- 2918 - MOON - mini-moon circling Earth? For only the second time in history, astronomers have discovered a new, natural-origin, minimoon orbiting the Earth. This minimoon, known as “2020CD3” (CD3 for short), was first discovered using data from the “Catalina Sky Survey“.
--------------------------- 2918 - MOON - mini-moon circling Earth?
- The “Catalina Sky Survey”, CD3’s, orbit was determined to be geo-centric a team of 23 astronomers worldwide was assembled to make careful observations of the object to determine its identity.
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- One of the main reasons for the careful nature of the identification process is the fact that we’ve been fooled before! Spent upper stage rocket boosters from lunar missions have been mistaken for asteroids in the past. Both Apollo 12 and the Chinese Chang’e 2 missions left upper stages in space that briefly passed for fake minimoons.
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- Another hilarious case of mistaking a human-made object for an asteroid is the legendary ESA Rosetta spacecraft observed by the Catalina Sky Survey in 2007 during a flyby of the Earth was briefly given the provisional asteroid designation of 2007 VN84. There’s something intensely entertaining about a spacecraft that was bound to visit a comet being mistaken for an asteroid.
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- Rosetta and its lander “Philae” at comet “67P/Churyumov-Gerasimenko“ on a flyby of Earth before reaching the comet, the spacecraft was also misidentified as an asteroid!
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- What is CD3 and how can we be sure it isn’t human-related space debris? Like all solar system objects, the minimoon experiences a slight pressure from the solar wind and solar radiation. This effect is directly proportional to the surface area of the object in question.
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- By measuring the size of an object and observing the deviation in its orbit from that predicted solely from the influence of gravity. Astronomers compare the surface area to the mass. For rocket boosters, which are hollow, the surface to mass ratio is much higher. ( I would like to see some of these calculations )
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- Another way to look at it is that the Sun has less influence on the orbit of CD3 than we would expect for anything human-made, leading us to determine that the object is solid. It is now thought that the object is made of some kind of silicate. Essentially it’s a space-rock.
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- How big is this new moon? Is this something to worry about? What would happen if the minimoon collided with the Earth?
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- This particular minimoon has a diameter of one or two meters. If it were to hit Earth, it would burn up in the atmosphere. Another reason to put your mind at ease is the fact that CD3 has already left the Earth
- It is by calculating the object’s path backward in time that we know it was a minimoon to begin with. It was discovered on its way out of the Earth-Moon system. Before it left, it had been captured for 2.7 years. According to simulations, an average minimoon would only be captured for about nine month, It is a longer capture time than we expected.
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- Not only did CD3 stick around longer than expected, it also rotated slower than most simulated minimoons do, with a rotation period of once every three minutes. Compared to an enormous object like a planet, that might seem fast, but given the tiny size of this object, it is a most leisurely spin.
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- CD3 is only the second natural minimoon discovered, the first being “2006 RH120“, found fourteen years earlier.
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- The upcoming Vera Rubin Observatory should blow the doors off of the rate of minimoon discovery. We would expect to find one every two or three months in the best case. With first light expected in 2021, we may very well be on the verge of a new era in minimoon astronomy.
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- The Vera Rubin Observatory under construction in 2017 was known as the Large Synoptic Survey Telescope or LSST at the time.
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- Objects like CD3 are particularly fascinating for astronomers. Unlike the minerals on Earth’s surface, which undergo various weathering and geological processes, asteroidal material is pristine. Objects like CD3 contain the oldest material in the solar system, and studying them in detail tells us about how the solar system was born and shaped.
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- Extraordinary discoveries in dark matter, gravitational waves, black holes, supernovae, and exoplanets all garner big headlines. These tremendous stories often inspire many of us to remark that we live in a golden era of astronomy. We shouldn’t overlook small, close-to-home discoveries like CD3. This couch-sized lump of space rock might be a little thing, but the current and future study of this and similar objects is a big deal.
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- Though orbitally benign compared to near-Earth asteroids, TNOs “Trans- Neptunian Objects” are exotic, ancient and scientifically important small bodies found orbiting along the icy edges of the outer solar system. Composed of various mixtures of both rock and icy compounds, TNOs constitute some of the most primitive bodies within our solar system, preserving pristine compounds including water, methane, and organic molecules, all formed from the earliest history of our solar system.
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- Since TNOs are incredibly distant, their motion across the night sky appears extremely slow, therefore requiring comparisons of images acquired over a few months’ time, compared to only minutes separating images in the search for near-Earth asteroids.
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- The COSSS project applies a new moving object detection process that filters through the images and automatically detects TNO candidates. The final step is for citizen scientists to validate any real objects from the false detections that inevitably arise from combinations of background stars, noise in the images, and cosmic rays.
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- Sophisticated algorithms automatically identify moving objects, but final validation still requires humans to discern the real signals from the false ones, and COSSS provides a simple computer interface and tutorial process for users to become quickly proficient.
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- This is where new discoveries and will be made, in addition to adding new measurements for known TNOs. While new discoveries are apt to result from hard-won user efforts, ‘re-discovering’ previously known TNOs helps to extend and refine their orbits, and is a highly beneficial contribution to the tracking process.
The potential for discovery and tracking of TNOs using CSS’ massive archive image database, and also recognized the need to share the validation workload, and especially the thrill of discovery with an active citizen scientist community.
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- The Catalina Sky Survey now welcomes everyone to learn more about TNOs and the farthest reaches of our solar system, and help the planetary science community discover and track these far-flung icy worlds.
The Catalina Sky Survey is based at the Lunar and Planetary Laboratory in the University of Arizona’s Planetary Science Department. CSS is a NASA funded project whose dedicated mission is to discover and track near-Earth objects.
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------------------------------------ Other reviews available:
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- 2527 - MOON - Take Me to the Moon. - Twin astronauts, Mark Kelly and Scott Kelly, were part of a survival experiment. From March 2015 to March 2016 Scott spent a year on the International Space Station while his brother, Mark, remained on Earth. In April 2019, the results of a 3 year study was published of what changed between them with the two different year experiences. Can we survive on he Moon?
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- 2919 - MOONS - in our solar system? The discovery of moons around another planet left centuries’ worth of astronomers desperate to learn more about what other natural satellites the solar system holds. Increasingly powerful telescopes and interplanetary spacecraft have revealed that there are many of the moons in the solar system and they are far stranger than anyone could have imagined.
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- 2791 - MOON - measuring the distance? - The distance to the Moon is 240,000 miles. I learned that in High School. Today the average distance is measured to be 238,856 miles. Actually that distance can be measured to within less than an inch.
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- 2752 - MOON - mining the Moon? Forty-five years have passed since humans last set foot on an extraterrestrial body. Now, the moon is back at the center of efforts not only to explore space, but to create a permanent, independent space-faring society.
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- 2450 - MOON - new analysis 50 years later. The Apollo missions brought back 200 pounds of rocks and soil samples. Half of these samples were locked in a vacuumed safe to be analyzed 50 years later with more advanced scientific instruments. New sample testing inspired these new theories about the formation of the Moon.
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- 2241 - Some Moon eclipse party trivia. Happened December 20 , 2019.
- 1902 - The Moon and angular momentum.
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- 1901 - Other moons around the planets.
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- 1900 - Moons in our Solar System. Totals 161.
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- 1704 - There are two sides to get a Full Moon. The size of the Moon is 27% the size of the Earth. However, the Moon is only 1.2% the mass of the Earth. To get a rocket to leave the Moon it needs to accelerate to only 5,400 miles per hour.
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- 1681 - Enceladus and Europa might support life? We have 173 moons orbiting our 8 planets. Over 150 asteroids also have orbiting satellites.
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- 1678 - Moon history from the beginning. The Moon has almost no atmosphere. You can count catering yourself on website “NASA Lunar Reconnaissance Orbiter” www.moonzoo.org The Moon is 250,000 miles away but these images are from only 400 miles away.
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- 1450 - Full Moon on Doug’s birthday.
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- 1291 - Two Moons over Miami. The early Universe was a chaotic place.
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- 1243 - What is behind the Man in the Moon? As the Moon cooled it preserved some water in the form of hydroxyl. The Moon is spiraling away in its orbit 1.5 inches each year.
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- 1651 - Moon may be the best habitats for life.
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- 64 - What you did not know about our Moon.
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- November 25, 2020 “MOON - mini-moon circling Earth?” 2918
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--------------------- --- Tuesday, December 1, 2020 ---------------------------
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