With the help of X-ray videos, scientists have developed a new robot that mimics the way salamanders walk and swim.

The amphibious machine could shed light on the evolutionary leap that vertebrates made from the water to the land, the researchers said. The salamander-inspired robot could also one day be used for search-and-rescue missions or inspection operations, the scientists added.

In general, scientists investigate animal locomotion for insights that could, among other things, help people recover from devastating losses of mobility, said study senior author Auke Ijspeert, a bioroboticist at the Swiss Federal Institute of Technology in Lausanne. [The 6 Strangest Robots Ever Created]

Increasingly, scientists are creating robot copies of animals to perform such investigations of animal locomotion. One of the benefits of using robots is that the machines' actions are relatively easy to repeat, Ijspeert and his colleagues said. In addition, researchers can tinker with robot shapes in a methodical way, and the bots can perform movements that are unnatural or dangerous for animals, the scientists added.

The researchers focused on salamanders to shed light on the evolution of animal locomotion. "Salamanders have a body structure that is very close to the fossils of the first terrestrial vertebrates — that is, the first animals that switched from swimming to walking," Ijspeert told Live Science.

To create robo-salamanders, the researchers began by studyingPleurodeles waltl, a salamander about 7 inches (18 centimeters) long that moves both on land and in the water. The scientists took X-ray videos of two P. waltl specimens from the top and sides, tracking up to 64 points along the skeletons of the salamanders as they performed a variety of motions, such as walking on the ground, crawling underwater and even swimming.

The scientists then used a 3D printer to manufacture the skeleton of the robot. Onto this machine, they added 27 motors and a waterproof dry suit that was tailor-made to keep the robots' electronics from getting wet.

The so-called Pleurobot has fewer bones and joints than real-life salamanders. For instance, whereas the real amphibian has 40 vertebrae, the robot has only 11 segments along its spine mimicking vertebrae. [Super-Intelligent Machines: 7 Robotic Futures]

Still, the researchers said Pleurobot could imitate many salamander movements, especially at the limbs. This is because during the design of Pleurobot, the research team's computer models identified the minimum number of motorized segments needed to copy salamander motions, as well as the optimal placement of these parts along the robot's body.

The researchers have built salamander robots before. However, "what excites me most about Pleurobot is that for the first time we can test behaviors with a physical body that has the ability to move like the real animal, as never before," Ijspeert said.

"The robot can serve as a scientific tool to investigate how a newer mode of locomotion, walking with limbs, can be added to an older mode of locomotion, swimming," Ijspeert said. "Like the real salamander, the robot is able to perform both modes of locomotion. Both involve body undulations, but with different properties. During swimming, the undulations travel along the body like in lampreys and eels, with limbs folded backwards, while during walking, they stay in place and are well-coordinated with the limb movements in order to optimize forward speed."

In addition to providing insights on the evolution of animal locomotion, Pleurobot may also show how robots can move well in disorderly environments, Ijspeert said. "With improved control and sturdier mechanics, I hope to see Pleurobot helping in search-and-rescue scenarios in the near future," he said.

The scientists detailed their findings online June 29 in the journal Interface.

Original article on Live Science.

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The moons of Mars, Phobos and Deimos, may be the only survivors of a giant impact that created many short-lived, but now-absent moons around the Red Planet, a new study finds.

Phobos and Deimos are both small for moons — about 14 and 7.7 miles (22.5 and 12.4 kilometers) wide, respectively — and sort of potato-shaped. Compared to other satellites in the solar system, they look more like asteroids. As a result, astronomers previously hypothesized that these moons were asteroids captured by Mars' gravitational pull.

But if that were the case, previous research suggested that Phobos and Deimos would have relatively irregular orbits. In reality, these moons have nearly circular orbits positioned near the Martian equator. [Photos of Mars' Moon Phobos Up Close]

Another possible origin story for the Martian moons is that they coalesced from the debris of a giant impact, similar to the one largely thought to have formed Earth's moon. This rubble would have first formed a ring around Mars, and as moons emerged from this ring, they would have ended up with similarly circular orbits. However, this possibility raises the question of why Mars would end up with two moons instead of a single moon like Earth did, according to the new research paper.

To learn more about the potential origins of Phobos and Deimos,study lead author Pascal Rosenblatt, lead author on the new study, and a planetary scientist at the Royal Observatory of Belgium in Brussels, and his colleagues investigated scenarios "left on the side until now," Rosenblatt told Space.com. "I rapidly discovered they were left not always for justified reasons."

The scientists focused on the huge impact that previous research suggested created the gigantic Borealis basin in the northern lowlands of Mars, which covers two-fifths of the Red Planet's surface. Prior work suggested that this basin is an impact crater, created when an impactor about 1,200 miles (2,000 kilometers) wide struck Mars, generating a ring of debris around the Red Planet with a mass of about 110 quadrillion tons (100 quadrillion metric tons), or about 10,000 times the combined mass of Phobos and Deimos.

The research team's computer models suggested that, over time, in the inner part of this debris ring where the rubble was most densely packed, large moons up to hundreds of miles in diameter would have clumped or accreted together. In contrast, in the outer part of the debris ring, dust and rocks were thinly dispersed, making it difficult for this material to accrete into moons.

However, the scientists found that gravitational tugs from one or more large moons from the inner debris ring could have stirred up rubble in the outer ring, shepherding rock and dust to form smaller outer moons, such as Phobos and Deimos. The researchers calculated that after about 5 million years, Mars' gravitational pull would have doomed the other moons, sending them crashing to the Red Planet's surface and leaving Phobos and Deimos as the sole survivors.

"Our results pave a new path to re-understand the Martian system in a context of formation similar but not identical to [that of] our own moon," Rosenblatt told Space.com.

If a giant impact did create the Martian moons and the Borealis basin, that might help explain many other aspects of early Martian history, such as how Mars got its current rate of spin and lost its atmosphere and surface water, Rosenblatt said.

Although the orbit of Deimos is stable, previous research found that Phobos will one day crash against Mars as well. Indeed, a 2015 study found that Phobos already has stretch marks from the Red Planet's gravitational pull.

This model suggests that Phobos and Deimos are composed of a mix of material from Mars and the impactor that created the Borealis basin. Future research can test this model by returning samples from Phobos or Deimos to Earth for study, Rosenblatt said. He noted that Japan's space agency, JAXA, and the European Space Agency (ESA) are considering missions to these moons that "could be launched as soon as 2022 or 2024."

The scientists detailed their findings online July 4 in the journal Nature Geoscience.

Follow Charles Q. Choi on Twitter @cqchoi. Follow us @Spacedotcom,Facebookand Google+.

The Hubble Space Telescope has captured a stunning view of a fireworks display blazing up in deep space.

The celestial show comes courtesy of the dwarf galaxy Kiso 5639, which lies 82 million light-years from Earth in the constellation Ursa Major and hosts a frenzy of star birth.

"The dwarf galaxy is shaped like a flattened pancake, but because it is tilted edge-on, it resembles a skyrocket, with a brilliant blazing head and a long, star-studded tail," officials with the Space Telescope Science Institute in Baltimore, which operates Hubble's science program, wrote in a statement.

The majority of Kiso 5639's star-forming action is taking place in the galaxy's head, which is about 2,700 light-years wide. This ramped-up star birth has apparently been triggered by the accretion of gas in this region from surrounding space, researchers said.

The dwarf galaxy's head also features a number of large "holes," which are cavities in the gas blasted out by powerful supernova explosions.

Elongated galaxies such as Kiso 5639 are known as "tadpoles." There were much more abundant in the universe's early days than they are today, scientists said.

Hubble : Do You Know the Famous Space Telescope?

Hubble has revolutionized astronomers' understanding of the universe since its April 1990 launch.

"I think Kiso 5639 is a beautiful, up-close example of what must have been common long ago," Debra Elmegreen, of Vassar College in New York, said inthe same statement. "The current thinking is that galaxies in the early universe grow from accreting gas from the surrounding neighborhood. It's a stage that galaxies, including our Milky Way, must go through as they are growing up."

Elmegreen is lead author of a new study that's based on observations of Kiso 5639 Hubble made with its Wide Field Camera 3 instrument. The paper has been accepted for publication in The Astrophysical Journal.

The new photo, which was released on June 28, combines Hubble images taken in February 2015 and July 2015.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us@Spacedotcom, Facebook or Google+. Originally published on Space.com.

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Paul Sutter is an astrophysicist at The Ohio State University and the chief scientist at COSI Science Center. Sutter is also host of the podcasts Ask a Spaceman and RealSpace, and the YouTube series Space In Your Face. 

How can the universe expand faster than light travels?

It seems like it should be illegal, doesn’t it? Over and over (and over and over) we're told the supreme iron law of the universe: Nothing — absolutely nothing— can go faster than the speed of light. Done. Nothing further needs to be said about the issue.

And then come the astronomers, always excited by the chance to mess up your comfort zone. They come barging in with a simple observation: Some galaxies are moving away from us…wait for it…faster than the speed of light. What gives?

The big picture

First off, it's important to note that we live in an expanding universe. Every day the galaxies get farther apart from each other — on average. There are slight motions on top of that general expansion, leading to instances such as the Andromeda Galaxy heading on a collision course for the Milky Way. But in general, in the biggest of pictures, the galaxies are getting farther away from each other.

A key feature of this expansion is how uniform it is. Imagine a bunch of folks standing around the edges of a stretchy piece of fabric, tugging at it. Let us assume they're choreographed well and are able to walk backward and pull at the same rate. You, standing in the middle, would correctly observe that your "universe" is expanding: any objects placed on that fabric would slowly move away from you.

Because stretchy stuff is stretchy, the objects on the fabric close to you would appear to move away with some speed, but the farther objects would appear to move faster. Even though the folks doing the pulling are moving at a constant speed, the apparent stretch changes with distance. I swear this is true; you can even try it for yourself at home!

Now, let's jump to the universe. It's as if a bunch of folks are at the edge of the cosmos, gently tugging at the fabric of space-time, stretching it. Edwin Hubble was the first to measure the expansion rate. The number he got was way wrong, so I won't bother mentioning it, but good on him for trying. The more modern value is 68 kilometers per second per megaparsec, plus or minus a couple, but close enough.

I know, I know. You were probably following along just fine until that odd "per megaparsec" popped up. It's a distance: One megaparsec is 1 million parsec, which is 3.26 million light-years.

It means that if you look at a galaxy 1 megaparsec away, it will appear to be receding away from us at 68 km/s. If you look at a galaxy 2 megaparsec away, it recedes at 136 km/s. Three megaparsec away? You got it! 204 km/s. And on and on: for every megaparsec, you can add 68 km/s to the velocity of the far-away galaxy.

Over the limit

So it's easy enough to compute: At some point, at some obscene distance, the speed tips over the scales and exceeds the speed of light, all from the natural, regular expansion of space.

Yes, the movement of that galaxy can be interpreted as a "speed": you can measure the distance to it, wait awhile (to be fair, a really, really long while), and measure it again. Distance moved divided by time equals speed, and I guarantee you that the speed you measure can be faster than light.

No, this isn't a problem. [Watch as I explain in this video.]

The notion of the absolute speed limit comes from special relativity, but who ever said that special relativity should apply to things on the other side of the universe? That's the domain of a more general theory. A theory like…general relativity.

It's true that in special relativity, nothing can move faster than light. But special relativity is a local law of physics. Or in other words, it's a law of local physics. That means that you will never, ever watch a rocket ship blast by your face faster than the speed of light. Local motion, local laws. 

But a galaxy on the far side of the universe? That's the domain of general relativity, and general relativity says: who cares! That galaxy can have any speed it wants, as long as it stays way far away, and not up next to your face.

It goes deeper than this. Concepts like a well-defined "velocity" make sense only in local regions of space. You can only measure something's velocity and actually call it a "velocity" when it's nearby and when the rules of special relativity apply. Stuff super-duper far away, like the galaxies we're talking about it? If it's not close, it doesn't count as a “velocity” in the way that special relativity cares about.

Special relativity doesn't care about the speed — superluminal or otherwise — of a distant galaxy. And neither should you. 

Learn more by listening to the episode "How can the universe expand faster than light?" on the Ask A Spaceman podcast, available on iTunes and on the web at http://www.askaspaceman.com. Thanks to Mihail Etropolski, Nicolas Gregori, chris, and @archerelliott for the question that inspired this piece. Ask your own question on Twitter using #AskASpaceman or by following Paul@PaulMattSutter and facebook.com/PaulMattSutter.

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NASA's New Horizons Pluto probe isn't done exploring the far outer solar system just yet.

NASA has approved a mission extension for New Horizons, which performed the first-ever flyby of Pluto in July 2015. The spacecraft is now set for a Jan. 1, 2019 flyby of a small object called 2014 MU69, which lies about 1 billion miles (1.6 billion kilometers) beyond Pluto in the dark and frigid Kuiper Belt.

"The New Horizons mission to Pluto exceeded our expectations, and even today the data from the spacecraft continue to surprise," Jim Green, NASA’s Director of Planetary Science, said in a statement Friday (July 1). "We’re excited to continue onward into the dark depths of the outer solar system to a science target that wasn’t even discovered when the spacecraft launched." [Destination Pluto: NASA's New Horizons Mission in Pictures]

Though 2014 MU69 and Pluto occupy roughly the same realm of space, they are very different objects. For example, Pluto is 1,474 miles (2,372 km) wide, whereas 2014 MU69 is thought to be just 13 to 25 miles (21 to 40 km) across.

"This places [2014 MU69] in a key intermediate size regime to better understand planetary accretion," New Horizons principal investigator Alan Stern wrote in a blog post in April, when the New Horizons team officially submitted the mission extension proposal. "And given its 4-plus-billion-year existence in cold storage so far from the sun, MU69 will be the most pristine object ever visited by any space mission."

New Horizons should come within 1,900 miles (3,000 km) of 2014 MU69 during the 2019 flyby, Stern wrote — about four times closer than the probe got to Pluto during last year's historic encounter.

"If I do say so myself, the flyby of MU69 would be a landmark event, shattering all distance records for deep-space exploration, and yielding an impressive scientific bounty," added Stern, who's based at the Southwest Research Institute in Boulder, Colorado.

While New Horizons will keep zooming outward, NASA's Dawn spacecraft will stay put at the dwarf planet Ceres, the largest object in the asteroid belt, agency officials announced today.

Dawn's primary science mission just ended, and team members hadproposed sending the probe on to study an asteroid in the belt called Adeona. But NASA nixed that idea.

“The long-term monitoring of Ceres, particularly as it gets closer to perihelion — the part of its orbit with the shortest distance to the sun — has the potential to provide more significant science discoveries than a flyby of Adeona," Greensaid in the same statement.

A visit to Adeona would have marked the third cosmic body studied up-close by Dawn, which also orbited the protoplanet Vesta from July 2011 through September 2012. The spacecraft has enough fuel left to keep operating at Ceres through early 2017, mission team members have said.

NASA has also approved mission extensions though fiscal year 2018 for the Mars Reconnaissance Orbiter; Mars Odyssey Orbiter; MAVEN (Mars Atmosphere and Volatile EvolutioN) orbiter; the Opportunity and Curiosity Mars rovers; and the Lunar Reconnaissance Orbiter, agency officials announced Friday. NASA has also greenlit further support for the European Space Agency’s Mars Express orbiter mission.

These decisions were based on a report by the 2016 Planetary Mission Senior Review Panel, NASA officials said. The extensions are all contingent on the availability of resources, which will be determined by budget processes.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us@Spacedotcom, Facebook or Google+. Originally published on Space.com.

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