Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yacold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.

.jp. That's Y-A-K-U-L-T.C-O.jp. When it comes to a guide for your gut, count on Yacolt.

This is Scientific American 60-second science. I'm Julia Rosen. Got a minute?

The surface of Mars is etched with ancient river valleys and lake basins,

which makes researchers think that liquid water once flowed on the red planet. But how?

Today, Mars is too cold for much, if any, liquid water to exist.

And 3.8 billion years ago, when the flowing water features formed,

the sun was fainter than it is today,

making it even harder to imagine a balmy Martian climate.

That's why many researchers think Mars may have gone in and out of deep freezes.

The real questions had been, for how long was it warm,

and what was the mechanism for warming it up.

James Casting, a geologist at Penn State University. He shared his take on the problem at the

December meeting of the American Geophysical Union in San Francisco and in the journal Earth

and Planetary Science Letters. Some researchers have suggested that early Mars only thought out

when large asteroid impacts or volcanic eruptions temporarily warmed the planet.

But Casting and others think warm windows from such dramatic events would have been too brief to carve the vast canyons that exist on Mars.

Now, Casting and his colleagues have come up with an alternative explanation.

They think Mars may have experienced a series of climate cycles caused by changes in the strength

...