Archive for the ‘asteroid/comet impacts’ category: Page 5

Jan 3, 2023

Chicxulub crater might be the smoking gun for the dinosaurs’ end of days

Posted by in categories: asteroid/comet impacts, existential risks

Forged 66 million years ago, an enormous impact crater near Chixculub, Mexico, was left undiscovered until only a few short decades ago. But what caused it?

Millions of years ago, a dramatic mass extinction wiped out the dinosaurs.

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Dec 2, 2022

Megatsunami on Mars linked to an asteroid strike 3.4 billion years ago

Posted by in categories: asteroid/comet impacts, existential risks, mapping

The event is likened to the Chicxulub collision on Earth.

A study has found that the megatsunami that swept Mars around 3.4 billion years ago was caused by an asteroid strike on one of its oceans. The event is compared to the likes of the Chicxulub collision—which is believed to have wiped out dinosaurs from the face of the earth about 66 million years ago.

Researchers, led by Alexis Rodriguez of the Planetary Science Institute in Arizona, have also suggested that NASA’s Viking 1 Lander, which was deployed on a mission to find evidence of life on Mars in 1976, could have landed near the crater of this megatsunami.

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Nov 27, 2022

Cause of Cambrian Explosion — Terrestrial or Cosmic?

Posted by in categories: asteroid/comet impacts, biotech/medical, evolution, existential risks, genetics

We review the salient evidence consistent with or predicted by the Hoyle-Wickramasinghe (H-W) thesis of Cometary (Cosmic) Biology. Much of this physical and biological evidence is multifactorial. One particular focus are the recent studies which date the emergence of the complex retroviruses of vertebrate lines at or just before the Cambrian Explosion of ∼500 Ma. Such viruses are known to be plausibly associated with major evolutionary genomic processes. We believe this coincidence is not fortuitous but is consistent with a key prediction of H-W theory whereby major extinction-diversification evolutionary boundaries coincide with virus-bearing cometary-bolide bombardment events. A second focus is the remarkable evolution of intelligent complexity (Cephalopods) culminating in the emergence of the Octopus. A third focus concerns the micro-organism fossil evidence contained within meteorites as well as the detection in the upper atmosphere of apparent incoming life-bearing particles from space. In our view the totality of the multifactorial data and critical analyses assembled by Fred Hoyle, Chandra Wickramasinghe and their many colleagues since the 1960s leads to a very plausible conclusion – life may have been seeded here on Earth by life-bearing comets as soon as conditions on Earth allowed it to flourish (about or just before 4.1 Billion years ago); and living organisms such as space-resistant and space-hardy bacteria, viruses, more complex eukaryotic cells, fertilised ova and seeds have been continuously delivered ever since to Earth so being one important driver of further terrestrial evolution which has resulted in considerable genetic diversity and which has led to the emergence of mankind.

Nov 20, 2022

Ancient global ocean on Mars may have come from carbon-rich chondrite meteorites from the outer solar system

Posted by in categories: asteroid/comet impacts, existential risks

A team of researchers at the University of Copenhagen’s Center for Star and Planet Formation, working with colleagues from Université de Paris, ETH Zürich and the University of Bern, has found evidence suggesting that most of the water that made up an ancient global ocean on Mars came from carbon-rich chondrite meteorites from the outer solar system. The study is published in Science Advances.

Prior research has suggested that at one time, Mars was either mostly or entirely covered by a watery , and that the water came from gases seeping from below the surface and liquifying as they cooled. In this new effort, the researchers suggest the water more likely came from another source—meteorites traveling from the outer solar system.

The researchers came to this conclusion after studying fragments flung from the surface of Mars after asteroid strikes, which made their way to Earth as meteorites. The researchers studied 31 of them, looking most specifically for chromium isotopic fingerprints. Chromium-54 does not occur naturally on Mars; thus, its presence in crust samples from Mars would indicate that the surface had been struck by material from somewhere else.

Nov 12, 2022

Mars shows how even the simplest life forms can destroy their own planet

Posted by in categories: asteroid/comet impacts, climatology, evolution, existential risks

Microbial life may have resided within the first four kilometers of Mars’s porous crust.

Four billion years ago, the solar system was still young. Almost fully formed, its planets were starting to experience asteroid strikes a little less frequently. Our own planet could have become habitable as long as 3.9 billion years ago, but its primitive biosphere was much different than it is today. Life had not yet invented photosynthesis, which some 500 million years later would become its main source of energy. The primordial microbes — the common ancestors to all current life forms on Earth — in our planet’s oceans, therefore, had to survive on another source of energy.

Some of the oldest life forms in our biosphere were microorganisms known as “hydrogenotrophic methanogens” that particularly benefited from the atmospheric composition of the time. Feeding on the CO2 (carbon dioxide) and H2 (dihydrogen) that abounded in the atmosphere (with H2 representing between 0.01 and 0.1% of the atmospheric composition, compared to the current approximate of 0.00005%), they harnessed enough energy to colonize the surface of our planet’s oceans.

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Nov 8, 2022

‘Planet killer’ asteroid that evaded detection for years

Posted by in categories: asteroid/comet impacts, existential risks

Asteroids of this size are big enough to cause mass extinction events.

Nov 1, 2022

Huge ‘planet killer’ asteroid discovered — and it’s heading our way

Posted by in categories: asteroid/comet impacts, existential risks

Writing in the Astronomical Journal, lead study author Scott Sheppard and colleagues at the Carnegie Institution for Science in Washington say they have found three “rather large” asteroids, one of which – 2022 AP7 – crosses the Earth’s orbit, making it a potentially hazardous asteroid (PHA).

With a diameter of about 1.1km to 2.3km, the team say 2022 AP7 is the largest PHA discovered since 2014 and probably in the top 5% of the largest ever found.

“Any asteroid over 1km in size is considered a planet killer,” said Sheppard, adding that should such an object strike Earth, the impact would be devastating to life as we know it, with dust and pollutants kicked up into the atmosphere, where they would linger for years.

Oct 31, 2022

‘Planet killer’ asteroid spotted hiding in the sun’s glare

Posted by in categories: asteroid/comet impacts, existential risks

Astronomers have spotted three near-Earth asteroids that were lurking undetected within the glare of the sun. One of the asteroids is the largest potentially hazardous object posing a risk to Earth to be discovered in the last eight years.

The asteroids belong to a group found within the orbits of Earth and Venus, but they’re incredibly difficult to observe because the brightness of the sun shields them from telescope observations.

To avoid the sun’s glare, astronomers leaped at the chance to conduct their observations during the brief window of twilight. An international team spied the space rocks while using the Dark Energy Camera located on the Víctor M. Blanco 4-meter Telescope located at the Cerro Tololo Inter-American Observatory in Chile.

Oct 31, 2022

A skyscraper-sized ‘potentially hazardous’ asteroid will zip through Earth’s orbit on Halloween

Posted by in categories: asteroid/comet impacts, existential risks

A newly discovered, “potentially hazardous” asteroid almost the size of the world’s tallest skyscraper is set to tumble past Earth just in time for Halloween, according to NASA.

The asteroid, called 2022 RM4, has an estimated diameter of between 1,083 and 2,428 feet (330 and 740 meters) — just under the height of Dubai’s 2,716-foot-tall (828 m) Burj Khalifa, the tallest building in the world. It will zoom past our planet at around 52,500 mph (84,500 km/h), or roughly 68 times the speed of sound, according to NASA (opens in new tab).

Oct 25, 2022

NASA proved it can deflect an asteroid. But spotting them is tricky

Posted by in categories: asteroid/comet impacts, existential risks

The bad news is NASA estimates that it tracks only about 40 percent of the asteroids large enough that they could cause calamity if they were to hit Earth. To save us, the space agency needs fair warning — years, not months or weeks — to muster the defenses in space needed to safeguard the planet.

“As we say, we can’t do anything about them unless we know about them, and when they might be a concern for us,” Lindley Johnson, NASA’s Planetary Defense Officer, said in an interview.

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