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Does Planet Nine exist? Astronomers point to new evidence

A new study concludes that a large, as-yet-unknown Planet Nine – an estimated 4 times the size of Earth and 10 times its mass – is influencing the behavior of an oddball object in the outer solar system.

When was Earth’s 1st snow?

A new study suggests our planet got its 1st snowfall about 2.4 billion years ago, after a lot of land rose swiftly from the sea and set off dramatic changes on Earth.

Is Pluto made of a billion comets?

By comparing data from the 1st-ever Pluto flyby and a 1st-ever comet rendezvous mission, scientists developed what they call the ‘giant comet’ model of Pluto formation.

Today in science: Kennedy’s moon speech

On May 25, 1961, John F. Kennedy gave a stirring speech to a joint session of Congress, inspiring a nation to land humans on the moon with a decade.

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Scientists track major freshwater change

‘What we are witnessing is major hydrologic change,’ they said. Over 14 years, Earth’s wet land areas got wetter. Dry areas got drier. They also reported multiple hot spots resulting from groundwater depletion.

Fly through the Orion Nebula

Take 3 minutes to fly through the spectacular Orion Nebula, in this new 3D visualization from NASA.

Astronomers scrutinize Black Widow pulsar

They observed 2 intense regions of radiation on this rapidly spinning pulsar some 6,500 light-years away. “Like seeing a flea on the surface of Pluto,” they said.

A space ant fires its lasers

A rare natural laser beaming from the heart of the spectacular Ant Nebula suggests the presence of a double star system.

Deneb is distant and very luminous

But – especially with last month’s 2nd data release from the Gaia satellite, whose job is measuring star distances – why don’t we know Deneb’s distance for certain?

A case against killing spiders

An entomologist explains why it’s a good idea to be nice to the spiders you encounter and consider a live-and-let-live policy.

Top tips for poison ivy

Summer is a great time to frolic in the woods, but look out for poison ivy, oak, and sumac! Top tips for summer itch-prevention.

Does Mars have a North Star?

Will future Mars explorers have a North Star to guide them?

A tiny helicopter for Mars 2020

“After the Wright Brothers proved 117 years ago that powered, sustained, and controlled flight was possible here on Earth, another group of American pioneers may prove the same can be done on another world.”