3 Billion Years Ago, the World Might Have Been a Waterworld, With No Continents At All

Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)

Evidence from an ancient section of the Earth’s crust suggest that Earth was once a water-world, some three billion years ago. If true, it’ll mean scientists need to reconsider some thinking around exoplanets and habitability. They’ll also need to reconsider their understanding of how life began on our planet.

Continue reading “3 Billion Years Ago, the World Might Have Been a Waterworld, With No Continents At All”

Halo Around a Pulsar could Explain Why We See Antimatter Coming from Space

Astronomers have been watching a nearby pulsar with a strange halo around it. That pulsar might answer a question that’s puzzled astronomers for some time. The pulsar is named Geminga, and it’s one of the nearest pulsars to Earth, about 800 light years away in the constellation Gemini. Not only is it close to Earth, but Geminga is also very bright in gamma rays.

Continue reading “Halo Around a Pulsar could Explain Why We See Antimatter Coming from Space”

Science Fiction Might Be Right After All. There Might Be Breathable Atmospheres Across the Universe

This view of Earth’s horizon was taken by an Expedition 7 crewmember onboard the International Space Station, using a wide-angle lens while the Station was over the Pacific Ocean. A new study suggests that Earth's water didn't all come from comets. Credit: NASA

The last few years has seen an explosion of exoplanet discoveries. Some of those worlds are in what we deem the “habitable zone,” at least in preliminary observations. But how many of them will have life-supporting, oxygen-rich atmospheres in the same vein as Earth’s?

A new study suggests that breathable atmospheres might not be as rare as we thought on planets as old as Earth.

Continue reading “Science Fiction Might Be Right After All. There Might Be Breathable Atmospheres Across the Universe”

We Know We’re Made of Stardust. But Did it Come From Red Giants?

We’ve all heard this one: when you drink a glass of water, that water has already been through a bunch of other people’s digestive tracts. Maybe Attila the Hun’s or Vlad the Impaler’s; maybe even a Tyrannosaurus Rex’s.

Well, the same thing is true of stars and matter. All the matter we see around us here on Earth, even our own bodies, has gone through at least one cycle of stellar birth and death, maybe more. But which type of star?

That’s what a team of researchers at ETH Zurich (Ecole polytechnique federale de Zurich) wanted to know.

Continue reading “We Know We’re Made of Stardust. But Did it Come From Red Giants?”

Landslides Work Differently on Mars, and Now We Might Know Why

Some landslides, both here on Earth and on Mars, behave in a puzzling way: They flow a lot further than friction should allow them too.

They can also be massive, including a well-preserved one in Valles Marineris that is the same size as the state of Rhode Island. Scientists have speculated that it might be so large because a layer of ice that existed in the past provided lubrication. But a new study suggests that no ice is needed to explain it.

Continue reading “Landslides Work Differently on Mars, and Now We Might Know Why”

Weekly Space Hangout: October 16, 2019 – Jeffrey Kargel Talks Climate Change on Earth and Beyond

Hosts:
Fraser Cain (universetoday.com / @fcain)

Allen Versfeld (https://www.urban-astronomer.com/ / @uastronomer)

Dr. Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg & ChartYourWorld.org)

Moiya McTier (https://www.moiyamctier.com/ / @GoAstroMo)

Jeff Kargel is a Senior Scientist at the Planetary Science Institute in Tucson, Arizona. He is a geologist, a glaciologist, and a planetary scientist. Climate change is a major thread, and that is what he is here today to talk about.

Continue reading “Weekly Space Hangout: October 16, 2019 – Jeffrey Kargel Talks Climate Change on Earth and Beyond”