Tag Archives: rocky

Tianwen-2: China’s Upcoming Missions to Two Rocky Bodies in the Solar System

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Artist impressions of Earth’s semi-satellite Kamo`oalewa, designated as the initial target for the Tianwen-2 mission

Addy Graham/University of Arizona

China is making final preparations to launch a spacecraft aimed at exploring asteroids and comets, seeking to gain insights into these celestial bodies in our solar system.

The Tianwen-2 mission, orchestrated by the China National Space Agency (CNSA), plans to collect 100 grams of samples from the asteroid Chuan West and return them to Earth. Following the sample retrieval, the probe will utilize Earth’s gravity to propel itself towards the comet 311P/Panstarrs, which will be observed remotely.

The mission is set for launch from the Xichang Satellite Launch Center in Sichuan Province on May 29th. While NASA’s Osiris-Rex and JAXA’s Hayabusa missions have previously returned asteroid samples, this marks China’s inaugural asteroid mission, including the return of rock samples, and potentially the first mission aimed at a unique type of celestial body known as quasi-satellites.

Quasi-satellites, like Kamo`oalewa, do not orbit the Earth in a traditional manner; instead, they follow orbits around the Sun that are similar to Earth’s, creating an oval path relative to our planet. This intriguing scenario has led scientists to theorize that this may be a remnant lunar mass ejected by an asteroid impact millions of years ago.

In contrast, 311P/Panstarrs has an asteroid-like orbit, encircling the Sun within the asteroid belt between Mars and Jupiter, yet possesses a tail that gives it a comet-like appearance. This is believed to be composed of dust and debris shed from its nucleus.

The CNSA has previously indicated that 311P/Panstarrs is a “living fossil,” crucial for studying the early material composition, formation processes, and evolutionary history of the solar system. Tianwen-2 aims to enhance our understanding of both Kamo`oalewa and 311P/Panstarrs. However, the findings will not be available immediately, as the spacecraft is expected to reach 311P/Panstarrs by 2034, and the Kamo`oalewa samples are anticipated to return to Earth in the latter half of 2027.

It remains uncertain what extent the CNSA will share these findings. Leah-Nani Alconcel from the University of Birmingham, UK, mentions that the mission outline is known but lacks detailed information. One of the objectives may involve examining the differences between asteroids and comets to gain better insights into the diverse bodies of our solar system; however, specific details remain elusive.

In her previous experience with CNSA’s Double Star Satellite, Alconcel expressed concerns about the institution’s ability to provide substantial scientific data. She states, “It was incredibly challenging to negotiate with [the CNSA]. There is no public repository for this data.”

She describes the mission as ambitious, noting that Kamo`oalewa is in a rotating behavior. Navigation algorithms may require powerful computing resources to process images and sensor data sent back to Earth for calculations. “If we always opt for favorable and stable objects, we won’t gain much knowledge,” she warns. “There are numerous potential challenges ahead.”

The CNSA has not responded to requests for comment from New Scientist.

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Source: www.newscientist.com

Ancient forests hidden beneath the Rocky Mountains emerge as ice melts.

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exposed white bark pine

Gregory Pederson

Melting ice in the Rocky Mountains has led to the discovery of a 5,900-year-old white bark pine forest. Scientists discovered more than 30 trees during an archaeological survey on Wyoming's Beartooth Plateau at about 3,100 meters above sea level, 180 meters above the current tree line.

This, he says, “allows us to learn about past conditions at high altitudes.'' Kathy Whitlock at Montana State University. Japanese white pine (Albicari pine) These plants needed to grow during warmer weather, she says, because they don't currently grow at this elevation.

To understand the history of the lost forests, Whitlock's team analyzed tree rings and used carbon dating to find out how old the forests were. They discovered that the tree lived between 5,950 and 5,440 years ago, a time when temperatures were steadily dropping.

Data from ice cores in places like Antarctica and Greenland suggest that these temperature drops were influenced by centuries of volcanic eruptions in the Northern Hemisphere. These produced enough aerial deposits to block sunlight and lower global temperatures until the environment became too cold for these high-altitude trees to survive.

Although the newly discovered tree was lying flat, it was in exceptional condition, indicating that it was rapidly preserved after death. Although there is no evidence of avalanche cover, there are traces consistent with the current expansion of the ice sheet.

Climate models suggest that more continuous volcanic eruptions occurred in Iceland 5,100 years ago, causing further temperature drops, team members say Joe McConnell at the Desert Research Institute in Nevada. These temperature drops led to the expansion of the ice belt, and “the fallen trees were buried in the ice and protected from the elements for the next 5,000 years,” he says.

Only in recent decades have temperatures warmed enough to free trees from their ice cellars. The current tree line is “likely to shift upward as temperatures rise in the coming decades,” Whitlock said.

“This discovery was made possible thanks to anthropogenic climate change. Rising temperatures are exposing areas that have been buried under ice for thousands of years,” she says. “While discoveries like this are scientifically interesting, they are also a sad reminder of how vulnerable alpine ecosystems are to climate change.”

“This study is a very elegant and careful use of a rare 'time capsule' that tells us not only about these mountain forests 6,000 years ago, but also about the climatic conditions that allowed them to exist.” '' he says. Kevin Antukaitis at the University of Arizona.

These trees are not the first such finds that researchers have unearthed from Rocky Mountain ice. Previous research had found “fragments of wooden shafts used for arrows and darts,” Whitlock said. One of the shafts has been radiocarbon dated to be more than 10,000 years old, “which tells us that people have been hunting in high-altitude environments for thousands of years,” she says.

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Source: www.newscientist.com

New Method Discovered by Astronomers for Detecting Water Oceans and Alien Life on Rocky Exoplanets

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Planets that are too close to their star (such as Venus) are too hot, and planets that are too far away (such as Mars) are too cold, but planets that are within the habitable zone have just the right temperature. Although great efforts have been made to identify planets in the theoretical habitable region of stars, until now there has been no way to know whether a planet really has liquid water. Now, astronomers from the University of Birmingham and the Massachusetts Institute of Technology have found that if an exoplanet’s atmosphere has less carbon dioxide than its neighbors, it may have liquid water on its surface. It was shown that it was suggested.

Artist’s impression of the super-Earth planet Ross 508b. Image credit: Sci.News.

Astronomers have detected more than 5,200 extrasolar worlds so far. Modern telescopes allow us to directly measure the distance from a planet to a star and the time it takes to complete one revolution.

These measurements help scientists infer whether a planet is within its habitable zone.

However, there was no way to directly confirm whether a planet was truly habitable, i.e. whether there was liquid water on its surface.

Throughout our solar system, astronomers can detect the presence of liquid oceans by observing glints, flashes of sunlight reflecting off liquid surfaces.

These glows, or specular reflections, have been observed, for example, on Saturn’s largest moon, Titan, and helped identify the moon’s large lakes.

However, detecting similar glows on distant planets is not possible with current technology.

But astronomer Julien de Witt of the Massachusetts Institute of Technology, astronomer Amaury Tryaud of the University of Birmingham and colleagues believe there is another habitable landform close to home that could be detected far away. I noticed something.

“Looking at what was happening to terrestrial planets in our own star system gave us an idea,” Tryaud said.

Venus, Earth, and Mars share similarities in that all three are rocky and live in relatively temperate regions relative to the Sun.

Earth is the only planet of the three that currently has liquid water. Researchers then noted another clear difference. That means there is significantly less carbon dioxide in Earth’s atmosphere.

“We think these planets formed in a similar way, and if we find a planet with less carbon than it does now, it must have gone somewhere else,” Tryaud said.

“The only process that can remove this much carbon from the atmosphere is a strong water cycle involving oceans of liquid water.”

In fact, Earth’s oceans have played a major and persistent role in absorbing carbon dioxide.

For hundreds of millions of years, the ocean has absorbed enormous amounts of carbon dioxide. This is about the same amount that remains in Venus’ atmosphere today.

This planetary effect has resulted in Earth’s atmosphere being significantly depleted in carbon dioxide compared to neighboring planets.

Dr. Frieder Klein, a researcher at the Woods Hole Oceanographic Institution, said: “On Earth, much of the carbon dioxide in the atmosphere is sequestered in seawater and solid rock over geological timescales; It has helped regulate climate and habitability for billions of years.” .

Astronomers reasoned that if a similar decrease in carbon dioxide was detected on a distant planet compared to a nearby planet, this would be a reliable signal of a liquid ocean and life on its surface. did.

“After an extensive review of the literature in many fields, from biology to chemistry to carbon sequestration related to climate change, we found that if carbon depletion is indeed detected, it is likely that liquid water and its effects are “We think this is likely a strong indication that this is a sign of life.” Dr. de Witt said.

In the study, the researchers developed a strategy to detect habitable planets by looking for traces of depleted carbon dioxide.

Such searches are ideal for “pea” systems, like our solar system, in which multiple terrestrial planets, all about the same size, orbit relatively close to each other.

The first step, the scientists suggest, is to confirm that a planet has an atmosphere by simply looking for the presence of carbon dioxide, which is expected to dominate the atmospheres of most planets.

“Carbon dioxide is a very strong absorber of infrared light and can be easily detected in the atmospheres of exoplanets,” Dr. de Witt said.

“The carbon dioxide signal could reveal the presence of an exoplanet’s atmosphere.”

Once astronomers determine that multiple planets in a system have atmospheres, they move on to measuring their carbon dioxide content to see if one planet has significantly less than the others.

If so, this planet is likely habitable, which means there is a large amount of liquid water on its surface.

However, habitable conditions do not necessarily mean that the planet is inhabited. To confirm whether life actually exists, the authors suggest that astronomers look for another feature in the planet’s atmosphere: ozone.

On Earth, plants and some microorganisms contribute to absorbing carbon dioxide, although to a lesser extent than the oceans. Nevertheless, as part of this process, living organisms release oxygen, which reacts with solar photons and turns into ozone. Ozone is a much easier molecule to detect than oxygen itself.

If a planet’s atmosphere shows signs of both ozone and carbon dioxide depletion, the planet may be habitable and inhabited by humans.

“If you see ozone, there’s a pretty good chance it’s related to carbon dioxide being consumed by life forms,” ​​says Tryaud.

“And if it’s life, it’s glorious life. It won’t be just a few bacteria. It’ll be a planetary-scale biomass that can process and interact with large amounts of carbon.”

The researchers believe NASA/ESA/CSA’s James Webb Space Telescope can measure carbon dioxide, and possibly ozone, in nearby multiplanetary systems like TRAPPIST-1, a seven-planet system orbiting a bright star. I’m guessing it is. Light years from Earth.

“TRAPPIST-1 is one of the few systems that can use the Web to study Earth’s atmosphere,” said Dr. de Witt.

“We now have a roadmap to finding habitable planets. If we all work together, we may make paradigm-changing discoveries within the next few years.”

of study It was published in the magazine natural astronomy.

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AHMJ triode other. Atmospheric carbon depletion as a tracer of water oceans and biomass in temperate terrestrial exoplanets. Nat Astron, published online on December 28, 2023. doi: 10.1038/s41550-023-02157-9

Source: www.sci.news