The sun stripped away most of Mars' atmosphere billions of years ago, "Star Trek" is coming back to TV and the search for signs of intelligent life around a strangely dimming star has come up empty so far. Here are Space.com's top stories of the week.

The sun stripped away Mars' atmosphere long ago

New results from NASA's MAVEN spacecraft suggest that the Red Planet lost most of its carbon dioxide-dominated atmosphere — which had kept Mars relatively warm and allowed the planet to support liquid surface water — to space about 3.7 billion years ago. [Full Story: Mars Lost Atmosphere to Space as Life Took Hold on Earth]

'Star Trek' coming back to TV in 2017

Set phasers to stunned: CBS Television Studios announced Nov. 2 that a new "Star Trek" series will launch in January 2017, with the premiere episode airing on CBS's television network. The rest of the episodes of the as-yet-unnamed series will air first on CBS All Access, the studio's digital streaming arm. [Full Story: New 'Star Trek' TV Series Warps Into Action in 2017]

No signs of intelligent life yet around 'alien megastructure' star

Observations of a strangely dimming star hypothesized to possibly host an "alien megastructure" have not turned up signs of communications from an extraterrestrial civilization, although the chatter may simply be too faint to hear. [Full Story: What the Flux? No Sign of Aliens Around Strange, Dimming Star]

NASA probe zooms through plume of Saturn moon Enceladus

NASA's Cassini spacecraft came within just 30 miles (50 kilometers) of the Saturn moon Enceladus' surface on Oct. 28, passing through a plume of material that erupts from satellite's icy crust. Images captured during the flyby show the rough and wrinkled surface of Enceladus, and a backlit view of the erupting spray of material. [Full Story: Enceladus Flyby: See Cassini's Close-up Photos of Icy Saturn Moon]

Martian auroras may spread across entire sky

The first astronauts to set foot on Mars may be in for a spectacular sight: The entire night sky filled with glowing auroras. [Full Story: Gorgeous Auroras Could Light Up Entire Martian Sky]

More evidence tying cosmic impacts to mass extinctions

Over the past 260 million years, cratering rates on Earth have peaked every 26 million years or so, in tune with a previously noted cycle of mass-extinction events, a new study found. And five of the six largest impact craters known from the last quarter-billion years — including the 112-mile-wide (180 kilometers) crater associated with the demise of the dinosaurs 65 million years ago — were gouged out at roughly the same time that a mass extinction occurred. [Full Story: Death from Above: Mass Extinctions Tied to Comet Strikes]

NASA recruiting new astronauts

Calling all aspiring astronauts: NASA announced Nov. 4 that it will be accepting applications starting in December for its next round of astronaut training. [Full Story: Got the Right Stuff? NASA Is Recruiting New Astronauts]

New Horizons on its way to second Kuiper Belt object

The NASA probe that flew by Pluto in July is now all lined up for a potential close encounter with a second faraway object, in 2019. [Full Story: NASA Pluto Probe Sets Course for Second Flyby Target]

New radar images of Halloween asteroid

The 2,000-foot-wide (600 meters) asteroid 2015 TB145 looked startlingly like a giant skull in radar images captured by Puerto Rico's Arecibo Observatory on Oct. 30. But the space rock is not so haunting in newly released photos taken on Oct. 31, when 2015 TB145 cruised within 300,000 miles (480,000 kilometers) of Earth — about 1.3 times the distance from our planet to the moon. [Full Story: Halloween Asteroid Not So Spooky in New Photos]

Has dark matter always been dark?

Dark matter particles may have interacted extensively with normal matter long ago, when the universe was very hot, a new study suggests. [Full Story: Mysterious Dark Matter May Not Always Have Been Dark]

October 2014 Antares rocket explosion seen in spectacular new light

A series of newly released photos shows last year's explosion of a private cargo-carrying rocket in dramatic detail. [Full Story: Intense Antares Rocket Explosion Shown in Newly Released NASA Photos]

Terraforming Mars could be tougher than thought

The hopes of turning Mars into a more Earth-like planet have just taken a hit. New results from NASA’s MAVEN mission show that the Red Planet likely doesn’t have huge stores of carbon dioxide that could be reintroduced into the atmosphere to help change its climate. [Full Story: Bad News for Terraforming: Mars' Atmosphere Is Lost in Space]

Have astronomers found evidence of advanced aliens?

NASA's Kepler space telescope has detected something weird orbiting a nearby star. Is it evidence of an alien civilization, a clump of exocomets or something else? [Full Story: Has the Kepler Space Telescope Discovered an Alien Megastructure?]

Rivers on ancient Mars were dozens of miles long

The shape of pebbles photographed by NASA's Mars rover Curiosity suggests these rocks rolled along in Red Planet streams for dozens of miles billions of years ago. [Full Story: Pebbles on Mars Shaped by Ancient Long-Gone Rivers Dozens of Miles Long]

Amazing Pluto continues to puzzle scientists

Making sense of Pluto's giant ice mountains, geologically young ice plains and other intriguing characteristics is going to take some time, scientists say. [Full Story: Pluto Is Beautiful, Complex and Thoroughly Puzzling for Scientists]

Feasting black holes sound like static

If you could hear the stuff that swirls around black holes, superdense white dwarfs and young stars, it would sound like the empty spaces on the radio dial. [Full Story: Eavesdropping on Black Holes: Feasting Giants Sound Like Static]

Amazing video shows Jupiter's shrinking Great Red Spot

Amazing new maps of Jupiter by the Hubble Space Telescope reveal that the gas giant's Great Red Spot, a massive storm about twice the diameter of Earth, is slowing the speed at which it shrinks. [Full Story: Amazing Jupiter Video Shows Slowing Shrinkage of the Great Red Spot]

Exoplanet anniversary: First alien world found around sunlike stars 20 years ago

On Oct. 6, 1995, Michel Mayor and Didier Queloz of Switzerland's Geneva Observatory announced the discovery of the huge, scorching-hot 51 Pegasi b, the first alien planet ever found around a sunlike star. [Full Story: 20 Years On, Future Bright for Exoplanet Science]

North pole of Saturn's ocean-harboring moon Enceladus unveiled

NASA's Cassini spacecraft has captured its best-ever looks at the north polar region of Saturn's ocean-harboring moon, Enceladus. [Full Story: North Pole of Saturn's Icy Moon Enceladus Captured in Best-Ever Photos]

Famed planet hunter Geoff Marcy resigns

Geoff Marcy, a leader in the field of exoplanet research, has resigned from his position as a professor of astronomy at the University of California, Berkeley, following an investigation that found he violated the school's sexual harassment policies. [Full Story: Planet Hunter Geoff Marcy Resigns Following Sexual Harassment Investigation]

'The Martian' gets space exploration right

The film adaptation of Andy Weir's breakout novel "The Martian" isn't just awesome, it might also be one of the most realistic space exploration movies that's ever graced the silver screen. [Full Story: 'The Martian' Might Be the Most Realistic Space Movie Ever Made]

Do aliens have sex?

Humans love to ponder whether alien life is out there, and what it might look like. So here's a burning question: Would extraterrestrials have sex? [Full Story: If Aliens Exist, Would They Have Sex?]

Should rovers explore wet areas on Mars?

The revelation that dark streaks flowing downhill on Mars are signs of present-day liquid water has sparked debate about how best to investigate the Red Planet features. [Full Story: Mars Water Discovery Sparks Exploration Debate]

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