the most serious, rational investigator. Allowing such fantasies as exotic, abundant life filling huge open spaces in a hollow Earth to go unchallenged only makes the fundamental task virtually impossible.

Monday, December 20, 2010

Cosmic Background Rings

When physicists accidentally discovered radiation pervading the universe at an extremely low energy level nearly five decades ago, it was taken as evidence of the Big Bang-- in fact, as roughly the echo of the event that gave birth to our universe.

Now, two physicists studying that cosmic background radiation have discovered a "ring" of radiation in the data. They interpret the ring as evidence of a universe before the Big Bang, or, alternatively, as evidence of universes beside our own. Most physicists have generally held that we will never know what existed before the Big Bang-- if indeed "before the Big Bang" has any meaning at all. Theoretical physicists do allow for the possibility of other universes, but, so far, that idea has lacked supporting data.

Other physicists acknowledge the ring is in the data, but they reject the exotic explanations. They say the data can tell us more about the organization of the early universe, perhaps even about the split-second between the Big Bang and the inflation of spacetime that led to the universe we know. History suggests the majority of competent scientists are right about most things in their expertise most of the time, but leaps forward are made when a scientist hits upon an idea that turns out to be revolutionary.

Sunday, December 19, 2010

Television News And Space

Television news has always had an odd relationship with the U. S. manned space program. During Mercury and Gemini, the networks of the day covered it extensively. There seemed to be a perfect match, after all-- television was a visual medium, and NASA provided remarkable visuals. Walter Cronkite and CBS, for example, also provided extraordinary coverage of the Apollo 11 mission, but by Apollo 13, the networks planned only limited coverage. That changed, of course, with the life-or-death battle Apollo 13 became, but subsequent Apollo missions again received limited live coverage-- as if every space mission is not a life-or-death battle.

The space shuttle program has operated in a different media environment. Cable news channels have meant anyone interested could see most or all shuttle launches live. Still, most were ignored by the major broadcast networks, and space policy was rarely addressed in a substantive way by either cable or broadcast news.

The same pattern was followed with the recent Falcon 9/Dragon launch-- limited coverage by the broadcast networks of an event that could mark a new era in the Space Age. The simplest explanation of that lack of interest, perhaps, is that the network news divisions don't understand the potential impact of private corporations operating space programs of their own. Why those vaunted divisions don't understand that when they do know who Kim Kardashian is lies beyond the scope of this blog. That it seems to be the case, however, is probably not a good sign for serious journalism at the network level. Such a situation would be unfortunate for the nation generally-- well beyond any effort to reach into space.

Saturday, December 18, 2010


The year 2010 did not see humanity's second manned mission to Jupiter, as it did in Arthur C. Clarke's novel centered on that year, but it may be remembered as a pivotal year in the history of mankind's move into space.

The year saw a shift in U. S. space policy, emphasizing technology development to build a foundation for deep space manned missions. It saw the continued maturation of unmanned programs around the world. China, India, and Japan had successful unmanned lunar missions, and Japan successfully returned samples from a comet to Earth. Several governments of major nations expressed interest in participating in an international program to build a lunar base.

Private space efforts continued gaining momentum, as well. The Google Lunar X-Prize competition gathered more teams; attempts to win the prize should commence very soon. Bigelow Aerospace and Boeing have joined to look at building private space stations and a transportation system to get people to them. Virgin Galactic is well into its test flight schedule for its commercial suborbital offering, and is already looking at orbital flights. Interorbital Systems is still planning a manned orbital flight launched from the sea off Tonga in a matter of months. SpaceX completed two successful test flights in 2010 of its projected workhorse launcher, the Falcon 9.

Several probes at Mars continue to provide data that deepens our understanding of that planet. Cassini continues to reveal marvels and mysteries in the system of Saturn. The year saw the number of exoplanets swell to over 500. With new appreciation of where life might thrive, new possibilities for finding life elsewhere in this solar system and beyond have opened up.

What 2011 may hold we can only wait and see.

Friday, December 17, 2010

Finding Your Own Planet

Scientists, for several years, have looked for ways to include the interested public in research projects online. The idea has been to foster understanding and enthusiasm for science while allowing investigators to get more done by utilizing thousands of volunteers.

The latest such project comes from the good folks at, and uses data from the Kepler planet-hunting spacecraft. Kepler searches for planets orbiting other stars by looking for transits-- times when a planet passes between Kepler and the planet's parent star. Such events cause dips in the amount of light from a star that reaches Kepler.

Finding a planet therefore becomes a pattern recognition problem. The human mind is very good at recognizing patterns. So, those who participate in this project will be given Kepler data to look through. If they find a pattern, they just might have found the latest exoplanet-- possibly even a new Earth. Of course, NASA will be doing the same thing, but it will be using powerful computers and custom-written software. Besides finding new worlds, finding out how the human mind fares against computers in this area should be interesting.

Thursday, December 16, 2010

Commercial Spaceships

Orbital Sciences Corporation is working with NASA to develop a "blended body" human-rated spaceship to transport people to and from low Earth orbit. Blended body vehicles are extremely aerodynamic, which strongly suggests OSC sees the craft as being able to maneuver in the atmosphere, probably land on a runway, and flying multiple missions. The spaceship would launch atop an Atlas 5 rocket. OSC has also contracted with Virgin Galactic to use VG's WhiteKnightTwo carrier aircraft in test flights of its blended body. VG has made it clear it intends to offer orbital flights in short order. A relationship with OSC's manned orbital spaceship program may be a step in that direction.

The Sierra Nevada Corporation, based in Reno, is also working with NASA to complete development of the company's DreamChaser. DreamChaser has had a difficult history, not least because of financial problems, but it might yet fly. DreamChaser is another spaceplane-type vehicle.

Four hundred miles or so down the highway from Reno sits Bigelow Aerospace. BA is looking for a way to get people to and from low Earth orbit regularly and relatively inexpensively so it can begin building space stations. If things go right, BA may soon see that problem solved.

Wednesday, December 15, 2010

Ice Volcano Likely On Titan

Scientists using Cassini data think they have solid evidence of at least one ice volcano (cryovolcano) on Saturn's huge, remarkable moon, Titan. Lava flows from terrestrial volcanoes, but ice volcanoes throw out water or water vapor, hydrocarbons, or other complex chemicals. Such geologic activity on Titan would also explain the amount of methane in Titan's atmosphere, as ice volcanism could replenish methane, which, over time, is broken down by radiation.

The existences of ice volcanoes-- if there's one, there's likely more-- also increases the odds of life existing on Titan by keeping the complex chemistry we see stirred up, and by connecting organic compounds on the surface and in the atmosphere to a possible underground sea of liquid water. That thinking-- always going back to life in liquid water-- may turn out to be too Earth-centric. Life on Titan, and other worlds, may be really alien, after all. Still, water is our starting place for now.

Tuesday, December 14, 2010

Space Superfund?

A new study suggests a fund similar to the U. S. Superfund designed to finance the cleanup of polluted sites be established to deal with the problem of space junk. The study calls for the generators of space junk, both nation-state and private concern, to contribute to such a fund, and for nation-states to acknowledge junk in orbit is a problem and to commit to limiting the amount of such junk, or debris, in the future.

Further, the study calls for the development of technologies that will allow the removal of debris from Earth orbit, and, importantly, the testing of such technologies in space. It notes that during the Gulf of Mexico oil spill last summer, for example, technologies to shut off the spill were present before the accident, but they hadn't been tested in that specific situation, and too many of them didn't work. Testing various approaches in space, therefore, is crucial to developing a suite of technologies that would actually work on the full range of different kinds of junk in orbit.

Monday, December 13, 2010

Saturn's Rings

Various theories have tried to explain the existence of Saturn's magnificent ring system. Even the age of the rings has been debated-- some theories hold the rings are essentially as old as the planet, for example, while others argue the rings are a transitory phenomenon which happens to be there at a time humans have telescopes and spacecraft. A new model suggests the rings are indeed old.

The model posits a Titan-sized moon smashed into Saturn perhaps 4.5 billion years ago. As the moon spiraled into the huge planet, Saturn's gravity ripped it apart. The outer, icy layers of the moon stayed in space while the core barreled into Saturn. This could have happened more than once, suggesting an explanation for why Saturn has only one moon of any real heft while Jupiter, for example, has four.

The ice that stayed in space, according to the model, formed the ring system, which originally was made of virtually pure water ice. The model doesn't stop there, however. It goes on to argue ice ripped away from the early big moon(s) eventually formed some of Saturn's small, icy moons, like Tethys, Enceladus, and Mimas. The comprehensive nature of the model no doubt deepens its appeal, but scientists could soon get some hard data to put against the model. Near the end of its mission, in 2017, the Cassini spacecraft will fly directly into the rings, getting the best information yet about their composition, structure, and dynamics.

Sunday, December 12, 2010

Krulwich And Armstrong

Robert Krulwich of NPR asked last week why Neil Armstrong and Buzz Aldrin didn't stay on the lunar surface longer and roam farther from the lunar module than they did during the Apollo 11 mission, which was the first manned landing on another world. Armstrong responded via e-mail, patiently explaining that no one had ever walked on the Moon before, NASA wasn't entirely sure what would happen, NASA wanted the astronauts to stay within the field of view of the single television camera the astronauts had set up-- and NASA wanted to get the men back safely. Armstrong went on to point out that subsequent Apollo astronauts did roam farther from their lunar modules.

Perhaps a good question is why Mr. Krulwich asked his question. Assuming any basic appreciation at all of the achievement of Apollo 11, a few moments of reflection should tell anyone why Armstrong and Aldrin didn't sprint across the lunar surface. Of course, journalists get paid to ask questions-- often provocative questions-- not necessarily to reflect. Still, Krulwich did enough research to note that the surface explorations of the two astronauts could fit within a football field, or a baseball diamond. Such research-- with all due respect to Mr. Krulwich-- misses the point. The relevant distances that are important in the story of Apollo 11 are the distance from Earth to the Moon, the last several thousand feet separating the closest approach to the Moon of Apollo 10's lunar module from the lunar surface, and the distance home.

Friday, December 10, 2010

NASA Spending

The U. S. House passed a spending bill this week that, among other things, provided NASA's 2011 budget. In a time that finds many Americans, and many members of Congress, clamoring for deep cuts in federal spending, NASA did fairly well in the spending bill, getting only $90 million less than President Obama requested.

The NASA-related provisions in the bill also officially cancels the Constellation program, replacing it with Mr. Obama's emphasis on technology development and strengthening the commercial space sector. That said, however, the bill also continues funding for the development of a heavy-lift vehicle for NASA as well as for continued development of the Orion capsule-- two of the biggest pieces of Constellation.

The bill now goes to the U. S. Senate for its consideration.

Thursday, December 9, 2010

Akatsuki Misses Venus

Japan's Akatsuki space probe was supposed to go into orbit around Venus December 6. Instead, there was a problem, and Akatsuki sailed right past the planet. The probe's rocket engine failed to fire long enough to insert the spacecraft into orbit.

The cause of the failure is not yet known. The rocket's nozzle could have been the problem, and there is also the possibility, however unlikely, that the spacecraft was hit by an object.

All is not completely lost for the mission, though. Akatsuki's current flightpath will take it back to Venus in 2016 or 2017. At that point, another attempt might be made to put Akatsuki into orbit around Venus and carry out its mission-- a detailed examination of the atmosphere of Venus with an eye towards explaining why that planet turned out so different than Earth.

Wednesday, December 8, 2010

Dragon Follow Up

After a successful launch this morning atop its Falcon 9, SpaceX's Dragon capsule orbited Earth, maneuvered in space, deployed a parachute to break it's re-entry speed, deployed three main parachutes, and splashed down in the target area in the Pacific.

SpaceX has thus become the first private company to retrieve a capsule it put into orbit. That is a huge step forward, not only for the company, but for those who argue private companies can in fact operate in space. The object now is to replicate the feat until it becomes boring and routine, but SpaceX has pulled it off on the first try. There is no reason to think it cannot become routine-- and when it does, the age of opening space to commercial enterprises will have well and truly begun.

Dragon Flies

Well, it looks like NASA was right. After delaying the first flight of the Falcon 9/Dragon configuration yesterday, SpaceX initially said the launch would not be attempted until Thursday at the earliest. NASA engineers said maybe Wednesday. In fact, Dragon is in low Earth orbit after a successful launch and a successful burn of the second stage rocket. This is the second consecutive successful launch of a Falcon 9-- itself a good achievement for a new company operating a new rocket system. If Dragon is recovered by SpaceX personnel after a splashdown in the Pacific as planned, that would be another first for a private company.

Tuesday, December 7, 2010

Dragon Flight Pushed Back

SpaceX has delayed the first test flight of its Falcon 9/Dragon configuration. Both the company and NASA say the flight could yet take place this week.

A final inspection before launch turned up possible problems with the nozzles of the second stage rocket engines. Depending on how serious the problems are, the flight could take place as early as Thursday, according to SpaceX, or as early as Wednesday, according to NASA. The difference in the estimate is interesting, and the fact that the difference was made public even more interesting. This time, the difference is probably not important, but NASA and its private partners might want to work out who speaks for a project early on in this new era.

Monday, December 6, 2010

SpaceX Ready To Rumble

All seems to be A-OK for the first flight of a dummy Dragon capsule atop its Falcon 9 launcher, according to SpaceX, the company building both Dragon and Falcon 9. The launch is scheduled for tomorrow morning from Cape Canaveral in Florida. Dragon is scheduled to splashdown in the Pacific perhaps four hours later, to be recovered by a SpaceX ship.

The Falcon 9-Dragon configuration is slated to service ISS after the space shuttle is retired by delivering cargo and carrying away garbage. SpaceX is also looking at man-rating Dragon so that it can also ferry humans to and from low Earth orbit.

Sunday, December 5, 2010

The Tiger Stripes Of Enceladus

Scientists have found over centuries, and especially over the most recent few decades, that the closer you look at Nature, the more there is to see, and the more complex Nature looks.

That situation held true again during Cassini's August flyby of the southern hemisphere of Saturn's moon Enceladus. The south polar region of Enceladus is the home of the famed erupting geysers, which in turn explode from cracks in the surface ice shell astronomers have dubbed "tiger stripes." The August flyby-- the closest to that area until 2015-- revealed the tiger stripes in unprecedented detail and showed a more intricate system of cracks than scientists had imagined. Smaller cracks branch from large cracks. While the tiger stripes are warmer than the surrounding surface, there are even warmer hot spots within the crack system. Possibly, such hot spots will host future geyser eruptions.

Of course, warm is relative on Enceladus, but the geyser spray includes organic compounds, which themselves argue for more heat and complexity under the surface. That the tiger stripes, in all their detail, suggest something like a fractal arrangement is further evidence that Nature is infinitely subtle.

Friday, December 3, 2010

Arsenic Instead Of Phosphorus

NASA researcher Felise Wolf-Simon has discovered a strain of bacteria that can replace phosphorus-- which heretofore biologists have thought was essential for life-- with arsenic and continue to thrive. Yes, arsenic-- Agatha Christie's favorite poison. Phosphorus and arsenic are closely related chemically, which likely accounts for the bacteria's ability to switch them, but the discovery is still a game changer.

This discovery once again widens the parameters of life, a process that has been continuing for the past couple decades at least. When life was found around volcanic vents deep in the ocean, it became obvious life could exist over a wider range of environments than scientists had imagined. Since then, life has been found in various supposedly inhospitable places on Earth, including deep inside nuclear power plants, bathed in what should be lethal radiation. As that is not a natural environment, and has in fact existed for only a few decades, bacteria inside nuclear facilities might tell us something about how quickly evolution can move.

Wolf-Simon's discovery clearly has major implications for the search for alien life, as well. Life-as-we-know-it may be a woefully inadequate yardstick. Why wouldn't it be? If we assume life evolves according to local conditions, assuming further that life elsewhere would be built on the same base as Earth life seems a bit odd. Arsenic instead of phosphorus is likely one more step towards realizing the infinite complexity of the universe.

Thursday, December 2, 2010

Body Bigger Than Jupiter?

Scientists are speculating that the outer Oort Cloud may contain more than comets. In fact, it might be home to a bruiser of a world, one up to four times more massive than Jupiter.

Scientists have noted there seems to be a pattern in the timing of mass extinctions on Earth, and they have tied one of those events-- the one that ended the Age of the Dinosaurs-- to a huge comet impact. The idea is that the pattern in mass extinctions might be explained by the Earth being struck periodically. That would require a trigger-- a big body out at the edge of the Solar System that alters the orbits of comets on something like a regular basis, sending them into the inner System. Astronomers studying the orbits of some comets think they have evidence of such a body. Similarly, astronomers mathematically inferred the existence and position of Neptune, leading to its optical discovery, by studying quirks in the orbit of Uranus.

The reason such a world has never been seen or photographed, they say, involves its incredible distance from the Sun. It would be too cold to be imaged in infrared, and receive too little sunlight to be seen in visual light. How a body so huge could form that far out remains a puzzle. Most stars like the Sun do have stellar companions, however, so this object, if it exists, could be a companion that didn't quite reach stardom.

Wednesday, December 1, 2010

Red Dwarfs

A team of astronomers is now proposing that there may be as many as three times the number of red dwarf stars as previously thought. Such stars are what the name suggests-- stars only a fraction of the Sun's mass that shine only feebly, hence the low energy red hue.

Astronomers already knew that red dwarfs were the most common star in the universe; this new number only solidifies that position. The increased number affects two important areas of study, however. First, three times as many as these stars in the universe adds a huge amount of mass, thereby reducing the amount of "dark matter" needed to account for the calculated masses of many galaxies.

Second, though red dwarfs shine only feebly, they do so for incredibly long time periods. They are also incredibly stable. Such lifespans and stability make them candidates for supporting life. It's true, their weakness would make their habitable zones extremely narrow and extremely close to the star, but given the red dwarf population in the universe and their long, stable lives, the odds are probably good that some of them support life.

Some may also support branches of civilizations that arose on planets circling other stars. The number and qualities of red dwarfs might make them attractive targets for civilizations that embrace interstellar travel as a way of expanding beyond their home solar systems. Such societies could place colonies in the habitable zones of red dwarfs, where they could potentially perk along for billions of calm, stable years.