December 30, 2010

NASA Scientist Publishes ‘Colonizing the Red Planet,’ a How-To Guide

A conceptual illustration depicts what a manned mission to Mars may look like. (NASA)

A conceptual illustration depicts what a manned mission to Mars may look like. (NASA)

A manned mission to Mars would be the greatest adventure in the history of the human race. And one man knows how to make it a reality. In fact, he just wrote the book on it — literally.

Joel Levine, senior research scientist with NASA’s Langley Research Center and co-chair of NASA’s Human Exploration of Mars Science Analysis Group, just published “The Human Mission to Mars: Colonizing the Red Planet.” The book reads like a who’s who of Mars mission science, featuring senators, astronauts, astrophysicists, geologists and more on getting to Mars, studying its atmosphere and climate, the psychological and medical effects on the crew and other details.

There’s even a section detailing the science of sex on Mars, should NASA attempt to create a permanent colony there.

“For the last three years, I’ve been co-chairing a panel of about 30 U.S. and Canadian scientists, coming up with a blueprint, purely from a scientific perspective, of humanity’s role on Mars,” Levine told He was asked to put together a special edition of the Journal of Cosmology exploring the topic, which was just published as the new book.

“The United States of America is the only country that can do this successfully right now,” he said. And to remain the technological leader of the world, he argued, we need to do this. And it’s quite possible, the book notes; after all, a trip to Mars isn’t even a lengthy one.

The trip to Mars would take on the order of 220 days using today’s chemical
propulsion technology,” writes Steven A. Hawley, a former astronaut now with the department of physics and astronomy at the University of Kansas, in a chapter on the challenges and sacrifices of the trip to Mars. He suggests either a short duration or longer duration stay before the return trip. “The longer surface mission would enable significant science, but also expose the crew to greater risk if systems don’t function as planned.

But regardless of whether a colony is initially established, Levine is passionate — and poetic — about a trip to Mars. “When we do this, the human species will be a two-planet species for the first time ever,” he said. A trip to Mars would open up countless revelations and possibly answer one of the greatest questions science today seeks to answer: is there life elsewhere in the universe?

“The search for life outside the Earth is one of the key questions in all of science,” he told, “and of all the objects in the Solar System, Mars is the most likely.”

Many scientists speculate that life may exist on the red planet today in the form of microorganisms, and the book concludes that a manned mission could very well answer that question for once and all. “All of the articles here conclude that yes, it’s possible that when we go to Mars we will find microorganism at the surface or below the surface.”

Another question Levine believes the mission will answer deals with the strange history of Mars — which he called the most intriguing, and the most confusing planet in the solar system. Today Mars has no liquid water and a very, very thin atmosphere — it’s like the Earth’s atmosphere at 100,000 feet, he said. Yet we have very, very strong evidence that its surface used to be covered with water. What happened to it all?

“What catastrophic event led to Mars going from an Earth-like planet to a very inhospitable planet today?” he asked. The Mars mission would send humans there to study that, and see if there’s a lesson in the planet for the future of Earth.

Levine has a general timeline in mind for the mission, which he hopes to launch by 2040. He believes we could launch the missions far sooner, however — if we could afford to. Tragically, the major problem for getting humans to Mars isn’t building new spacecraft, furthering science, or inventing new technologies, he says.

The only hold-up is the budget.

“NASA’s budget is 18 billion a year, and I don’t think we can seriously plan a launch until 2040” given those funds, he said. “If NASA’s budget went up 3 billion a year, or 5 billion a year, we could do it in half the time.”

But Levine presents a solution for that problem in his book as well, something unprecedented for NASA: advertising.

“The suggestion is marketing to different corporations and professional sports leagues for advertising, which is something NASA never does — it’s a whole new economic plan for financing what has to be the greatest adventure in the history of the human race.”


December 17, 2010

Beam Me Up: ‘Teleportation’ Is Year’s Biggest Breakthrough

Filed under: Cool, Space Exploration, Wierd — bferrari @ 1:23 pm
Crew members on the Starship Enterprise beamed to alien planets via teleporters. Now scientists are perfecting a way to communicate via a similar technology.  (NBC)

Crew members on the Starship Enterprise beamed to alien planets via teleporters. Now scientists are perfecting a way to communicate via a similar technology. (NBC)

Thanks to physics, and the truly bizarre quirks of quarks, those Star Trek style teleporters may be more than fiction.

A strange discovery by quantum physicists at the University of California Santa Barbara means that an object you can see in front of you may exist simultaneously in a parallel universe — a multi-state condition that has scientists theorizing that teleportation or even time travel may be much more than just the plaything of science fiction writers.

Until this year, all human-made objects have moved according to the laws of classical mechanics, the rules governing ordinary objects. Toss a ball in the air and it falls back to Earth. Drop a coin from your roof and it falls into your yard. But back in March, a group of researchers designed a gadget that moves in ways that can only be described by quantum mechanics — the set of rules that governs the behavior of tiny things like molecules, atoms, and subatomic particles.

And the implication — that teleportation and even time travel may someday, somehow be a reality — is so groundbreaking that Science magazine has labelled it the most significant scientific advance of 2010.

Physicists Andrew Cleland and John Martinis from the University of California at Santa Barbara and their colleagues designed the machine — a tiny metal paddle just barely visible to the naked eye — and coaxed it into dancing with a quantum groove: First, they cooled the paddle until it reached its “ground state,” or the lowest energy state permitted by the laws of quantum mechanics (a goal long-sought by physicists). Then they raised the widget’s energy by a single quantum to produce a purely quantum-mechanical state of motion.

They even managed to put the gadget in both states at once, so that it literally vibrated a little and a lot at the same time — a bizarre phenomenon allowed by the weird rules of quantum mechanics.

“When you observe something in one state, one theory is it split the universe into two parts,” Cleland told at the time, trying to explain how there can be multiple universes and we can see only one of them.

Crazy? Maybe. Insanely great science? Absolutely.

Science magazine has just recognized this first quantum machine as the 2010 Breakthrough of the Year. The magazine’s editors have also compiled nine other important scientific accomplishments from this past year into a top ten list, appearing in a special feature in the journal’s current issue.

“On a conceptual level that’s cool because it extends quantum mechanics into a whole new realm,” said Adrian Cho, a news writer for Science. “On a practical level, it opens up a variety of possibilities ranging from new experiments that meld quantum control over light, electrical currents and motion to, perhaps someday, tests of the bounds of quantum mechanics and our sense of reality.”

Science’s list of the nine other groundbreaking achievements from 2010 follows.

Synthetic Biology: In a defining moment for biology and biotechnology, researchers built a synthetic genome and used it to transform the identity of a bacterium. The genome replaced the bacterium’s DNA so that it produced a new set of proteins—an achievement that prompted a Congressional hearing on synthetic biology. In the future, researchers envision synthetic genomes that are custom-built to generate biofuels, pharmaceuticals or other useful chemicals.

Neandertal Genome: Researchers sequenced the Neandertal genome from the bones of three female Neandertals who lived in Croatia sometime between 38,000 and 44,000 years ago. New methods of sequencing degraded fragments of DNA allowed scientists to make the first direct comparisons between the modern human genome and that of our Neandertal ancestors.

HIV Prophylaxis: Two HIV prevention trials of different, novel strategies reported unequivocal success: A vaginal gel that contains the anti-HIV drug tenofovir reduced HIV infections in women by 39 percent and an oral pre-exposure prophylaxis led to 43.8 fewer HIV infections in a group of men and transgender women who have sex with men.

Exome Sequencing/Rare Disease Genes: By sequencing just the exons of a genome, or the tiny portion that actually codes for proteins, researchers who study rare inherited diseases caused by a single, flawed gene were able to identify specific mutations underlying at least a dozen diseases.

Molecular Dynamics Simulations: Simulating the gyrations that proteins make as they fold has been a combinatorial nightmare. Now, researchers have harnessed the power of one of the world’s most powerful computers to track the motions of atoms in a small, folding protein for a length of time 100 times longer than any previous efforts.

Quantum Simulator: To describe what they see in the lab, physicists cook up theories based on equations. Those equations can be fiendishly hard to solve. This year, though, researchers found a short-cut by making quantum simulators—artificial crystals in which spots of laser light play the role of ions and atoms trapped in the light stand in for electrons. The devices provide quick answers to theoretical problems in condensed matter physics and they might eventually help solve mysteries such as superconductivity.

Next-Generation Genomics: Faster and cheaper sequencing technologies are enabling very large-scale studies of both ancient and modern DNA. The 1,000 Genomes Project, for example, has already identified much of the genome variation that makes us uniquely human—and other projects in the works are set to reveal much more of the genome’s function.

RNA Reprogramming: Reprogramming cells—turning back their developmental clocks to make them behave like unspecialized “stem cells” in an embryo—has become a standard lab technique for studying diseases and development. This year, researchers found a way to do it using synthetic RNA. Compared with previous methods, the new technique is twice as fast, 100 times as efficient and potentially safer for therapeutic use.

The Return of the Rat: Mice rule the world of laboratory animals, but for many purposes researchers would rather use rats. Rats are easier to work with and anatomically more similar to human beings; their big drawback is that methods used to make “knockout mice”—animals tailored for research by having specific genes precisely disabled—don’t work for rats. A flurry of research this year, however, promises to bring “knockout rats” to labs in a big way.


December 15, 2010

Voyager 1 Leaves Sun’s Embrace, Nears Edge of Solar System

Filed under: Cool, Cosmology, Outer Solar System, Space Exploration, Space Ships — bferrari @ 2:40 pm

The Voyager 1 spacecraft, currently hurling through space at 38,000 mph -- and nearing the edge of the solar system.

The Voyager 1 spacecraft, currently hurling through space at 38,000 mph -- and nearing the edge of the solar system.

OUTER SPACE –  NASA‘s long-running Voyager 1 spacecraft is barreling its way toward the edge of the solar system.

Since 2004, the unmanned probe has been exploring a region of space where solar wind — a stream of charged particles spewing from the sun at 1 million miles per hour — slows abruptly and crashes into the thin gas between stars.

NASA said Monday that recent readings show the average outward speed of the solar wind has slowed to zero, meaning the spacecraft is nearing ever closer to the solar system’s edge to a boundary known as the heliopause.

“It’s telling us the heliopause is not too far ahead,” said project scientist Edward Stone of the NASA Jet Propulsion Laboratory.

Scientists estimate it will take another four years before Voyager 1 completely exits the solar system and enters interstellar space.

The latest milestone occurred in June when scientists noticed the solar wind speed matched the spacecraft’s. Just as wind velocity on Earth can vary, the team took measurements for several more months to make sure there were no changes.

“We knew this was going to happen. The question was when,” Stone said.

The Voyager results will be presented Tuesday at the American Geophysical Union meeting in San Francisco.

Launched in 1977, the nuclear-powered Voyager 1 and its twin Voyager 2 toured the planets and kept going in different directions. Voyager 1 veered north while Voyager 2 headed south.

Hurtling at 38,000 mph, Voyager 1 is currently 10.8 billion miles from the sun. Voyager 2 is traveling slower at 35,000 mph and is 8.8 billion miles from the sun.

When Voyager 1 finally exits the solar system, scientists expect to see a telltale change in the wind. Interstellar wind is slower, colder and denser than solar wind.

The Sun's Heliosphere

The Sun's Heliosphere

Navy Sets World Record With Incredible, Sci-Fi Weapon

Filed under: Cool, Gadgets, Government Policies, Military — bferrari @ 2:34 pm

U.S. Navy engineers at the Office of Naval Research prepared and test-fired a slug from their rail gun in a 2008 test firing. On Friday, December 9, the ONR will attempt to break its own record.

U.S. Navy engineers at the Office of Naval Research prepared and test-fired a slug from their rail gun in a 2008 test firing. On Friday, December 9, the ONR will attempt to break its own record.

A theoretical dream for decades, the railgun is unlike any other weapon used in warfare. And it’s quite real too, as the U.S. Navy has proven in a record-setting test today in Dahlgren, VA.

Rather than relying on a explosion to fire a projectile, the technology uses an electomagnetic current to accelerate a non-explosive bullet at several times the speed of sound. The conductive projectile zips along a set of electrically charged parallel rails and out of the barrel at speeds up to Mach 7.

The result: a weapon that can hit a target 100 miles or more away within minutes.

“It’s an over-used term, but it really changes several games,” Rear Admiral Nevin P. Carr, Jr., the chief of Naval Research, told prior to the test.

For a generation raised on shoot-’em-up video games, the word “railgun” invokes sci-fi images of an impossibly destructive weapon annihilating monsters and aliens. But the railgun is nonetheless very real.

An electromagnetic railgun offers a velocity previously unattainable in a conventional weapon, speeds that are incredibly powerful on their own. In fact, since the projectile doesn’t have any explosives itself, it relies upon that kinetic energy to do damage. And at 11 a.m. today, the Navy produced a 33-megajoule firing — more than three times the previous record set by the Navy in 2008.

“It bursts radially, but it’s hard to quantify,” said Roger Ellis, electromagnetic railgun program manager with the Office of Naval Research. To convey a sense of just how much damage, Ellis told that the big guns on the deck of a warship are measured by their muzzle energy in megajoules. A single megajoule is roughly equivalent to a 1-ton car traveling at 100 mph. Multiple that by 33 and you get a picture of what would happen when such a weapon hits a target.

Ellis says the Navy has invested about $211 million in the program since 2005, since the railgun provides many significant advantages over convention weapons. For one thing, a railgun offers 2 to 3 times the velocity of a conventional big gun, so that it can hit its target within 6 minutes. By contrast, a guided cruise missile travels at subsonic speeds, meaning that the intended target could be gone by the time it reaches its destination.

Furthermore, current U.S. Navy guns can only reach targets about 13 miles away. The railgun being tested today could reach an enemy 100 miles away. And with current GPS guidance systems it could do so with pinpoint accuracy. The Navy hopes to eventually extend the range beyond 200 miles.

“We’re also eliminating explosives from the ship, which brings significant safety benefits and logistical benefits,” Ellis said. In other words, there is less danger of an unintended explosion onboard, particularly should such a vessel come under attack.

Indeed, a railgun could be used to inflict just such harm on another vessel.

Admiral Carr, who calls the railgun a “disruptive technology,” said that not only would a railgun-equipped ship have to carry few if any large explosive warheads, but it could use its enemies own warheads against them. He envisions being able to aim a railgun directly at a magazine on an enemy ship and “let his explosives be your explosives.”

There’s also a cost and logistical benefit associated with railguns. For example, a single Tomahawk cruise missile costs roughly $600,000. A non-explosive guided railgun projectile could cost much less. And a ship could carry many more, reducing the logistical problems of delivering more weapons to a ship in battle. For these reasons, Admiral Carr sees the railgun as even changing the strategic and tactical assumptions of warfare in the future.

The Navy still has a distance to go, however, before the railgun test becomes a working onboard weapon. Technically, Ellis says they’ve already overcome several hurdles. The guns themselves generate a terrific amount of heat — enough to melt the rails inside the barrel — and power — enough to force the rails apart, destroying the gun and the barrel in the process.

The projectile is no cannon ball, either. At speeds well above the sound barrier, aerodynamics and special materials must be considered so that it isn’t destroyed coming out of the barrel or by heat as it travels at such terrific speeds.

Then there’s question of electrical requirements. Up until recently, those requirements simply weren’t practical. However, the naval researchers believe they can solve that issue using newer Navy ships and capacitors to build up the charge necessary to blast a railgun projectile out at supersonic speeds. Ellis says they hope to be able to shoot 6 to 12 rounds per minute, “but we’re not there yet.”

So when will the railgun become a working weapon? Both Ellis and Carr expect fully functional railguns on the decks of U.S. Navy ships in the 2025 time frame.


December 4, 2010

First Landing Photos: Secret X-37B Robot Space Plane Lands in CA

Filed under: Cool, Earth, Government Policies, Military, Space Ships — bferrari @ 4:29 pm

The U.S. Air Force’s mysterious X-37B robot space plane returned to Earth today (Dec. 3) with a successful landing at Vandenberg Air Force Base in California before sunrise.

Air Force officials hailed the unmanned X-37B space plane’s successful landing, though its mission remains shrouded in secrecy because of its classified nature. But Vandenberg’s 30th Space Wing did not shy from snapping photos of the X-37B vehicle, known as the Orbital Test Vehicle 1. Take a look at those first photos below:

More here.

December 3, 2010

NASA Hasn’t Found Alien Life, But Arsenic Microbe Still ‘Phenomenal’

Filed under: Cool, Cosmology, Extraterrestrial Life, Life, Wierd — bferrari @ 8:17 am
A scanning-electron micrograph image of arsenic-eating bacteria, which NASA says has redefined the quest for life in the universe.

A scanning-electron micrograph image of arsenic-eating bacteria, which NASA says has redefined the quest for life in the universe.

Scientists haven’t yet found E.T., but the discovery of an Earth microbe that thrives on arsenic should greatly broaden the search for life beyond Earth, NASA announced today (Dec. 2).

In a much-anticipated press conference, NASA announced that the bacterium GFAJ-1, found in a briny California lake, doesn’t just tolerate arsenic — it can incorporate the poisonous stuff into its DNA and other vital molecules in place of the usual phosphorus.

“We’ve cracked open the door to what’s possible for life elsewhere in the universe,” said study lead author Felisa Wolfe-Simon, NASA astrobiology research fellow at the U.S. Geological Survey in Menlo Park, Calif. “What else might we find? What else might we want to look for?”

NASA sent out alerts for the conference on Monday (Nov. 29), setting the Internet abuzz with speculation and rumors that life beyond Earth had been found, perhaps on Titan, Saturn’s largest moon. The actual discovery — which is very much terrestrial — falls short of those expectations, dashing the hopes of some who may have let their imaginations run wild.

“I’m sorry if they’re disappointed,” Mary Voytek, director of NASA’s astrobiology program, told reporters today. “But this is a huge deal. This is a phenomenal finding.”

Science fact looks like fiction

Scientists had regarded phosphorus as one of six key ingredients — along with carbon, hydrogen, nitrogen, oxygen and sulfur — that all life on Earth needs to survive.

So finding a microbe that substitutes arsenic for phosphorus is like coming face to face with the fictional Horta beast from the science-fiction TV show “Star Trek,” one of the scientists said. The Horta was based on silicon rather than carbon.

“In our mind, this is the equivalent,” Voytek said. “It will fundamentally change the way we define life, and perhaps the way we look for it.”

Search for extraterrestrial life

In particular, scientists hunting for life on Titan, Mars and other bodies throughout the solar system and beyond should open their minds, according to researchers. For if some life-forms on Earth are doing something so radically different, who knows what alien life might look like? [The Weirdest Life on Earth]

“The implication is that we still don’t know everything there is to know about what may make a habitable environment,” said astrobiologist Pamela Conrad of NASA’s Goddard Space Flight Center in Greenbelt, Md. “It opens up our perspective.”

The discovery also stresses that researchers shouldn’t focus narrowly on looking for signatures of certain molecules, Conrad added. Rather, they should assess a variety of variables at any particular site.

As an example, arsenic may be a more likely life ingredient than phosphorus in certain environments, such as Titan, researchers said. Titan is so cold — temperatures average minus 290 degrees Fahrenheit (minus 179 degrees Celsius) — that stable molecules like phosphate might not be reactive enough to help generate or sustain life.

Phosphate, a molecule composed of phosphorus and oxygen, is a key ingredient in the DNA of “normal” life. In the weird bacterium, the much more unstable arsenate apparently can take its place.

On Titan, “you might well want to have the increased reactivity of arsenate,” said biochemist Steven Benner of the Foundation for Applied Molecular Evolution in Gainesville, Fla., during the press conference.

Benner made the skeptic’s case against the new discovery, saying he thinks arsenate is likely too unstable to have been truly incorporated into the bacterium’s DNA.

A second genesis?

The arsenic-munching bacterium can utilize phosphorus as well as arsenic. In fact, it grows faster when given phosphorus. So it’s probably just extremely adaptable, not a life-form so fundamentally different as to belong to an entirely separate tree of life, researchers said.

But such organisms may be out there, waiting to be found. If such a “shadow biosphere” exists — if life has truly evolved more than once on Earth — that implies that life isn’t so special, that it can take root fairly easily. So the odds of life existing elsewhere in the universe would shoot up.

That’s just speculation — for now. The study does open scientists’ eyes to new possibilities, suggesting that life can assume more various forms — and live in a wider variety of places — than previously thought, researchers said.

So it’s important to make sure life-hunting probes are flexible — able to explore many different environments and to look for many different molecules, researchers said. That way, future probes could reduce the chances of overlooking evidence of alien life simply because it appears in a form that is completely unexpected.

“You would hate to go somewhere and not find it,” Conrad said.


December 1, 2010

Scientists Find 200 Sextillion More Stars in the Sky

Filed under: Cool, Cosmology, Exoplanets, Extraterrestrial Life, Space Exploration — bferrari @ 8:41 pm


The night sky may be a lot starrier than we thought.

A study suggests the universe could have triple the number of stars scientists previously calculated. For those of you counting at home, the new estimate is 300,000,000,000,000,000,000,000. That’s 300 sextillion.

The study questions a key assumption that astronomers often use: that most galaxies have the same properties as our Milky Way. And that’s creating a bit of a stink among astronomers who want a more orderly cosmos.

It’s one of two studies being published online Wednesday in the journal Nature that focus on red dwarf stars, the most common stars in the universe. The study that offers the new estimate on stars is led by a Yale University astronomer. He calculates that there are far more red dwarfs than previously thought, and that inflates the total star count.

A second study led by a Harvard University scientist focuses on a distant “super Earth” planet and sees clues to the content of its atmosphere — the first of this kind of data for this size planet. It orbits a red dwarf.

Red dwarf stars — about a fifth the size of our sun — burn slowly and last much longer than the bigger, brighter stars, such as the sun in the center of our solar system, said Yale astronomer

Pieter van Dokkum. His study looks at how many red dwarfs are in elliptical-shaped galaxies.

When scientists had estimated previously how many stars there were in the universe, they assumed that all galaxies had the same ratio of dwarf stars as in our galaxy, which is spiral-shaped. Much of our understanding of the universe is based on observations inside our Milky Way and then extrapolated to other galaxies.

But about one-third of the galaxies in the universe are not spiral, but elliptical, and van Dokkum found they aren’t really made up the same way as ours.

Using the Keck telescope in Hawaii, van Dokkum and a colleague gazed into eight other distant, but elliptical, galaxies and looked at their hard-to-differentiate light signatures. The scientists calculated that elliptical galaxies have more of those dwarf stars. A lot more.

“We’re seeing 10 or 20 times more stars than we expected,” van Dokkum said. By his calculations, that triples the number of estimated stars from 100 sextillion to 300 sextillion.

For the past month, astronomers have been buzzing about van Dokkum’s findings, and many aren’t too happy about it, said astronomer Richard Ellis of the California Institute of Technology.

Van Dokkum’s paper challenges the assumption of “a more orderly universe” and gives credence to “the idea that the universe is more complicated than we think,” Ellis said. “It’s a little alarmist.”

Ellis said it is too early to tell if van Dokkum is right or wrong, but it is shaking up the field “like a cat among pigeons.”

Van Dokkum agreed, saying, “Frankly, it’s a big pain.”

Ellis said the new study does make sense. Its biggest weakness might be its assumption that the chemical composition of dwarf stars is the same in elliptical galaxies as in the Milky Way. That might be wrong, Ellis said. Even if it is, it would mean there are only five times more red dwarf stars in elliptical galaxies than scientists previously thought, instead of 10 or 20, van Dokkum said.

Slightly closer to home, at least in our own galaxy, one dwarf star has astronomers at Harvard taking another step in their search for life. They were able to home in on the atmosphere of a planet circling that star using the European Southern Observatory’s Very Large Telescope in Chile. The planet lives up to the word alien.

Their paper reports that this giant planet’s atmosphere is either dense with sizzling water vapor like a souped-up steam bath, or it’s full of hazy, choking hydrogen and helium clouds with a slightly blue tint. The latter is more likely, say the researchers and others not involved in the study.

While scientists have been able to figure out the atmosphere of gas giants the size of Jupiter or bigger, this is a first for the type of planet called a super Earth — something with a mass 2 to 10 times Earth’s. It is more comparable to Neptune and circles a star about 42 light years from Earth. A light year is nearly 6 trillion miles.

And while this planet is nowhere near livable — it’s about 440 degrees (about 225 degrees Celsius) — characterizing its atmosphere is a big step toward understanding potentially habitable planets outside our solar system, said study chief author Jacob Bean at the Harvard Smithsonian Center for Astrophysics.

“You wouldn’t want to be there. It would be unpleasant,” said study co-author Eliza Kempton of the University of California Santa Clara.

Bean and Kempton looked at the light spectrum signature from the large planet as it passed in front of the dwarf star, and the result led to two possible conclusions: steam bath or haze.

The steam bath is the more interesting possibility because water is key to life, said outside scientist Alan Boss of the Carnegie Institution of Washington.

But an upcoming and still unpublished study by Kempton and Bryce Croll at the University of Toronto points more toward a hydrogen-helium atmosphere, several astronomers said.


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