NASA will unveil new discoveries this week that involve alien oceans in Earth’s solar system, space agency officials announced today (April 10).
On Thursday, April 13, NASA will hold a press conference that will “discuss new results about ocean worlds in our solar system,” according to a press release from the agency. The discovery will involve findings from the Hubble Space Telescope and NASA’s Cassini spacecraft, which is orbiting Saturn.
“These new discoveries will help inform ocean world exploration — including NASA’s upcoming Europa Clipper mission planned for launch in the 2020s — and the broader search for life beyond Earth,” NASA officials wrote in the same press release.
NASA’s ocean worlds press conference will begin at 2 p.m. EDT (1800 GMT) on Thursday and include a question-and-answer session with a panel of scientists from the Cassini and Hubble missions, as well as NASA’s planetary exploration and science directorates.
Those speakers include:
- Thomas Zurbuchen, associate administrator, Science Mission Directorate at NASA Headquarters in Washington;
- Jim Green, director, Planetary Science Division at NASA Headquarters;
- Mary Voytek, astrobiology senior scientist at NASA Headquarters;
- Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California;
- Hunter Waite, Cassini Ion and Neutral Mass Spectrometer team lead at the Southwest Research Institute (SwRI) in San Antonio;
- Chris Glein, Cassini INMS team associate at SwRI;
- William Sparks, astronomer with the Space Telescope Science Institute in Baltimore.
“Members of the public also can ask questions during the briefing using #AskNASA,” NASA officials wrote.
NASA’s Cassini spacecraft has been orbiting Saturn since 2004 to make detailed observations of the ringed planet and its many moons. The spacecraft is scheduled to end its mission on Sept. 15 with a fiery plunge into Saturn itself to avoid contaminating the planet’s icy moons, NASA officials have said.
The Hubble Space Telescope, meanwhile, has been in orbit around Earth since 1990 and has captured spectacular images of the universe, including of some solar system planets, during its mission. Last week, NASA unveiled amazing new images of Jupiter as seen by Hubble as the giant planet approached opposition (its closest point to Earth for 2017) on April 7.
There’s a good reason humanity hasn’t yet seen pictures of an Earth-like exoplanet. Getting such an image is not as easy as pointing a telescope at a distant star and snapping a photo. A tremendous amount of scientific work goes into isolating a clear image of a planet outside this solar system.
Earthlings have actually never seen exoplanets like the planets in our own solar system in light visible to human eyeballs. But scientists have obtained several images of distant, young gas giants in the infrared. Young gas giants are easier to photograph, because they’re much bigger than rocky planets and give off light as they cool down from formation.
Here’s an infrared image of the HR 8799 system, as seen by the Keck telescope. You can see four planets orbiting the star.
While it looks simple, in reality, an image like this probably took weeks or months to produce after scientists obtained the data. During that time, astronomers sifted through mountains of data, trying to separate the signals from the noise. It would have taken countless hours for the researchers to safely determine that those bright little dots are indeed planets.
What causes all that noise? It depends on if your telescope is space- or ground-based, but each type brings its own challenges.
I work at the Steward Observatory at the University of Arizona. My specialty is adaptive optics, which is basically the science involved in making pictures clearer. When looking at distant objects, we need images to have really high resolution. Most people think about resolution as the number of pixels on a screen. But in astronomy, it has a very specific definition. That is: If you’re looking at two distinct objects that are close together from Earth’s perspective, can you tell those two objects apart? In the great expanse of space, even objects that are very far apart from one another, like a sun and its planets, can be hard to resolve.
In fact, when seen from Earth with the naked eye, the two stars of the Alpha Centauri system are faint and often appear as one star in the sky. Any telescope could show you that these are indeed separate stars, but to make out orbiting planets, a far more challenging task, we need to have an image with much, much higher resolution.
So what’s the challenge here? For a ground-based telescope, it’s the turbulence in the Earth’s atmosphere. This is the same reason that stars twinkle. In space, stars appear as simple points of light; they’re so far away that even the biggest ones are nothing more than a point. But as their light passes through the Earth’s atmosphere, that light becomes distorted. By the time it gets to your eye — or to a telescope — it’s basically a twinkling blob. It’s impossible to make out an orbiting planet unless you correct for the degradation.
That’s where adaptive optics comes in. We use something called a deformable mirror. It’s a mirror that we bend to correct the turbulence. This allows us to see the image more or less as you would in space. Our goal in adaptive optics is to obtain the sharpest possible images, for the largest possible telescopes. Because of atmospheric turbulence, a 10-centimeter (4 inches) backyard telescope has the same resolution as the 10-meter (33 feet) Keck telescope in Hawaii (one of the world’s largest optical telescopes). But with adaptive optics, the larger, more powerful telescopes are much better at resolving distant objects.
So what about telescopes in space? There, the problem is subtler. You don’t have the issue of distortion from the atmosphere, and this means you can see objects more clearly. This is crucial if you’re trying to resolve a very faint, small, rocky planet in the habitable zone of a bright star, like the Alpha Centauri imaging initiative Project Blue is doing.
But when the prize is this small, even miniscule imperfections in the telescope mirror and lenses can degrade the image. As the telescope circles the Earth, it will be warmed by the sun and cooled again by the Earth’s shadow. This will cause the telescope’s parts to expand and contract ever so slightly — again, causing small changes to the optics that could prevent observers from making out the tiny faint glimmer of a planet.
I’m currently working with the Magellan Telescope in Chile, trying to determine if close stars like Alpha Centauri A and B have gas giants in close orbits. If a planet is close enough to the star — within the habitable zone, where liquid water could exist on the surface — such a gas giant would be fairly warm. We can see the heat from large, warm planets in infrared light.
But here’s the thing: Gas giants are so big that their gravity clears rocky planets out of the way, sort of like a giant cosmic leaf blower. This means that if there are gas giants orbiting close to Alpha Centauri A or B, they would have cleared any Earth-like planets out of the system eons ago.
For that reason, I’m hoping we come up empty. If we can show that there are no gas giants in the habitable zone, it means that another Earth could be lurking there instead.
Jared Males is an assistant astronomer at the University of Arizona’s Steward Observatory and a member of Project Blue’s Science and Technology Advisory Committee.
The untimely end of the consumer version of Google Glass in 2015 may have had some grieving the early death of augmented reality. But the technology is being resurrected by companies on the manufacturing floor.
Take for example Lockheed Martin. Technicians at the aerospace manufacturer use Microsoft’s Hololens headset to design and examine models of spacecraft such as the Mars lander ahead of it’s 2018 mission.
The technology is also very useful for training and production.
“At Lockheed Martin, we see the HoloLens being a tremendous benefit in terms of 3D, the speed and quality that we can do our work,” says Darin Bolthouse, an engineering manager at Lockheed Martin.
“The ability to pull together all information that the technician has to reference in building a satellite or a space craft and all the other products that we build here, the ability to have all that information available in the HoloLens, and the guided instructions to pull together a product is going to have a tremendous advantage,” he said.
Automakers like Volkswagen and BMW have also experimented with augmented reality. The technology proves useful in leaving workers’ hands free and making communication between teams easier.
The world’s largest aircraft maker, Boeing is also giving augmented reality a shot. The company has used the technology to help technicians navigate the thousands of wires needed to connect a plane’s electrical systems, or “wire harnesses,” as they are called.
The future or augmented reality is looking good. According to an IDC study, the augmented reality market was worth $209 million in 2016 but is expected to grow to $49 billion by 2021.
Mars may have harbored even more liquid water on its surface in the ancient past than scientists had thought, a new study suggests.
Mars meteorites commonly contain a mineral called merrillite, which is regarded as an indicator of dry environments. But some of the merrillite in Mars meteorites may actually have been converted from a “wet” mineral called whitlockite by the asteroid impacts that blasted the Red Planet rocks toward Earth, the study indicated.
“If even a part of merrillite had been whitlockite before, it changes the water budget of Mars dramatically,” study co-leader Oliver Tschauner, a professor in the Department of Geoscience at the University of Nevada, Las Vegas, said in a statement
Researchers are still trying to get a handle on that Martian “water budget.” Scientists know that the planet was once wet; for example, observations by NASA’s Curiosity rover have revealed that Mars hosted possibly habitable lake-and-stream systems for lengthy stretches billions of years ago.
But it’s unclear just how much liquid water there was on the planet, and how long it lasted. Some scientists think the Red Planet featured a giant ocean that covered much of the Martian surface, for instance, whereas others argue that the wet stuff occurred in more limited pockets.
The new study hints that ancient Marsmay have been very wet indeed. The research team created synthetic whitlockite in the lab. They smashed the stuff with metal plates blasted from a gas-pressurized gun at up to 1,680 mph (2,700 km/h) to simulate an asteroid strike, then used X-ray beams to study the composition of the “shocked” sample.
The researchers found that up to 36 percent of the synthetic whitlockite was converted to merrillite at the plate-sample interface. And the extreme pressures and temperatures generated during the experiment lasted just 100 billionths of a second, 1 percent to 10 percent as long as they would during real asteroid impacts. Such strikes may therefore have produced “almost full conversion” to merrillite, Tschauner said in the same statement.
Adding to the intrigue, the hydrogen-containing whitlockite is water-soluble and contains phosphorus, one of the key building blocks for life on Earth, the researchers said.
“Thus, significant whitlockite on Mars would mean more available phosphorus in aqueous environments for any potential prebiotic or biotic reactions,” the researchers wrote in the new study, which was published online Monday (March 6) in the journal Nature Communications.
“The only missing link now is to prove that [merrillite] had, in fact, really been Martian whitlockite before,” Tschauner added. “We have to go back to the real meteorites and see if there had been traces of water.”
Still, there’s only so much that can be learned from lab experiments and studies of Mars meteorites, study team members said. (These latter rocks have been considerably altered by their violent expulsion from Mars and time on Earth, after all.)
So the research team, like many other scientists, are keen for a sample-return mission that would bring a pristine piece of the Red Planet to Earth for study.
“It’s really important to get a rock that hasn’t been ‘kicked'” like Mars meteorites have, study co-author Martin Kunz, a staff scientist at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, said in the same statement.
Bizarre flashes of cosmic light may actually be generated by advanced alien civilizations, as a way to accelerate interstellar spacecraft to tremendous speeds, a new study suggests.
Astronomers have catalogued just 20 or so of these brief, superbright flashes, which are known as fast radio bursts (FRBs), since the first one was detected in 2007. FRBs seem to be coming from galaxies billions of light-years away, but what’s causing them remains a mystery.
“Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven’t identified a possible natural source with any confidence,” study co-author Avi Loeb, a theorist at the Harvard-Smithsonian Center for Astrophysics, said in a statement Thursday (March 9). “An artificial origin is worth contemplating and checking.” ]
One potential artificial origin, according to the new study, might be a gigantic radio transmitter built by intelligent aliens. So Loeb and lead author Manasvi Lingam, of Harvard University, investigated the feasibility of this possible explanation.
And the huge amounts of energy involved wouldn’t necessarily melt the structure, as long as it was water-cooled. So, Lingam and Loeb determined, such a gigantic transmitter is technologically feasible (though beyond humanity’s current capabilities).
Why would aliens build such a structure? The most plausible explanation, according to the study team, is to blast interstellar spacecraft to incredible speeds. These craft would be equipped with light sails, which harness the momentum imparted by photons, much as regular ships’ sails harness the wind. (Humanity has demonstrated light sails in space, and the technology is the backbone of Breakthrough Starshot, a project that aims to send tiny robotic probes to nearby star systems.)
Indeed, a transmitter capable of generating FRB-like signals could drive an interstellar spacecraft weighing 1 million tons or so, Lingam and Loeb calculated.
“That’s big enough to carry living passengers across interstellar or even intergalactic distances,” Lingam said in the same statement.
Humanity would catch only fleeting glimpses of the “leakage” from these powerful beams (which would be trained on the spacecraft’s sail at all times), because the light source would be moving constantly with respect to Earth, the researchers pointed out.
The duo took things a bit further. Assuming that ET is responsible for most FRBs, and taking into account the estimated number of potentially habitable planets in the Milky Way (about 10 billion), Lingam and Loeb calculated an upper limit for the number of advanced alien civilizations in a galaxy like our own: 10,000.
Lingam and Loeb acknowledge the speculative nature of the study. They aren’t claiming that FRBs are indeed caused byaliens; rather, they’re saying that this hypothesis is worthy of consideration.
“Science isn’t a matter of belief; it’s a matter of evidence,” Loeb said. “Deciding what’s likely ahead of time limits the possibilities. It’s worth putting ideas out there and letting the data be the judge.”
The new study has been accepted for publication in The Astrophysical Journal Letters. You can read it for free on the online preprint site arXiv.org.
Scientists, have at it: NASA has released raw data from the Kepler Space Telescope probing the many Earth-size planets around the star TRAPPIST-1.
In February, data from the Spitzer Space Telescope revealed that seven planets orbit the ultracool dwarf star, and now, the recently released Kepler data (and its final, processed version) will give a complementary look at the worlds, three of which might orbit in the star’s habitable zone.
Kepler’s observations could provide more detail about the gravitational interactions among the planets, and perhaps reveal even more planets around the star, NASA officials said in a statement
As part of its K2 mission, Kepler examined the TRAPPIST-1 system from Dec. 15, 2016, to March 4, 2017 — and its data became much more exciting upon the Feb. 22 announcement of additional Earth-size planets orbiting the star. Yesterday (March 8), Kepler researchers released the unprocessed data from that survey for astronomers to use in preparing research proposals.
“Scientists and enthusiasts around the world are invested in learning everything they can about these Earth-size worlds,” Geert Barentsen, K2 research scientist at NASA’s Ames Research Center in California, said in the NASA statement. “Providing the K2 raw data as quickly as possible was a priority to give investigators an early look so they could best define their follow-up research plans. We’re thrilled that this will also allow the public to witness the process of discovery.”
The release is timely because many proposals to study TRAPPIST-1 this winter with ground-based telescopes are due this month, the statement said.
On the Kepler website, Barentsen encouraged scientists to dig into the results and blog or tweet analysis, but advised everyone to wait until the final, processed results are released in late May to cite them in journal papers.
Barentsen also included a preliminary graph of the light curve, the way the star darkened as planets passed across it, which shows hints of at least six planets (as well as star spots) visible in the data.
When K2’s December-March observation plan was established, TRAPPIST-1’s planets were unknown, and the star system wasn’t on the list for investigation. But researchers found evidence of three planets around the star in May 2016, so the Kepler team adjusted the mission to include the newly exciting target.
“We were lucky that the K2 mission was able to observe TRAPPIST-1,” Michael Haas, science office director for the Kepler and K2 missions at Ames, said in the statement. “The observing field for Campaign 12 [the December-March campaign] was set when the discovery of the first planets orbiting TRAPPIST-1 was announced, and the science community had already submitted proposals for specific targets of interest in that field.
“The unexpected opportunity to further study the TRAPPIST-1 system was quickly recognized, and the agility of the K2 team and science community prevailed once again,” Haas added.
Kepler’s original and K2 missions have been responsible for more than 2,400 confirmed exoplanet discoveries. The space telescope uses extremely precise measurements of stars’ brightness over time to identify little dips in brightness that indicate planets in front of the star, called the transit method of exoplanet detection.
Although the transit method can identify only planets that are oriented to pass by the star from Earth’s point of view, it’s an extremely powerful technique. The Spitzer Space Telescope, which counted the seven planets around TRAPPIST-1, used a similar process measuring infrared light.
NASA’s upcoming James Webb Space Telescope, another infrared telescope, could give researchers an even more detailed view of the planets, and help scientists measure whether those potentially habitable ones have atmospheres friendly to life. The telescope will be powerful enough to analyze the light passing from the star through the planets’ atmospheres, letting researchers determine their composition.
Pluto’s “demotion” to a dwarf planet back in 2006 is still a touchy subject, even among scientists.
When you account for the fact that astronomers, who study stars and black holes, were the ones who decided on the definition of a planet that resulted in Pluto’s declassification, it’s understandable that various planetary scientists don’t even want to talk about it.
“It’s often like bringing up politics and religion in polite conversation,” said planetary geologist Kirby Runyon from Johns Hopkins University, in an email to Seeker. “Some planetary scientists can’t understand why some of us care so much. Generally, it’s not discussed over a beer at a conference.”
But Runyon does care. In fact, he’s so passionate about what constitutes a planet, that he is the lead author of a new paper that proposes a new geophysical-based definition. This revised description is centered on intrinsic physical properties such as surface features instead of the extrinsic orbital characteristics that the International Astronomical Union (IAU) used as the basis of much of their planetary definition when they formulated it nearly 11 years ago.
Runyon and his co-authors — including Alan Stern, the principal investigator of the New Horizons mission to Pluto — will present their paper at the 48th Lunar and Planetary Science Conference in March.
The new paper states the definition of a planet as “a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.”
In other words: Anything round in space that isn’t a star.
While this definition is refreshingly simple — particularly compared to confusing requirements about clearing orbital zones — Runyon and his co-authors say that this definition is “in keeping with both sound scientific classification and peoples’ intuition.”
But their proposed definition would increase the number of ‘planets’ in our solar system to over 110, including Earth’s Moon and about 18 other moons, a few asteroids, and numerous Kuiper Belt Objects.
How would students memorize all of those planets?
They wouldn’t, answer Runyon and his colleagues. Instead, they should focus on the organization system of the solar system.
“Understanding the natural organization of the Solar System is much more informative than rote memorization,” says the paper. “Teaching the zones of the Solar System from the Sun outward and the types of planets and small bodies in each is perhaps the best approach.”
There are many who feel that the revised planet definition adopted by the IAU is technically flawed, since it doesn’t address extrasolar planets or wandering ‘rogue’ planets — and, again, there’s the whole zone clearing requirement, which many experts say no planet in our solar system can satisfy.
When I spoke with Stern about this last year, he didn’t mince words.
“Astronomers aren’t experts in planetary science, and they basically passed a bunch of B.S. off on the public back in 2006 with a planet classification so flawed that it rules the Earth out as a planet, too,” he said. “A week later, hundreds of planetary scientists, more people than at the IAU vote, signed a petition that rejects the new definition. If you go to planetary science meetings and hear technical talks on Pluto, you will hear experts calling it a planet every day.”
“Planetary scientists call lots of round things planets, including Pluto and Titan,” he said. “If, in linguistics, definition is influenced by usage (especially by experts in the field), then by usage alone Pluto is a planet.”
Runyon also feels this new definition can and should be used without needing ratification by the IAU.
“We don’t need to give the IAU the authority to tell us what a planet is,” he remarked. “To be fair, the IAU serves a great purpose in astronomy and does great stuff, but they don’t need to tell planetary geologists what a planet is or isn’t.”
Runyon admitted that some planetary geologists are okay with the IAU definition, and others don’t really care. Some can’t understand why it’s a point of contention.
“For whatever reason, this is something that I care deeply about,” he said, “I think partly because I want the general public to support space exploration and how they view the solar system affects their interest level.”
That’s illustrated in the implicit assumption in the question Runyon said he gets often: Why did you send a spacecraft to Pluto if it’s not a planet anymore?
It’s as though “non-planets” cease to be interesting enough to warrant scientific exploration, the paper says, although this wasn’t the intention of the IAU.
Runyon said that he chose to submit this paper as a poster at the upcoming Lunar and Planetary Science Conference in the K-12 education section, because he wants teachers to teach this new definition, as he sees this as the most influential way to get the public to adopt it.
“Get ’em while they’re young!” he quipped.
The search for Martian life may take NASA’s next Red Planet rover to a site already explored by one of its smaller cousins.
Columbia Hills/Gusev Crater, which NASA’s now-dead Spirit rover studied intensively from 2004 through 2009, is one of three finalist landing sites for the agency’s next Mars rover, a life-hunting machine scheduled to launch in 2020.
Spirit found evidence of an ancient hydrothermal system, meaning Columbia Hills/Gusev once hosted liquid water and an energy source — two of the key ingredients necessary for life as we know it.
“Because NASA’s stated objective for the 2020 rover is to seek signs of past microbial life, the fact that we can point to possible signs of microbial life among rocks in the Columbia Hills is a major reason to go back,” said Steven Ruff, associate research professor at Arizona State University’s Mars Space Flight Facility in Tempe, Arizona.
NASA held a landing-site decision meeting in Monrovia, California, last month, from Feb. 8 through Feb. 10.
The meeting involved more than 250 scientists and spacecraft engineers, who took part in person or via the Internet. After the meeting ended, the participants spent several days debating options and voting. They finally settled on three potential landing sites for the 2020 rover. In addition to Columbia Hills/Gusev, the researchers selected:
Jezero Crater. A place that exhibits a dried-up lake and possibly a storehouse of past microbial For the most part, the 2020 rover will follow the landing playbook used by NASA’s Mars rover Curiosity, which touched down inside Gale Crater in August 2012 and is currently exploring the foothills of the 3.4-mile-high (5.5 kilometers) Mount Sharp.
The 2020 Mars rover will experience the same “7 minutes of terror” entry, descent and landing scenario, which ends with the use of a rocket-powered sky crane lowering the rover onto Mars terrain. [7 Minutes of Terror: Curiosity Rover’s Risky Mars Landing (Video)]
But the new rover features some updates that will make its landing special, said Allen Chen, entry, descent and landing lead for Mars 2020 at NASA’s Jet Propulsion Laboratory in Pasadena, California.
Two new techniques — Range Trigger and Terrain-Relative Navigation —make it feasible to shrink the rover’s landing ellipse considerably, compared to previous Mars landers, Chen said. Those new abilities allow the rover to “get close to the fun stuff” that scientists are hungry for, Chen told Space.com.
Terrain-Relative Navigation will allow the 2020 rover to avoid rough terrain, sharp slopes and other perils, while Chen said that Range Trigger permits precise timing of parachute release. Onboard software will autodecide if the rover’s parachute is to be deployed early or late, given how close the robot might be to its desired touchdown target, Chen said..
Mars 2020 and Curiosity also have different mission goals. Curiosity is tasked primarily with determining whether or not Gale Crater has ever been capable of supporting microbial life — a question the rover answered in the affirmative early in its mission. But Mars 2020 will actually hunt for signs of past life.
The 2020 rover will drill and cache the most compelling astrobiological samples at the selected site for later pickup and return to Earth. Once transported back to our home world, specimens would be subject to the best scientific scrutiny that researchers can muster, given a bevy of powerful and innovative lab tools.
Just when — and how — these samples will make it to Earth is unknown; at present, there is no programmatic/budgetary go-ahead on a pickup mission.
It’s possible that astronauts could be involved; after all, NASA is also working to get people to the vicinity of the Red Planet sometime in the 2030s.
“I’ve thought for a couple of years now that sending humans to pick up the sample cache in orbit around Mars would be a great way to advance exploration goals,” Ruff said.
“I have joked that it would be like Apollo 8 going for takeout,” he added, referring to the nonlanding human mission that orbited the moon in December 1968.
“We’d be exercising the hardware needed to get humans to Mars and back and completing a major scientific objective of returning Martian samples to Earth,” Ruff said. “But if the development timeline for such a mission is substantially longer than a robotic sample-return mission, I’d have a different opinion.”
“I am not very enthusiastic about Mars 2020,” said Chris McKay, a research scientist at NASA’s Ames Research Center in Moffett Field, California. “It will sure be fun to have another big rover on Mars, but I don’t think it will advance the science much over Curiosity.”
McKay underscored two things gleaned from Curiosity — items that seem to have been ignored, he said.
“First, to search for signs of life, we have to collect samples. 2020’s approach to do all the in situ science with instruments that don’t require a sample is a step backward,” McKay told Space.com.
“The second lesson from Curiosity is that we need to get these samples from deep,” McKay said. At old equatorial sites on Mars, “deep” means many meters, he said. In the polar sites — like the Phoenix lander site that was robotically explored in 2008 — 20 inches (51 centimeters) may be enough, McKay added.
McKay said the Mars 2020 rover will collect samples only from very shallow depths.
“I doubt there will be much interest in going back to Mars to pick up these samples,” he said. “But certainly the coring and caching will be interesting technology demonstrations.”
Mars getting busy
The 2020 rover isn’t the only craft being prepped for a trip to Mars in the near future.
NASA aims to launch a lander called InSight next year, to investigate the Red Planet’s interior structure. The life-hunting ExoMars rover, a joint effort of the European Space Agency and Russia’s space agency, is scheduled to lift off in 2021, and China plans to launch its own Mars rover in that same general time frame.
And then there’s SpaceX. Elon Musk’s company intends to launch its uncrewed Dragon capsule toward Mars in 2020, with follow-up missions occurring every two years or so thereafter. Crewed missions aboard the company’s Interplanetary Transport System could begin sometime in the 2020s as well.
Advocates of Pluto’s planethood are about to fire another salvo in the decade-long debate about the famous object’s status.
Scientists on NASA’s New Horizons mission, which performed the first-ever flyby of Pluto in July 2015, will officially propose a new definition of “planet” next month, at the 48th Lunar and Planetary Science Conference in The Woodlands, Texas.
The new definition would replace, or supersede, the one devised by the International Astronomical Union (IAU) in 2006. A planet, the IAU determined, is a body that orbits the sun without being the moon of another object; is large enough that its own gravity has rounded it into a sphere (but not so large that it undergoes fusion reactions, like a star); and has “cleared its neighborhood” of most other bodies.
Pluto failed to meet this last criterion, because its neighborhood — the vast Kuiper Belt beyond Neptune’s orbit — is full of small, icy objects. So Pluto was stripped of the planethood it had enjoyed since its 1930 discovery, and was reclassified as a dwarf planet.
Many scientists and laypeople alike cried foul at the time, and have continued to object to the definition and Pluto’s concomitant “demotion.” The New Horizons team members, including mission principal investigator Alan Stern, lay out their main arguments against the IAU definition in the paper they will present next month:
“First, it recognizes as planets only those objects orbiting our sun, not those orbiting other stars or orbiting freely in the galaxy as ‘rogue planets,'” the researchers, led by K.D. Runyon of Johns Hopkins University in Baltimore, wrote in the paper, which you can read here. “Second, it requires zone clearing, which no planet in our solar system can satisfy since new small bodies are constantly injected into planet-crossing orbits, like NEOs [near-Earth objects] near Earth. Finally, and most severely, by requiring zone clearing, the mathematics of the definition are distance-dependent, requiring progressively larger objects in each successive zone. For example, even an Earth-sized object in the Kuiper Belt would not clear its zone.”
As an alternative, the researchers will propose a “geophysical definition” — one based solely on an object’s intrinsic characteristics (and not on how it interacts with its environment). Here it is:
“A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.”
Or, more simply: “round objects in space that are smaller than stars.” (The tricky matter of brown dwarfs, “failed stars” that are larger than planets but smaller than true stars, is left up in the air, “so as to not force a premature definition on the larger end of planetary scales,” the researchers wrote.)
Pluto would regain its planethood under this new definition, and a lot of other bodies would be viewed as planets for the first time — including Earth’s moon (and any other moon large enough to be spherical, such as the Jovian satellite Europa). Indeed, the number of officially recognized planets would balloon from eight to about 110, the researchers wrote.
But that’s OK, they added; there’s no rule stating that schoolchildren must be able to memorize all the planets. And swelling the planet ranks would better convey the exciting diversity found throughout the solar system, the team members wrote.
“This definition highlights to the general public and policymakers the many fascinating worlds in our solar system that remain unexplored and are worthy of our exploration, along with the necessary budgets,” they wrote.
But not everyone is clamoring for Pluto to be reclassified. One person who’s quite happy with the status quo is Mike Brown, an astronomer at the California Institute of Technology in Pasadena. Brown and his team have discovered many objects in the outer solar system, showing that Pluto is far from the only large object in the Kuiper Belt.
This growing realization seems to have spurred the IAU to draft its 2006 definition; indeed, Brown chose “@plutokiller” for his Twitter handle.
So what does Brown think about the proposed new definition? You be the judge.
“Oh god the stupid Pluto stories are back. Yes, someone has proposed making Pluto a planet again. No, nothing is changed or new,” Brown tweeted Tuesday (Feb. 21). “Also, I should note, that proposal would make the moon a planet. Which is about 500 years out of date. But, ok #MakeTheMoonGreatAgain,” he added in another tweet.
The 48th Lunar and Planetary Science Conference runs from March 20 through March 24. It should be lively!
The discovery of seven Earth-size worlds circling a nearby star could be a watershed moment in humanity’s quest to find alien life, scientists say.
On Wednesday (Feb. 22), an international team of astronomers announced that seven planets about the size of our own orbit TRAPPIST-1, a tiny, cool star that lies just 39 light-years from Earth. Three of these planets orbit in the star’s “habitable zone,” where lakes, rivers and oceans could exist on a world’s surface, but all seven could potentially harbor surface water, given the right atmospheric conditions, discovery team members said.
“With this discovery, we’ve made a giant, accelerated leap forward in the search for habitable worlds, and life on other worlds, potentially speaking,” Sara Seager, a planetary scientist at the Massachusetts Institute of Technology, said during a news conference Wednesday.
The find is exciting for several reasons, according to Seager, who is not part of the discovery team. First of all, with multiple potentially water-bearing worlds, the TRAPPIST-1 system is a promising candidate to host life — even if researchers don’t have a completely accurate understanding of its habitable zone (also known as “Goldilocks zone”).
“You could say, colloquially, it’s like in this planetary system, Goldilocks has many sisters,” Seager said.
Furthermore, about 15 percent of the stars in the sun’s neighborhood are ultracool dwarfs like TRAPPIST-1, which is only slightly larger than Jupiter. Many of these nearby dwarfs may host rocky, potentially habitable planets, if TRAPPIST-1 is any guide.
“With this amazing system, we know there must be many more potentially life-bearing worlds out there, just waiting to be found,” Seager said.
Finding such worlds is just the beginning. TRAPPIST-1 is close enough to Earth that astronomers will soon be able to characterize the seven planets’ atmospheres in detail — a key step in gauging the worlds’ habitability — and probe them for oxygen, ozone, methane and other potential signs of life. Indeed, NASA’s $8.8 billion James Webb Space Telescope will likely start doing just that shortly after it launches in late 2018.
Baltimore. Lewis is not part of the TRAPPIST-1 discovery team, either, though she was co-leader of a group that used NASA’s Hubble Space Telescope to begin studying the atmospheres of two of the planets in the system. (Researchers first announced the detection of three planets around TRAPPIST-1 in 2016; the new discovery confirmed two of those previously spotted worlds, and bumped the total planet tally to seven.)
Three huge ground-based observatories scheduled to come online in the early to mid-2020s — the European Extremely Large Telescope, the Giant Magellan Telescope (both in Chile) and the Thirty Meter Telescope (in Hawaii) — should also be able to study the atmospheres of nearby planets such as the TRAPPIST-1 worlds, the builders of the telescopes have said.
There should be many planets for them to investigate. For example, the team behind the new TRAPPIST-1 discovery will soon begin hunting for planets orbiting 1,000 nearby ultracool dwarfs, in a project called SPECULOOS (Search for Habitable Planets Eclipsing Ultra-cool Stars). And in 2018, NASA plans to launch the TESS (Transiting Exoplanet Survey Satellite) mission, which agency officials have said will likely find thousands of worlds circling stars in the sun’s neck of the woods.
“TRAPPIST-1 is the most exciting one so far, but we hope to have many more of these, and lots of chances to find signs of life in the future,” Seager said.
Wouldn’t it be great if, when landing a robotic mission on another planet, the lander or rover could just scoop a sample, drop it into a chemical analyzer and get a “positive” or “negative” result for extraterrestrial life?
Well, this chemistry test isn’t so farfetched and scientists at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., are working on a method that is 10,000 times more sensitive than any other method currently employed by spacecraft.
Focused on the detection of specific types of amino acid tied to life, the researchers propose mixing a liquid sample collected from the surface of an alien world with a chemical known as a liquid reagent. Then, by shining a laser across the mixture, the molecules it contains can be observed moving at different speeds when exposed to an electric field. From this, the different molecules can be identified and the whole thing can be done autonomously, no humans required.
The method known as “capillary electrophoresis” can be used to detect many different types of amino acids simultaneously.
“Our method improves on previous attempts by increasing the number of amino acids that can be detected in a single run,” said researcher Jessica Creamer in a statement. “Additionally, it allows us to detect these amino acids at very low concentrations, even in highly salty samples, with a very simple ‘mix and analyze’ process.”
The team has already tested the method on water taken from Mono Lake in California — a mass of salty water with an extreme alkalinity — and simultaneously analyzed 17 different amino acids.
“Using our method, we are able to tell the difference between amino acids that come from non-living sources like meteorites versus amino acids that come from living organisms,” said Peter Willis, the project’s principal investigator also at JPL.
Molecules like amino acids come in two different “chiralties” that are mirror images of one another. Non-organic sources contain roughly equal “left-” and “right-handed” chirality amino acids, whereas amino acids from living organisms are predominantly left-handed — for life on Earth in any case. This differentiation can be detected by capillary electrophoresis.
This method is exceedingly powerful for several reasons. Currently, NASA is putting great efforts into looking for habitable environments on Mars. We know that the Red Planet used to be a very wet place and there’s evidence that suggests very briny sources of liquid water exists to this day. If life has ever taken hold on Mars, and if a future mission can directly sample this salty, toxic water, it’s sensitive chemical analyses such as this that will likely track it down.
Also, in the future, it is hoped that a mission may be sent to Jupiter’s moon Europa, which is known to possess an extensive subsurface ocean. Many components for life as we know it exists on Europa, so if a robotic mission can be sent to the moon’s ice-encrusted surface, or even dropped into the ocean itself, finding out whether there’s life elsewhere in the solar system could be one simple chemistry test away.
The Milky Way is littered with a vast diversity of planets: giants that blur the line between planet and failed-star brown dwarf; tiny worlds similar in size to Earth’s moon; planets that take 100,000 years to orbit their suns or whip around in hours; lava worlds; ice worlds; and planets that circle multiple suns or whirling pulsars.
Scientists find them by watching stars that wobble, change gravity, vary in color or dip slightly in brightness. (This last strategy is employed by the most prolific planet hunter of all time, NASA’s Kepler space telescope.) And someone needs to keep track of them all.
Rachel Akeson, deputy director at the NASA Exoplanet Science Institute, leads the space agency’s Exoplanet Archive, which is tasked with cataloging the ever-growing horde of planets known to exist outside the solar system.
“In 2011, there were about 700 [confirmed exoplanets]; now we’re over 3,400,” Akeson told Space.com. “In the next five years, there’s going to be tens of thousands.”
Those newly discovered exoplanets will come courtesy of various space observatories that are operating now or will come online soon. For example, the European Space Agency’s Gaia mission is precisely measuring the positions of 1 billion Milky Way stars, and the work should allow astronomers to notice movements caused by the pull of many orbiting planets.
And NASA’s Transiting Exoplanet Survey Satellite (TESS) is scheduled to launch to 2018 to search for planets all over the sky circling stars relatively close to the sun, using the same method as Kepler.
NASA’s Exoplanet Archive will house them all; the database, which was made publicly accessible in 2013, lets researchers and enthusiasts understand the distribution and properties of planets found thus far as they come in, as well as data about the stars they orbit and planet “candidates” that have yet to be confirmed. The archive also generates graphs from the latest information to show exoplanet trends.
Right now, a big part of the Exoplanet Archive takes the shape of a large interactive table of confirmed planets, which have been checked and double-checked by the authors to make sure they’re not flukes in the data. Most of the planets aren’t directly imaged but rather detected via their effects on their parent stars, and confirmations can come from observation by various methods or by a strong pattern of “transits” across their stars.
The archive also hosts data about the stars’ light curves when they’re available, showing their brightening and dimming, as well as Kepler data that has not been confirmed as a planet’s signature. It keeps a list of false positives, too, and the list is always in flux; additions and changes in status are implemented continuously.
“Things can go in and then come back out,” Akeson said. “And I think in one case, something went in, came out and has gone back in. There’s this series of papers in the literature — basically two groups arguing with each other via the papers — whether or not this is the planet signature versus another kind of signature.”
An exoplanet’s data is officially added only once it appears in a peer-reviewed publication.
As more and more planets come in, researchers can use the archive to begin to understand the galaxy’s overall distribution of planets. Different methods of detection find different kinds of planets. For instance, transit measurements from Kepler or TESS are more likely to find planets that orbit close to their stars, and Gaia should generally find planets that orbit farther away, Akeson said. With current technology, systems like Earth’s would still be hard to find, and so researchers don’t know how common they are.
“We have no system that looks like the solar system yet, where you have these small, rocky planets on the inside and then several gas giants on the outside,” Akeson said. “We’re now getting to the point where we’re starting to see things that are true Jupiter analogues, but the Earth analogues are very hard to find still.”
Going forward, a thorough survey could help researchers understand how planetary systems evolve and why our solar system is the way it is, instead of featuring mini-Neptune and super-Earth planets like researchers have found in other star systems.
As scientists continue to discover exoplanets, the catalogue will keep growing. The archive’s researchers are talking to groups of users to determine the most helpful way to display the information, and planning the best ways to wrangle and verify the new waves of planets, Akeson said.
“We are going to have to keep up,” she said.
One of the closest rocky planets to Earth could have a wild climate that oscillates quickly between hot and cool periods, a new study reports.
This planet, known as Wolf 1061c, resides in the “habitable zone” of its host star, that just-right range of distances where liquid water could theoretically exist on a world’s surface. But it’s far from clear if Wolf 1061c could actually support life as we know it, study team members said.
For starters, Wolf 1061c — which circles a star located just 14 light-years from Earth’s sun — lies at the inner edge of the habitable zone, similar to where Venus is in Earth’s solar system. Venus has a hellish environment today, with surface temperatures reaching nearly 900 degrees Fahrenheit (480 degrees Celsius). [Gallery: The Strangest Alien Planets]
Venus likely had oceans on its surface in the past, but was so close to the sun that the heat made all the oceans evaporate. The water vapor assisted in trapping heat, contributing to Venus’ runaway greenhouse effect.
Something similar may have happened on Wolf 1061c, said the new study’s lead author, Stephen Kane, of San Francisco State University.
Wolf 1061c is “close enough to the star where it’s looking suspiciously like a runaway greenhouse,” Kane said in a statement.
Kane and colleagues studied Wolf 1061c’s parent star in detail using the Center for High Angular Resolution Astronomy array, which is located at the Mount Wilson Observatory in California. The researchers’ detailed measurements allowed them to better characterize the star’s habitable zone and the conditions that planets in the system likely experience. (Wolf 1061c is one of three worlds known to circle the star; all are “super-Earths,” planets slightly larger than Earth.)
“The Wolf 1061 system is important because it is so close [to Earth], and that gives other opportunities to do follow-up studies to see if it does indeed have life,” Kane said.
The team found that Wolf 1061c’s orbit varies at a faster rate than that of Earth, and this likely leads to greater climatic variations than Earth experiences
“It could cause the frequency of the planet freezing over or heating up to be quite severe,” Kane said.
So it’s unknown whether or not Wolf 1061c actually is habitable, study team members said. Getting to the bottom of this question may require more-advanced telescopes than are currently in operation, the researchers added.
One future instrument that should help is NASA’s $8.8 billion James Webb Space Telescope, which is scheduled to launch in late 2018 and succeed the Hubble Space Telescope, Kane said. Webb is expected to reveal the composition of nearby exoplanet atmospheres in detail.
Findings from the new study will appear in the next issue of the Astrophysical Journal. A preprint version is available now on the website arXiv.
Nearly two years after its historic encounter with the dwarf planet Pluto, NASA’s New Horizons spacecraft is getting ready for its next big adventure in the icy outskirts of the solar system.
Now, the spacecraft is on its way to a small, ancient object located about 1 billion miles (1.6 billion kilometers) beyond Pluto in the Kuiper Belt. This distant region surrounds the solar system and is filled with trillions of icy rocks that have yet to be explored. The new target was discovered by the Hubble Space Telescope in June 2014, and it was dubbed 2014 MU69.
Pluto, which officially lost its planetary status shortly after New Horizons launched in 2006, is also a Kuiper Belt object (KBO), and the largest of its kind. New Horizons became the first spacecraft to visit the Pluto system when the probe flew by the dwarf planet and its moons on July 14, 2015. [
It took the spacecraft about 16 months to beam back all of its data from the Pluto flyby, and planetary scientists have had a ball with that data.
The New Horizons flyby of the Pluto system was completely successful, and now we’ve got all the data on the ground and we’re putting a bow around it,” Alan Stern, the New Horizons principal investigator at Southwest Research Institute, said in a Facebook Live event on Thursday (Jan. 19).
Thanks to New Horizons, scientists now have a global map of Pluto and the most detailed images yet of the dwarf planet’s bizarre, mountainous landscape and icy volcanoes. Tall mountain ranges seen on Pluto also suggest recent geological activity on the dwarf planet’s surface.
New Horizons additionally beamed back a gorgeous photo of a huge, heart-shaped basin (unofficially called “Tombaugh Regio”) that quickly became Pluto’s most famous feature, taking the internet by storm and gracing the front page of hundreds of newspapers worldwide. The New Horizons science team has said Pluto’s “heart” seems to indicate the presence of a subsurface ocean.
The Pluto flyby also provided an opportunity to study Pluto’s moons, particularly Charon. Researchers discovered that Charon and Pluto are both tidally locked, meaning the same side of the moon always faces the dwarf planet and vice-versa. As a result, Pluto’s heart is always facing Charon. A giant red spot discovered on Charon’s surface revealed that the moon is taking some of its atmosphere from Pluto.
“One thing that we discovered is that small planets can be just as complex as big planets, and that really blew away our expectations,” Stern said, adding that all the new findings from Pluto “wet our appetite for future exploration of the Kuiper Belt.”
While the team continues to analyze the plethora of data — something that could go on for decades — it’s also busy planning for the next big stage of the mission, the flyby of 2014 MU69. That will occur in January 2019.
Pluto is the largest object known to exist in the Kuiper Belt, but MU69 is much smaller and more representative of the trillions of other KBOs, Kelsi Singer of the New Horizons science team told Space.com. Pluto is comparable to the size of North America at 1,475 miles (2,370 km) in diameter, while MU69 is less than 30 miles (about 45 km) across.
But MU69 isn’t just any old KBO. Singer said that the object “has a special kind of orbit that makes it possibly a type of object that is primordial and left over from early solar system formation. So we think that we’ll be able to look at what the building blocks of the solar system were like by going to this special object that has a special orbit.”
Part of the rationale for choosing MU69 as the next target was that it had a good location given the amount of fuel left on the New Horizons spacecraft.
“MU69 turned out to be really interesting, but we also had limited options,” Singer said. Using the Hubble Space Telescope, “we were searching the area of space where we had enough fuel left in the spacecraft to get to any objects that were there,” she said. Three good potential targets were located, but the other two “were just on the edge of where [the spacecraft] had enough fuel to get to.”
New Horizons runs on a radioactive plutonium power supply that could keep the spacecraft going through the mid-2030s, Glen Fountain, the New Horizons encounter project manager at Johns Hopkins University’s Applied Physics Laboratory, said during the Facebook Live event.
But after the 2019 flyby of MU69, the spacecraft probably won’t have much fuel left for special maneuvers, Singer said. “We won’t be able to switch directions, but we’ll still keep going out. It’s possible that we’ll be able to observe some other objects, but we haven’t identified any of them yet. So we’re going to keep an eye out to see what we can find.”
For now, the team will remain focused on planning the MU69 flyby and sifting through data from Pluto. The researchers need to plan the spacecraft’s every move far ahead of time; because of a 6-hour delay in communications with the distant spacecraft, they won’t be able to tell the probe what to do in real time. Instead, the team must program New Horizons at least several months in advance to do every observation and data transmission.
The spacecraft will take photos of MU69 along the way, starting out with pictures of a single-pixel speck from afar, Singer said. During the flyby, New Horizons will be able to get even closer to MU69 than it did with Pluto, because the small object has much less gravity. This means that the photos of MU69 will have a higher resolution than the photos of Pluto. Singer said that’s something she and the team look forward to seeing.
In April, New Horizons will be halfway to MU69 from Pluto, with 21 months of spaceflight left to go.
Microbes that rank among the simplest and most ancient organisms on Earth could survive the extremely thin air of Mars, a new study finds.
The Martian surface is presently cold and dry, but there is plenty of evidence suggesting that rivers, lakes and seas covered the Red Planet billions of years ago. Since there is life virtually wherever there is liquid water on Earth, scientists have suggested that life might have evolved on Mars when it was wet, and life could be there even now.
“In all the environments we find here on Earth, there is some sort of microorganism in almost all of them,” said Rebecca Mickol, an astrobiologist at the Arkansas Center for Space and Planetary Sciences at the University of Arkansas in Fayetteville, and the lead author of the study. “It’s hard to believe there aren’t other organisms out there on other planets or moons as well.”
Mickol and her team detailed their findings in the paper “Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars,” which was published in the journal Origins of Life and Evolution of Biospheres.
Previous research detected methane, the simplest organic molecule, in the Martian atmosphere. While there are abiotic ways to produce methane — such as volcanic activity — much of this colorless, odorless, flammable gas in Earth’s atmosphere is produced by life, such as cattle digesting food.
“One of the exciting moments for me was the detection of methane in the Martian atmosphere,” Mickol said. “On Earth, most methane is produced biologically by past or present organisms. The same could possibly be true for Mars. Of course, there are a lot of possible alternatives to the methane on Mars and it is still considered controversial. But that just adds to the excitement.”
On Earth, microbes known as methanogens produce methane, also known as natural gas. Methanogens typically live in swamps and marshes, but can also be found in the guts of cattle, termites and other herbivores, as well as in dead and decaying organic matter.
Methanogens are among the simplest and most ancient organisms on Earth. These microorganisms are anaerobes, meaning they do not require oxygen. Instead, they often rely on hydrogen for energy, and carbon dioxide is the main source of carbon atoms they use in creating organic molecules.
Methanogens contained in these test tubes, which also contained growth nutrients, sand and water, survived when subjected to Martian freeze-thaw cycles.
The fact that methanogens neither require oxygen nor photosynthesis means they could live just beneath the Martian surface, shielded from harsh levels of ultraviolet radiation on the Red Planet. This could make them ideal candidates for life on Mars.
However, the area just below the surface of Mars is exposed to extremely low atmospheric pressures, normally considered inhospitable to life. The surface pressure on Mars on average ranges from one-hundredth to one-thousandth that of the surface pressure of Earth over the course of the Martian year, too low for liquid water to last on the surface. In such thin air, water easily boils. (In contrast, the pressure at the highest point on Earth’s surface, the top of Mount Everest, is about one-third that of Earth’s surface pressure at sea level.)
To see if methanogens might survive such extremely thin air, Mickol and Timothy Kral, the senior author of the study and an astrobiologist at the University of Arkansas at Fayetteville, experimented with four species of methanogens. They included: Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, and Methanococcus maripaludis. Previous experiments on these four species over the course of more than 20 years generated a lot of data on these organisms and their rates of survival in simulated Martian conditions.
The more recent set of experiments, which took about a year, involved growing the microbes in test tubes within liquids as a proxy for the fluids potentially flowing through underground Martian aquifers. The microbes were fed hydrogen gas, and the liquids were covered with cotton swabs, which in turn were covered with dirt simulating what might be found on the Martian surface. The insides of each test tube were then subjected to low pressures.
Oxygen kills these methanogens, and maintaining a low-pressure, oxygen-free environment “was a difficult task,” Mickol said. Moreover, water evaporates quickly at low pressure, which can limit how long the experiments can last and can also clog the vacuum system with water.
Despite these problems, the researchers found that these methanogens all survived exposure of lengths varying from 3 to 21 days at pressures down to roughly six-thousandths of Earth’s surface pressure. “These experiments show that for some species, low pressure may not really have any effect on the survival of the organism,” Mickol said.
The scientists are also measuring methane to see whether methanogens are actively growing at low pressure and producing methane.
“The next step is to also include temperature,” Mickol said. “Mars is very, very cold, often getting down to -100ºC (-212ºF) at night, and sometimes, on the warmest day of the year, at noon, the temperature can rise above freezing. We’d run our experiments just above freezing, but the cold temperature would limit evaporation of the liquid media and it would create a more Mars-like environment.”
Mickol stressed that these experiments do not prove life exists on other planets. “That being said, with the abundance of life on Earth, in all the different extremes of environments found here, it’s quite possible there exists life — bacteria or tiny microorganisms — somewhere else in the Universe,” she said. “We’re just trying to explore that idea.”
This research was supported by the Exobiology & Evolutionary Biology element of the NASA Astrobiology Program.
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