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Jasper Nance
Jasper Nance

Tardigrades Could Live on Earth Until the Sun Dies

Jasper Nance
Jasper Nance

In considering the relative brevity of human existence, astronomer Carl Sagan once wrote, "We are like butterflies who flutter for a day and think it is forever." The same could not be said of the microscopic animals known as tardigrades, which, scientists are now predicting in the journal Nature, could stick around on Earth until the Sun dies. 

The tardigrade, also known as the moss piglet or water bear, is an admirably durable little monster. It superpower is a sort of half-death state called cryptobiosis. When hard times come around, the tardigrade simply curls up, dries up, and mostly stops living, only to re-inflate and rejoin the world when conditions are more comfortable. Studies have shown that tardigrades can survive scorching heat, blistering cold, starvation, desiccation, radiation, and even the vacuum of space.

That's just on the individual level. There are more than 1000 different tardigrade species [PDF], and all have already been around for a long, long time. Scientists estimate that the first tardigrades appeared on the planet around 600 million years ago—about 370 million years before the first dinosaurs. The dinosaurs disappeared. The tardigrades kept on trucking. 

And according to the authors of the new paper, the moss piglets could just keep on trucking for another 10 billion years.

"A lot of previous work has focused on 'doomsday' scenarios on Earth—astrophysical events like supernovae that could wipe out the human race," co-author David Sloan of Oxford University said in a statement.

But humans are far from the toughest kids on the block. ("Human life is somewhat fragile to nearby events," as the researchers diplomatically put it.) Why not try to find out how sturdier species would fare in those same scenarios? To do so, the researchers calculated the effects of three doomsday events—an asteroid strike, a nearby supernova, and a gamma ray burst (another type of stellar explosion)—on tardigrades' environment and physiology.

You can probably guess what they discovered.

"Although nearby supernovae or large asteroid impacts would be catastrophic for people, tardigrades could be unaffected," Sloan said. "Therefore it seems that life, once it gets going, is hard to wipe out entirely. Huge numbers of species, or even entire genera may become extinct, but life as a whole will go on."

Co-author Rafael Alves Batista, also of Oxford, said his team's findings should expand the scope of what we might consider a "habitable planet."

"Tardigrades are as close to indestructible as it gets on Earth, but it is possible that there are other resilient species examples elsewhere in the universe. In this context there is a real case for looking for life on Mars and in other areas of the solar system in general. If tardigrades are Earth's most resilient species, who knows what else is out there."

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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 our 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 month, 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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