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Meet Five Microbes That Hitched a Ride on the Mars Rover

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Before any nation launches a spacecraft, the U.N.’s Outer Space Treaty requires the craft to undergo extensive cleaning, to “avoid harmful contamination of space and celestial bodies.” Basically, we don’t want our gross Earthly microbes to invade new regions of space and kill off other life that might potentially be living there. That’s especially true for Mars, because scientists think there’s a chance that single-celled organisms may have evolved there in the past, and might even still live on the Red Planet today.

NASA spacecraft get disinfected about 10 to 30 times before they launch, says Stephanie Smith-Rohde from the University of Idaho. But those decontamination sessions can’t catch everything. Smith-Rohde and her colleagues analyzed swabs that were taken from the surface of the Curiosity rover after cleaning and prior to launch. Their preliminary results, which were presented at a meeting of the American Society for Microbiology, turned up 377 organisms from 65 bacterial species.

Smith-Rohde’s team attacked these microbes with a battery of tests meant to simulate the harsh conditions of space and Mars, and they found that many of the microbes survived just fine—even, surprisingly, the bacteria that don’t form protective spores.

Scientists need to do longer-term studies, but so far the evidence suggests that some of these bacteria may have been capable of surviving a journey to Mars.

“Have we contaminated Mars already, or is there no way those microbes could survive the journey?” asks Smith-Rhode. “We don’t have answers to those questions yet. These studies allowed us to narrow down the organisms that we want to focus on.”

If Earth microbes did make it to Mars, here are the ones that are most likely to make themselves at home.

1. Staphylococcus

These bacteria (top), typically found in soil and on human skin, persevered in petri dishes that contained 20 percent salt. That’s really salty—by comparison, the ocean is only about 3 percent salt. It may be that Staphylococcus could also thrive in Mars’ salty sands and waters.

2. Enhydrobacter

During laboratory tests, Enhydrobacter colonies withstood a 2000-joule zap of radiation, “which is a pretty decent dose of UVC radiation,” says Smith-Rohde. They also endured a two-week desiccation experiment, wherein they had absolutely no access to water, with no major problems.

3. Moraxella

Nearly 50 percent of Moraxella bacteria outlived a one-hour dunk in a 5 percent hydrogen peroxide solution—a common cleaning agent meant to kill microbes on spacecraft.

4. Streptomyces

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Normally noted for their role in decaying organic matter, Streptomyces microbes are surprisingly hardy. In experiments, they were able to grow in the 20 percent salt solution as well as the two-week desiccation period, withstood low temperatures, and tolerated a pH of 9—similar in acidity to the soils of Mars.

5. Gracilibacillus


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Gracilibacillus one of a handful of types of bacteria that can eat the perchlorates found in Martian soil. “Gracilibacillus would definitely be a top contender to survive on Mars,” says Smith-Rohde.

Up next, Smith-Rohde and her colleagues plan to learn more about each of these microbes. They will expose the hardiest species to multiple extreme conditions at once, which is more like what they’d really experience in space, and also may determine whether they could endure the nine-month journey to Mars.

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Space
More Details Emerge About 'Oumuamua, Earth's First-Recorded Interstellar Visitor
 NASA/JPL-Caltech
NASA/JPL-Caltech

In October, scientists using the University of Hawaii's Pan-STARRS 1 telescope sighted something extraordinary: Earth's first confirmed interstellar visitor. Originally called A/2017 U1, the once-mysterious object has a new name—'Oumuamua, according to Scientific American—and researchers continue to learn more about its physical properties. Now, a team from the University of Hawaii's Institute of Astronomy has published a detailed report of what they know so far in Nature.

Fittingly, "'Oumuamua" is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's astronomical designation is 1I/2017 U1. The "I" in 1I/2017 stands for "interstellar." Until now, objects similar to 'Oumuamua were always given "C" and "A" names, which stand for either comet or asteroid. New observations have researchers concluding that 'Oumuamua is unusual for more than its far-flung origins.

It's a cigar-shaped object 10 times longer than it is wide, stretching to a half-mile long. It's also reddish in color, and is similar in some ways to some asteroids in own solar system, the BBC reports. But it's much faster, zipping through our system, and has a totally different orbit from any of those objects.

After initial indecision about whether the object was a comet or an asteroid, the researchers now believe it's an asteroid. Long ago, it might have hurtled from an unknown star system into our own.

'Oumuamua may provide astronomers with new insights into how stars and planets form. The 750,000 asteroids we know of are leftovers from the formation of our solar system, trapped by the Sun's gravity. But what if, billions of years ago, other objects escaped? 'Oumuamua shows us that it's possible; perhaps there are bits and pieces from the early years of our solar system currently visiting other stars.

The researchers say it's surprising that 'Oumuamua is an asteroid instead of a comet, given that in the Oort Cloud—an icy bubble of debris thought to surround our solar system—comets are predicted to outnumber asteroids 200 to 1 and perhaps even as high as 10,000 to 1. If our own solar system is any indication, it's more likely that a comet would take off before an asteroid would.

So where did 'Oumuamua come from? That's still unknown. It's possible it could've been bumped into our realm by a close encounter with a planet—either a smaller, nearby one, or a larger, farther one. If that's the case, the planet remains to be discovered. They believe it's more likely that 'Oumuamua was ejected from a young stellar system, location unknown. And yet, they write, "the possibility that 'Oumuamua has been orbiting the galaxy for billions of years cannot be ruled out."

As for where it's headed, The Atlantic's Marina Koren notes, "It will pass the orbit of Jupiter next May, then Neptune in 2022, and Pluto in 2024. By 2025, it will coast beyond the outer edge of the Kuiper Belt, a field of icy and rocky objects."

Last week, University of Wisconsin–Madison astronomer Ralf Kotulla and scientists from UCLA and the National Optical Astronomy Observatory (NOAO) used the WIYN Telescope on Kitt Peak, Arizona, to take some of the first pictures of 'Oumuamua. You can check them out below.

Images of an interloper from beyond the solar system — an asteroid or a comet — were captured on Oct. 27 by the 3.5-meter WIYN Telescope on Kitt Peak, Ariz.
Images of 'Oumuamua—an asteroid or a comet—were captured on October 27.
WIYN OBSERVATORY/RALF KOTULLA

U1 spotted whizzing through the Solar System in images taken with the WIYN telescope. The faint streaks are background stars. The green circles highlight the position of U1 in each image. In these images U1 is about 10 million times fainter than the faint
The green circles highlight the position of U1 in each image against faint streaks of background stars. In these images, U1 is about 10 million times fainter than the faintest visible stars.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Color image of U1, compiled from observations taken through filters centered at 4750A, 6250A, and 7500A.
Color image of U1.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Editor's note: This story has been updated.

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Scientists Analyze the Moods of 90,000 Songs Based on Music and Lyrics
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Based on the first few seconds of a song, the part before the vocalist starts singing, you can judge whether the lyrics are more likely to detail a night of partying or a devastating breakup. The fact that musical structures can evoke certain emotions just as strongly as words can isn't a secret. But scientists now have a better idea of which language gets paired with which chords, according to their paper published in Royal Society Open Science.

For their study, researchers from Indiana University downloaded 90,000 songs from Ultimate Guitar, a site that allows users to upload the lyrics and chords from popular songs for musicians to reference. Next, they pulled data from labMT, which crowd-sources the emotional valence (positive and negative connotations) of words. They referred to the music recognition site Gracenote to determine where and when each song was produced.

Their new method for analyzing the relationship between music and lyrics confirmed long-held knowledge: that minor chords are associated with sad feelings and major chords with happy ones. Words with a negative valence, like "pain," "die," and "lost," are all more likely to fall on the minor side of the spectrum.

But outside of major chords, the researchers found that high-valence words tend to show up in a surprising place: seventh chords. These chords contain four notes at a time and can be played in both the major and minor keys. The lyrics associated with these chords are positive all around, but their mood varies slightly depending on the type of seventh. Dominant seventh chords, for example, are often paired with terms of endearment, like "baby", or "sweet." With minor seventh chords, the words "life" and "god" are overrepresented.

Using their data, the researchers also looked at how lyric and chord valence differs between genres, regions, and eras. Sixties rock ranks highest in terms of positivity while punk and metal occupy the bottom slots. As for geography, Scandinavia (think Norwegian death metal) produces the dreariest music while songs from Asia (like K-Pop) are the happiest. So if you're looking for a song to boost your mood, we suggest digging up some Asian rock music from the 1960s, and make sure it's heavy on the seventh chords.

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