Posted on by Matt Williams

Satellites Watched a Huge Fireball Explode Above the Bering Sea Late Last Year

NASA's MODIS instrument, aboard the Terra satellite, captured this true-color image showing the remnants of a meteor's passage, seen as a dark shadow cast on thick, white clouds on Dec. 18, 2018. Credit: NASA GSFC

When a meteor strike the Earth’s atmosphere, a magnificent (and potentially deadly) explosion is often the result. The term for this is “fireball” (or bolide), which is used to describe exceptionally bright meteor explosions that are bright enough to be seen over a very wide area. A well-known example of this is the Chelyabinsk meteor, a superbolide that exploded in the skies over a small Russian town in February of 2013.

On December 18th, 2018, another fireball appeared in the skies over Russia that exploded at an altitude of about 26 km (16 mi) above the Bering Sea. The resulting debris was observed by instruments aboard the NASA Terra Earth Observation System (EOS) satellite, which captured images of the remnants of the large meteor a few minutes after it exploded.

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Posted on by Evan Gough

Rivers on Mars Flowed for More Than a Billion Years

A photo of a preserved river channel on Mars. The color is overlaid to show elevation, with blue being low and yellow being high elevation. Image Credit: NASA/JPL/Univ. Arizona/UChicago
A photo of a preserved river channel on Mars. The color is overlaid to show elevation, with blue being low and yellow being high elevation. Image Credit: NASA/JPL/Univ. Arizona/UChicago

The ancient climate of Mars is a mystery to scientists. Even with all we’ve learned about Mars, it’s still difficult to explain how lakes and rivers existed. A new study shows that Martian rivers were swollen with runoff and that they flowed far later into the planet’s history than previously thought.

The question is, how did the Martian climate create these conditions?

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Posted on by Matt Williams

SpaceX Releases a New Render of What the All-Steel Starship Will Look Like Returning to Earth

SpaceX's first detailed render of the Starship reentering Earth's atmosphere. Credit: SpaceX

The design for SpaceX’s Starship (aka. Big Falcon Rocket) is really starting to come together! Over the holidays, sections of the Starship Hopper (a miniature version of the Starship) were photographed being put together at the company’s South Texas Launch Site. By mid-January, the parts were fully-integrated, forming the body of the stainless-steel prototype that would test the spacecraft’s overall architecture.

What followed, earlier this month, were tests of the Starship’s hexagonal heat shields to determine if they would offer sufficient protection during re-entry. And now, in anticipation of the spacecraft’s eventual launch, SpaceX released an eye-popping new rendering of the Starship that shows what it would look like reentering Earth’s atmosphere.

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Posted on by Susie Murph

Weekly Space Hangout: March 27, 2019 – Dr. Amanda Hendrix, Director of NASA’s TREX

Hosts:
Fraser Cain (universetoday.com / @fcain)
Dr. Pamela Gay (astronomycast.com / cosmoquest.org / @starstryder)
Dr. Kimberly Cartier (KimberlyCartier.org / @AstroKimCartier )
Dr. Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg & ChartYourWorld.org)

Dr. Amanda R. Hendrix is a Senior Scientist with the Planetary Science Institute, based in Boulder.

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Posted on by Matt Williams

Maybe Self-Replicating Robot Probes are Destroying Each Other. That’s Why We Don’t See Them

SETI's Allen Telescope Array monitor the stars for signs of intelligent life (SETI.org)

During the 1940s, Hungarian-American scientist John von Neumann developed a mathematical theory for how machines could endlessly reproduce themselves. This work gave rise to the idea of “von Neumann probes“, a class of self-replicating interstellar probes (SRPs) that could be used to do everything from exploring the Universe to seeding it with life and intervening in species evolution.

Some have naturally suggested that this be a focus of SETI research, which would entail looking for signs of self-replicating spacecraft in our galaxy. But as is always the case with proposals like these, the Fermi Paradox eventually reasserts itself by asking the age-old question – “Where is everybody?” If there are alien civilizations out there, why haven’t we found any evidence of their SRPs?

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Posted on by Matt Williams

Asteroid Bennu has Already Thrown Material off into Space 11 Times Since OSIRIS-REx Arrived

This asteroid Bennu ejecting particles from its surface on January 19 was created by combining two images taken by the NavCam 1 imager onboard NASA’s OSIRIS-REx spacecraft. Credit: NASA/Goddard/University of Arizona/Lockheed Martin

On Dec. 31st, NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) rendezvoused with the asteroid 101955 Bennu. As part of an asteroid sample-return mission, NASA hopes that material from this near-Earth Asteroid (NEA) will reveal things about the history of the Solar System, the formation of its planets, and the origins of life on Earth.

Since the spacecraft established orbit around the asteroid, it has witnessed some interesting phenomena. This includes the first-ever close-up observations of particle plumes erupting from an asteroid’s surface. Since that time, the mission team has kept an eye out for these eruptions, which has allowed them to witness a total of 11 “ejection events” since the spacecraft first arrived.

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Posted on by Tammy Plotner

Messier 82 – the Cigar Galaxy

Hubble image of the Cigar Galaxy (Messier 82). Credits: NASA, ESA and the Hubble Heritage Team (STScI/AURA); Acknowledgment: J. Gallagher (University of Wisconsin), M. Mountain (STScI) and P. Puxley (National Science Foundation)

Welcome back to Messier Monday! Today, we continue in our tribute to our dear friend, Tammy Plotner, by looking at the Cigar Galaxy – also known as Messier 82!

During the 18th century, famed French astronomer Charles Messier noticed the presence of several “nebulous objects”  while surveying the night sky. Originally mistaking these objects for comets, he began to catalog them so that others would not make the same mistake. Today, the resulting list (known as the Messier Catalog) includes over 100 objects and is one of the most influential catalogs of Deep Space Objects.

One of these objects is the starbust galaxy known as Messier 82, which is also called the “Cigar Galaxy” because of its distinctive shape. Located about 12 million light-years away in the constellation Ursa Major, this galaxy’s starburst action is thought to have been triggered by interactions with the neighboring galaxy M81 (aka. Bode’s Galaxy).

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