नासा ने सूर्य के कारण कुछ क्षुद्रग्रहों को जल्दी खोजा – ‘हम हैरान थे’

द्वारा

यह क्षुद्रग्रह बेन्नू मोज़ेक नासा के OSIRIS-REx अंतरिक्ष यान द्वारा अवलोकनों का उपयोग करके बनाया गया था, जो दो साल से अधिक समय से क्षुद्रग्रह के करीब है। श्रेय: NASA/गोडार्ड/एरिज़ोना विश्वविद्यालय

हाल ही में, विद्वानों नासा का OSIRIS-REx मिशन उन्होंने पाया कि पृथ्वी की तुलना में क्षुद्रग्रहों पर सतह का नवीनीकरण बहुत तेजी से होता है। क्षुद्रग्रह बेन्नू पर रॉक फ्रैक्चर की उच्च-रिज़ॉल्यूशन छवियों का विश्लेषण करके, द्वारा लिया गया[{” attribute=””>OSIRIS-REx spacecraft, the researchers discovered that the Sun’s heat fractures rocks on Bennu in only 10,000 to 100,000 years. With the use of this knowledge, scientists will be able to better predict the time it takes boulders on asteroids like Bennu to fragment into smaller pieces, some of which may eject into space while others may remain on the asteroid’s surface.

Although tens of thousands of years might sound pretty slow, “we thought surface regeneration on asteroids took a few millions of years,” said Marco Delbo, senior scientist at Université Côte d’Azur, CNRS, Observatoire de la Côte d’Azur, Laboratoire Lagrange, Nice, France, and lead author of a paper published in June 2022 in the journal Nature Geoscience. “We were surprised to learn that the aging and weathering process on asteroids happens so quickly, geologically speaking.”

Although landslides, volcanoes, and earthquakes may abruptly alter the Earth’s surface, most changes occur gradually. Over millions of years, water, wind, and temperature changes slowly erode rock to create new surfaces. For instance, if you hiked into the Grand Canyon, you would see distinct rock layers; the top layers tend to be the youngest rocks, dating around 270 million years old, and the layers at the bottom of the canyon are the oldest, about 1.8 billion years old. The Colorado River has been chiseling away at rocks in the Grand Canyon for 5 million to 6 million years, according to the U.S. National Park Service.

Bennu Surface PolyCam

The PolyCam aboard NASA’s OSIRIS-REx spacecraft provided high-resolution, microscope-like images of asteroid Bennu’s surface. This made it possible for researchers to map more than 1,500 rock fractures. Credit: NASA/Goddard/University of Arizona

Rapid temperature changes on asteroid Bennu create internal stress that fractures and breaks down rocks, comparable to how a cold glass breaks under hot water. On Bennu, the Sun rises every 4.3 hours. At the equator, daytime highs can reach almost 260°F (about 127°C), and nighttime lows plummet to nearly minus 10°F (about minus 23°C).

OSIRIS-REx scientists spotted cracks in the rocks in spacecraft images from the first surveys of the asteroid. All of the fractures seemed to point in the same direction, “a distinct signature that temperature shocks between the day and the night could be the cause,” said Delbo.

Bennu Surface PolyCam Fractures Highlighted

Same image as above, but with the fractures highlighted in red. Credit: NASA/Goddard/University of Arizona

Delbo and his colleagues measured the length and angles of more than 1,500 fractures in OSIRIS-REx images by hand: some shorter than a tennis racket, others longer than a tennis court. They found the fractures predominantly align in the northwest-southeast direction, indicating they were caused by the Sun, which is shown here to be the primary force changing Bennu’s landscape.

“We were surprised to learn that the aging and weathering process on asteroids happens so quickly, geologically speaking.” — Marco Delbo

“If landslides or impacts were moving boulders faster than the boulders were cracking, the fractures would point in random directions,” said Delbo.

The research team used a computer model and their fracture measurements to calculate the 10,000- to 100,000-year timeframe for thermal fractures to propagate and split rocks.

“The thermal fractures on Bennu are quite similar to what we find on Earth and on Mars in terms of how they form,” said Christophe Matonti, a co-author of the paper at Université Côte d’Azur, CNRS, Observatoire de la Côte d’Azur, Géoazur, Sophia-Antipolis, Valbonne, France. “It is fascinating to see that they can exist and are similar in very ‘exotic’ physical conditions [low gravity, no atmosphere]मंगल की तुलना में भी।

जेसन ड्वॉर्किन, ओएसआईआरआईएस-आरईएक्स परियोजना वैज्ञानिक नासा का गोडार्ड स्पेस फ्लाइट सेंटर ग्रीनबेल्ट, मैरीलैंड में।

ओएसआईआरआईएस-आरईएक्स (उत्पत्ति, वर्णक्रमीय व्याख्या, संसाधन पहचान, सुरक्षा-रेगोलिथ एक्सप्लोरर) बेन्नू का नमूना धरती पर लौटाएंगे 24 सितंबर, 2023 को। “हम सतह की उम्र के बारे में अधिक विवरण जानने में सक्षम होंगे जब हम सीधे नमूने का अध्ययन करने में सक्षम होंगे,” ड्वर्किन ने कहा।

संदर्भ: मार्को डेल्पो, केविन जे वॉल्श, क्रिस्टोफ मैटोंटी, जस्टिन विल्करसन, मौरिज़ियो पैगोला, मनार द लायन, क्रिसा एवडेलिडो, रोनाल्ड लुईस ब्लूज़, करीना ए बेनेट, हेरोल्ड द्वारा “बेन्नू चट्टानों पर फ्रैक्चर का संरेखण तेजी से क्षुद्रग्रह सतह के विकास का संकेत”। C. कोनोली जूनियर और डेनिएला डेलागोस्टिना और डैथॉन आर। प्राकृतिक पृथ्वी विज्ञान.
डीओआई: 10.1038 / एस41561-022-00940-3

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