- 3732 - INTERSTELLAR - comets and largest asteroid. 25 asteroids with orbits completely within Earth’s orbit have been discovered to date. Finding asteroids in the inner Solar System is a daunting observational challenge. Astronomers have only two brief 10-minute windows each night to survey this area and have to contend with a bright background sky resulting from the Sun’s glare.
--------------------- 3732 - INTERSTELLAR - comets and largest asteroid
- Most asteroids miss Earth at a safe distance. Space rocks from other solar system may be crossing Earth's path every 10 years or so. Astronomers have confirmed that a suspicious space rock that hit Earth in 2014 came from another star system, predating the famous interstellar visitor “'Oumuamua” by three years.
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- The 3-foot-wide mini-asteroid, which entered Earth's atmosphere on January 8, 2014, at a very fast speed of 134,200 mph. It followed an odd trajectory, which suggested it may have come from outside the solar system. By modeling the rock's path into the past and assessing its gravitational interactions with planets in the solar system astronomers confirmed the tiny asteroid was a newcomer into the sun's corner of the Milky Way galaxy.
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- The confirmation makes the rock “CNEOS 2014-01-08“, the first known visitor from interstellar space, predating the famous 650-foot-wide asteroid 'Oumuamua that zipped past Earth in 2017.
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- Only one year later, astronomers discovered the second interstellar object, the 1,650-foot-wide comet “Borisov“. The short interval between those discoveries led astronomers to believe that smaller interstellar rocks, only feet or tens of feet wide, must be much more common in the solar system and even regularly cross paths with our planet.
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- The researchers believe that interstellar space rocks might hit Earth's atmosphere about once per decade. By extrapolating the trajectory of each meteor backward in time and analyzing the relative abundances of each meteor’s chemical isotopes, one can match meteors to their parent stars and reveal insights into planetary system formation.
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- CNEOS 2014-01-08 exploded above the ocean near Papua New Guinea and the scientists believe that some pieces of the rock may have survived the journey through Earth's atmosphere and fallen into the sea.
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- The researchers also suggest that such a high frequency of interstellar visitors throughout Earth's history could mean that the seeds of life that had sprouted on our planet in the past 3.5 billion years may have come from another star system.
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- Astronomers have revealed the unusual chemical composition inside 2I/Borisov, the interstellar comet that visited our solar system last year. A strange ingredient has provided new clues about where this traveling space rock originated.
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- Following the appearance of the interstellar object 'Oumuamua in 2017, this was the second object from another solar system ever discovered wandering through our cosmic neighborhood. The researchers found that the gas coming from the comet contained more carbon monoxide (CO) than has been detected in any other comet this close to the sun, less than 186 million miles.
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- The concentration of CO in the gas coming from this comet was between 9 and 26 times higher than in the average comet in our solar system. The scientists detected both CO and hydrogen cyanide (HCN).
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- They found a similar amount of HCN in 2I/Borisov that's found in other comets in our solar system, so that discovery wasn't much of a surprise. But the unexpectedly high quantities of CO offered a major clue as to where this comet came from. The comet must have formed from material very rich in CO ice, which is only present at the lowest temperatures found in space, below minus 420 degrees Fahrenheit.
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- If the gases reflect the composition of 2I/Borisov's birthplace, then it shows that it may have formed in a different way than our own solar system comets, in an extremely cold, outer region of a distant planetary system.
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- Astronomers believe it came from a cold region in a larger protoplanetary disk, or rotating disk of dust and gas around a young star from which planets and planetary objects form. Many of these disks extend well beyond the region where our own comets are believed to have formed, and contain large amounts of extremely cold gas and dust.
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- 2I/Borisov was traveling 21 miles per second when it zoomed through our solar system. Researchers think that, whichever solar system it came from, it was likely torn from that system by the gravity of a passing star or large planet. After a long trip through space, it has made history as one of only two interstellar visitors ever identified in our solar system.
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- Twilight observations have enabled astronomers to spot three near-Earth asteroids (NEA) hiding in the glare of the Sun. These NEAs are part of an elusive population that lurks inside the orbits of Earth and Venus. One of the asteroids is the largest object that is potentially hazardous to Earth to be discovered in the last eight years.
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- They have discovered three new near-Earth asteroids (NEAs) hiding in the inner Solar System, the region interior to the orbits of Earth and Venus. This is a challenging region for observations because asteroid hunters have to contend with the glare of the Sun.
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- One is a 1.5-kilometer-wide asteroid, “2022 AP7“, which has an orbit that may someday place it in Earth’s path. The other asteroids, “2021 LJ4 and 2021 PH27“, have orbits that safely remain completely interior to Earth’s orbit
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- 2021 PH27 is the closest known asteroid to the Sun. It has the largest general-relativity effects of any object in our Solar System and during its orbit its surface gets hot enough to melt lead.
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- The twilight survey have found two large near-Earth asteroids that are about
1 kilometer across, a size that we call planet killers. There are likely only a few NEAs with similar sizes left to find, and these large undiscovered asteroids likely have orbits that keep them interior to the orbits of Earth and Venus most of the time.
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- Such observations are very near to the horizon, meaning that astronomers have to observe through a thick layer of Earth’s atmosphere, which can blur and distort their observations.
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- When hunting for asteroids inside Earth’s orbit, the capability to capture both deep and wide-field observations is indispensable. Large areas of sky are required because the inner asteroids are rare, and deep images are needed because asteroids are faint and you are fighting the bright twilight sky near the Sun as well as the distorting effect of Earth’s atmosphere.
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- DECam can cover large areas of sky to depths not achievable on smaller telescopes, allowing astronomers to go deeper, cover more sky, and probe the inner Solar System in ways never done before.
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- Astronomers want to understand how asteroids are transported throughout the inner Solar System and how gravitational interactions and the heat of the Sun can contribute to their fragmentation.
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- Observing toward the inner Solar System is challenging for ground-based telescopes and impossible for space-based optical/infrared telescopes like NASA’s Hubble and JWST telescopes. The intense light and heat of the Sun would fry the sensitive electronics. For this reason, both Hubble and JSWT are always pointed away from the Sun.
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- Atria asteroids are the smallest group of near-Earth asteroids. Their orbits have an aphelion (farthest point from the Sun) smaller than Earth’s perihelion (nearest point to the Sun).
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- November 6, 2022 I NTERSTELLAR - comets and largest asteroid 3728
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