Did a Comet Wipe out the Dinosaurs?

Artist's rendering of a comet headed towards Earth. Public domain illustration.

About 66 million years ago a massive chunk of rock slammed into Earth in what is the modern-day Yucatan Peninsula. The impact extinguished about 75% of all life on Earth. Most famously, it was the event that wiped out the dinosaurs.

While mainstream scientific thought has pointed to an asteroid as the impactor, a new research letter says it could’ve, in fact, been a comet.

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We Could Find Extraterrestrial Civilizations by Their Air Pollution

Exoplanet Kepler 62f would need an atmosphere rich in carbon dioxide for water to be in liquid form. Artist's Illustration: NASA Ames/JPL-Caltech/T. Pyle

Upcoming telescopes will give us more power to search for biosignatures on all the exoplanets we’ve found. Much of the biosignature conversation is centred on biogenic chemistry, such as atmospheric gases produced by simple, single-celled creatures. But what if we want to search for technological civilizations that might be out there? Could we find them by searching for their air pollution?

If a distant civilization was giving our planet a cursory glance in its own survey of alien worlds and technosignatures, they couldn’t help but notice our air pollution.

Could we turn the tables on them?

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NASA’s Perseverance Rover: The Most Ambitious Space Mission Ever?

Artist's impression of the Perseverance rover on Mars. Credit: NASA-JPL

When it comes to Mars exploration, NASA has more success than any other agency. This week, they’ll attempt to land another sophisticated rover on the Martian surface to continue the search for evidence of ancient life. The Mars Perseverance rover will land on Mars on Thursday, February 18th, and it’s bringing some very ambitious technologies with it.

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Perseverance Will Make Sure it has a Safe Landing

Mars 2020’s Perseverance rover is equipped with a lander vision system based on terrain-relative navigation, an advanced method of autonomously comparing real-time images to preloaded maps that determine the rover’s position relative to hazards in the landing area. Divert guidance algorithms and software can then direct the rover around those obstacles if needed. Credit: NASA/JPL-Caltech

To casual observers, landing a rover on Mars can seem kind of like old news, believe it or not. Especially after all of NASA’s successes. But many are likely not aware of the so-called ‘Mars Curse.‘ The fact is, many of the spacecraft that attempt to land there fail and crash.

Next to run the gauntlet of the Mars Curse is NASA’s Perseverance rover. It’ll attempt its long-awaited landing at Jezero Crater on February 18th. The people at NASA have given the Perseverance rover some finely-tuned tools to get it to the Martian surface safely and to beat the Mars curse.

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Possible Super-Earth in the Habitable Zone at Alpha Centauri

Kepler-22b, seen in this artist's rendering, is a planet a bit larger than Earth that orbits in the habitable zone of its star. Some researchers think there might be "superhabitable" worlds that may not resemble Earth. c. NASA

Astronomers using a new technique may have not only found a super-Earth at a neighbouring star, but they may also have directly imaged it. And it could be nice and cozy in the habitable zone around Alpha Centauri.

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A New Supernova Remnant Found from an Exploding White Dwarf Star

Astronomers have spotted the remnant of a rare type of supernova explosion. It’s called a Type Iax supernova, and it’s the result of an exploding white dwarf. These are relatively rare supernovae, and astronomers think they’re responsible for creating many heavy elements.

They’ve found them in other galaxies before, but this is the first time they’ve spotted one in the Milky Way.

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Astronomers Can Predict When a Galaxy’s Star Formation Ends Based on the Shape and Size of its Disk

An ensemble of twenty-five disk galaxies. The view on the left shows light emitted in the H-alpha line from interstellar gas as a result of ongoing star-formation, while the panels on the right shows the optical light emitted by a mix of young (bluer) and old (redder) stars. Each galaxy can be seen rotated edge-on below its face-on view. Image Credit: TNG Collaboration

A galaxy’s main business is star formation. And when they’re young, like youth everywhere, they keep themselves busy with it. But galaxies age, evolve, and experience a slow-down in their rate of star formation. Eventually, galaxies cease forming new stars altogether, and astronomers call that quenching. They’ve been studying quenching for decades, yet much about it remains a mystery.

A new study based on the IllustrisTNG simulations has found a link between a galaxy’s quenching and its stellar size.

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It Looks Like Iceberg A-68A is Coming Apart

A-68 iceberg positions as seen by Copernicus Sentinel-3 mission on January 30 2021. Image Credit: ESA

Iceberg A-68A, the massive frigid behemoth posing a threat to South Georgia Island, might be breaking into pieces. Satellite images from the European Space Agency showed large cracks forming in the iceberg.

Now it appears to breaking apart.

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The Earth’s Magnetosphere Might be Creating Water on the Moon

Artist’s depiction of the Moon in the magnetosphere, with “Earth wind” made up of flowing oxygen ions (gray) and hydrogen ions (bright blue), which can react with the lunar surface to create water. The Moon spends >75% of its orbit in the solar wind (yellow), which is blocked by the magnetosphere the rest of the time. Credit: E. Masongsong, UCLA EPSS, NASA GSFC SVS.

There’s no doubt that the Moon has water on its surface. Orbiters have spotted deposits of ice persisting in the perpetual shadows of polar craters. And recent research shows that water exists in sunlit parts of the Moon, too.

Over the years, scientists have presented evidence that the Moon’s water came from comets, from asteroids, from inside the Moon, and even from the Sun.

But now new research is pointing the finger directly at Earth as the source of some of the Moon’s water.

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When Galaxies Collide, Black Holes Don’t Always Get the Feast They Were Hoping for

galaxies collide
This illustration shows a stage in the predicted merger between our Milky Way galaxy and the neighboring Andromeda galaxy, as it will unfold over the next several billion years. In this image, representing Earth's night sky in 3.75 billion years, Andromeda (left) fills the field of view and begins to distort the Milky Way with tidal pull. (Credit: NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas; and A. Mellinger)

What happens when galaxies collide? Well, if any humans are around in about a billion years, they might find out. That’s when our Milky Way galaxy is scheduled to collide with our neighbour the Andromeda galaxy. That event will be an epic, titanic, collision. The supermassive black holes at the center of both galaxies will feast on new material and flare brightly as the collision brings more gas and dust within reach of their overwhelming gravitational pull. Where massive giant stars collide with each other, lighting up the skies and spraying deadly radiation everywhere. Right?

Maybe not. In fact, there might be no feasting at all, and hardly anything titanic about it.

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