The planetary radar, one of the most important tools of the planetary defense system, set a historical record by observing the thousandth asteroid close to Earth./p>
August 14, 2021 was a special day for planetary scientists. On this day, a small asteroid, now called PJ1 2021, passed close to Earth and became the 1000th Near-Earth Asteroid (NEA) discovered by planetary radar.
The newly discovered small asteroid was more than 1.7 million kilometers long when it passed by the Earth, and with a width of about 20 to 30 meters, it was not considered a threat to the Earth. Proximity to Earth by this radar antenna is a historic event that reminds us of the importance of planetary defense. The budget for the Near-Earth Observatory Program was increased 10 years ago. The program is now part of NASA's Planetary Defense Program.
- NASA builds a space telescope to
protect Earth from asteroid impact "2021 PJ1 is a small asteroid,
so when it passed us more than 1.7 million kilometers away, we
could not get accurate radar images," said Lance Benner, astronomer
and head of NASA asteroid radar research programs. But planetary
radar is powerful enough even at such distances to detect it and
measure speed very accurately. "This has significantly improved our
knowledge of its future motion."
Asteroid Radar Research
Improving awareness of the future motion of asteroids is one of the highlights of NASA's Asteroid Radar Research Program . In recent decades, astronomers have discovered that asteroids and comets are potentially at risk of colliding with Earth, and even NASA conducts annual maneuvers to practice asteroid collisions. This year, for example, this maneuver had alarming results.
Goldstone Distant Space Network Center
Research to track asteroids and determine their characteristics continues even after the thousandth asteroid. Just days after the 1,000th radar-observed asteroid, NASA's Goldstone 70-meter antenna brought a larger asteroid to the attention of scientists on August 22, and as the asteroid passed close to Earth, its properties were accurately measured and photographed.
With this study, the 2016 asteroid AJ193 became the 1,000th near-Earth asteroid to be examined by planetary radar since the observation of the asteroid "Icarus 1566" in 1968. This huge space rock, which passed the closest distance to Earth on August 21, did not pose a threat to Earth, but it was close enough to be visible to amateur telescopes.
The space rock was an opportunity for scientists to study it from August 20 to 24 with the Goldstone Antenna near Barsto, California. They sent radio signals to the asteroid and analyzed its radar reflection or echo. The researchers found that the 2016 asteroid AJ193 orbits every 3.5 hours. The analysis also revealed good details of the body surface, such as bumps, small hills, flat spots, depressions, and possible boulders. It moves per hour relative to the earth. The asteroid's closest approach on August 21 was 3.4 million kilometers, 8.9 times the distance from the moon to Earth.
Shantanu Naidu of NASA's Jet Propulsion Lab "This asteroid follows the orbit of a comet, which indicates that it may be an inactive comet," said AJ193, who oversaw the 2016 AJ193 observatory. "Before this passage, we had little information about it and only the size and amount of light reflected from its surface."
Planetary Radar Data from Asteroid 2021 PJ1
According to NASA Scientists from The new 2016 AJ193 observatories will use it to better understand its size, shape, and composition, and like asteroid 2021 PJ1, measure its distance and velocity in this way, providing data that will reduce uncertainty in calculating its future orbit."Studies by ground-based and space-based telescopes to identify and track nearly 27,000 near-Earth objects in the solar system," said Kelly Fast of NASA's Office of Planetary Defense Coordination. Used. But in addition to optical telescopes, planetary radar is an important tool for observing asteroids approaching Earth. "
Radar detection of near-Earth asteroids underscores the important role that this scientific tool plays in identifying this dangerous population. "A contribution that is essential to our efforts to defend the planets."
Cover photo: 2016 AJ193 asteroid rotation, which was the 1000th asteroid observed by planetary radar.
Sources: EarthSky, Phys .Org