asteroids (4)

Ceres...

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Occator Crater and Ahuna Mons appear together in this view of the dwarf planet Ceres obtained by NASA's Dawn spacecraft on February 11, 2017. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/Handout via REUTERS.

Topics: Asteroids, Exoplanets, Space Exploration, Spaceflight

"Ceres was the Roman goddess of agriculture, grain, and the love a mother bears for her child. She was the daughter of Saturn and Ops, the sister of Jupiter, and the mother of Proserpine. Ceres was a kind and benevolent goddess to the Romans and they had a common expression, "fit for Ceres," which meant splendid." Source: Ceresva.org

WASHINGTON (Reuters) - Ceres, the largest object in the asteroid belt between Mars and Jupiter, is an “ocean world” with a big reservoir of salty water under its frigid surface, scientists said in findings that raise interest in this dwarf planet as a possible outpost for life.

Research published on Monday based on data obtained by NASA’s Dawn spacecraft, which flew as close as 22 miles (35 km) from the surface in 2018, provides a new understanding of Ceres, including evidence indicating it remains geologically active with cryovolcanism - volcanoes oozing icy material.

The findings confirm the presence of a subsurface reservoir of brine - salt-enriched water - remnants of a vast subsurface ocean that has been gradually freezing.

“This elevates Ceres to ‘ocean world’ status, noting that this category does not require the ocean to be global,” said planetary scientist and Dawn principal investigator Carol Raymond. “In the case of Ceres, we know the liquid reservoir is regional scale but we cannot tell for sure that it is global. However, what matters most is that there is liquid on a large scale.”

Dwarf planet Ceres is 'ocean world' with salty water deep underground, Will Dunham, Reuters Science

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The Whims of Tyche...

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Fossil of trilobite that evolved following the mid-Ordovician ice age. | Birger Schmitz

 

Topics: Asteroids, Astronomy, Biology, Planetary Science


Tyche: Modern Greek: [ˈti.çi] "luck"; Roman equivalent: Fortuna) was the presiding tutelary deity who governed the fortune and prosperity of a city, its destiny. In Classical Greek mythology, she is the daughter of Aphrodite and Zeus or Hermes. Source: Wikipedia

Dust from the breakup of a 150-kilometer- (93 mile) diameter asteroid may have caused — or at least intensified — an ice age half a billion years ago, providing the impetus for a sweeping array of aquatic animal adaptations that shaped today's spectacularly diverse ocean ecosystems, according to a new study published in the September 20 issue of Science Advances.

The authors uncovered extraterrestrial material in sediments that correlate the timing of asteroid breakup with a major dip in sea level frequently attributed to the onset of the Mid-Ordovician ice age. Their findings suggest that asteroid dust may have settled in Earth's atmosphere, shading the planet from the sun's radiation and cooling global temperatures.

While extraterrestrial dust only accounts for about one percent of the modern atmosphere and does not impact the climate, large quantities of dust lingering for several hundred thousand years or more would be expected to cause global cooling.

"This is the first time anyone has shown that asteroid breakups and asteroid dust can lead to ice ages," said Birger Schmitz, a professor of geology at Lund University in Sweden and the first author of the study. "This is also the first time since the discovery of the asteroid impact that killed the dinosaurs that an important event in the history of life has been tied to an astronomical event."

 

Asteroid Dust May Have Triggered Ice Age and Sea Life Explosion
Shannon Kelleher, American Association for the Advancement of Science

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Asteroid Stuff...

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An artist's depiction of an asteroid collision in outer space.(Image: © Don Davis, Southwest Research Institute)

 

Topics: Asteroids, Astrobiology, Planetary Exploration, Planetary Science


"We are made of star stuff." Carl Sagan

Consider the possibility that an asteroid may have transformed the picture of life on Earth — but forget the dinosaurs and the massive crater, and rewind an extra 400 million years from that dramatic moment.

Back then, life was primarily an oceanic affair and backbones were the latest in arrival on the anatomy scene. But unlike the asteroid that killed the dinosaurs 66 million years ago, this earlier space rock never made it to Earth. Instead, a collision in the asteroid belt flooded the solar system with so much dust that, given some other changes at the time, allowed life on Earth to flourish, new research suggests.

"Most important events in the history of life are like that," said Rebecca Freeman, a paleontologist at the University of Kentucky who specializes in this period but wasn't involved in the new research. "You get a really unique set of circumstances that all come together, and you get a really dramatic event that maybe seems like it should be due to one particular dramatic thing. But in reality, it's a more complicated system at play," she told Space.com.

The dramatic event scientists want to explain is a spree of new species. That outburst of life, which paleontologists call the Great Ordovician Biodiversification Event, took place in the oceans, which were inhabited mostly by spineless creatures. "This is really a world that is dominated by invertebrate marine organisms," Freeman said. "Probably the top predator would have been a cephalopod," likely an ancestral relative of today's chambered nautilus, with its intricate spiral shell.

But when Birger Schmitz, a geologist at Lund University in Sweden, went hunting for rock dating back 466 million years, he wasn't hoping to find fossilized nautiluses; he was looking for fossilized meteorites. And over the past couple of decades, he and his colleagues have found dozens of these fossilized meteorites in a Swedish limestone quarry. Each carries a chemical time stamp indicating that it was heated about 470 million years ago, and scientists have thought for a while that there might have been a massive asteroid collision around that time.

 

Asteroid Dust Triggered an Explosion of Life on Earth 466 Million Years Ago
Meghan Bartels, Space.com

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Off-World Ventures...

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A scheme to beam solar power entails collecting sunlight and beaming it to Earth. An array of mirrored heliostats (conical structure) collects the sunlight, and a photovoltaic array (disk) converts it into electricity, which is then converted into a coherent microwave beam and sent to receivers almost anywhere in view on Earth. The image depicts the SPS-ALPHA, or Solar Power Satellite by means of Arbitrarily Large Phased Array.

 

Topics: Asteroids, Economics, Space Exploration, Spaceflight


An apparent confluence of political will and technological readiness has fans of humankind’s expansion beyond Earth hopeful that their dreams may soon become reality. Alongside a rise in missions to the Moon by agencies and private companies in the US, Europe, China, Japan, India, and Russia, commercial sectors are buzzing with related activities. And various governmental and nongovernmental bodies are strategizing about environmental, ethical, legal, sociological, and other issues of space utilization and colonization.

With interest in space travel growing—spurred in part by billionaire entrepreneurs such as Jeff Bezos and Elon Musk—enthusiasts say the time is right to figure out how to use space resources, including water, solar power, and lunar regolith. Doing so would expand space exploration, increase commercial activities in space, and lead to technological advances for humanity, says Angel Abbud-Madrid, director of the first graduate degree program in space resources, which he and colleagues launched last year at the Colorado School of Mines.

The only space resource exploited to date is the view of Earth from orbit for such applications as global positioning systems, weather prediction, communications, and science missions. A few years ago the prospect of mining asteroids for platinum and other metals to use on Earth was “the rage,” says George Sowers of the Colorado School of Mines. But the business case didn’t hold up. One exception might be rare-earth elements, but in the near to mid term, he says, “bringing stuff back to Earth is not economically viable.” For now, the focus has shifted to using space resources in situ.

Water is a primary target resource in space. Electrolyzed into hydrogen and oxygen, it becomes fuel that could replenish satellites in orbit and propel rockets for exploring the solar system and returning to Earth. Astronauts and space tourists could drink water, use it for gardening and hygiene, and shield themselves from ionizing radiation with meter-thick sheaths of it around habitats or spacecraft.

 

Prospect of off-planet outposts spurs interest in space resources
Toni Feder, Physics Today

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