The project of the Virtual Telescope, based in Rome, Italy, captured the asteroid (99942) Apophis on March 2, 2021. The asteroid appears as a point – while the stars around it look like stripes – because the telescope was following the asteroid’s motion. It moves through space relative to Earth at 4,658 km / sec (2,894 miles / sec). Virtual telescope image.
Astronomers have turned their attention to the asteroid Apophis this week, as it makes the closest passage to Earth before the extremely close passage in 2029. It will be closest in 2021 between March 5-6, not in the same way. especially close to this time, but still within range of telescopes and ground radar. Apophis is an asteroid close to Earth, with a relatively large size (almost 400 meters, or yards, transverse). It sparked excitement in 2004, when early observations suggested it could hit Earth as it passes in 2029. Subsequently, a 2029 strike was ruled out, and Apophis is not expected to hit Earth in this century. But this asteroid is a frequent visitor to our space region, and astronomers want to know more.
The asteroid Apophis will sweep closest to our planet on March 6, 2021, at 01:15 UTC (March 5 at 20:15 EST; translate UTC to your time). At this 2021 step, it will reach 16,852,369 km (10,471,577 miles). This is about 44 times the distance of the moon, a very safe distance for this passage.
NASA’s Goldstone Deep Space Communications Complex in California has the asteroid in its observation program as of March 3, 2021 and intends to track it until March 14. Researchers at the Green Bank Telescope in West Virginia also began observing Apophis on March 3; Green Bank is coordinating observations with Goldstone because using these two telescopes together allows the data to be clearer. Of course, astronomers mourn the loss of Puerto Rico’s Arecibo telescope. Word on the street is that Arecibo – known for its radar observations of asteroids – would have been the best telescope in the world for observing Apophis this year. However, Arecibo suffered a crash last fall, which caused the telescope to be decommissioned. The International Asteroid Warning Network (IAWN) – which has members in Europe, Asia and South and North America – serves as a clearinghouse for the 2021 Apophis observation campaign. Its coordinator is astronomer Vishnu Reddy, an expert in planetary defense at the University of Arizona.
The Virtual Telescope Project in Rome offers a free online viewing session of the asteroid Apophis from March 5-6, 2021. Feeding will begin on March 6 at 00:00 UTC (March 5 at 19:00 EST; translate UTC at your time .).
Click here for more information on the live viewing of the Apophis Asteroid Virtual Telescope on March 5-6, 2021.
Previous observations with Goldstone and Arecibo radar observations have confirmed that Apophis has an elongated shape. Image via NASA / JPL.
In addition, astronomers plan to study the asteroid Apophis using NASA’s NEOWISE infrared space telescope in April 2021. This is the same telescope that discovered the 2020 favorite comet, NEOWISE Comet, which has now disappeared from view.
After passing through 2029, the asteroid Apophis will also make remarkable passes near Earth in 2036 and again in 2068. Earth strikes in 2029 and 2036 have been ruled out. As of February 2021, the chances of impact during the Apophis flight in 2068 are now 1 in 380,000. This is a 99.99974% chance that the asteroid will miss Earth in 2068.
Apophis’ observations from 2021 should further improve our knowledge of the asteroid’s shape and rotation and help reduce the uncertainties in the orbit of the space rock caused by what is called Yarkovsky acceleration.
In some cases, acceleration – a Change in the speed and direction of an object through space – can help avoid a collision. Studies on Yarkovsky’s acceleration in relation to the asteroid Apophis suggest that this is the case with this asteroid. Previous calculations (made in 2016) had all about ruled out an impact probability in 2068. The chance of an impact was seen in 2016 as very low, with only 1 in 150,000 chances of impact, or a 99.99933% chance that the asteroid would miss Earth.
More recent comments, first discussed in October 2020 and updated again in early 2021, show a decreasing risk.
It is a Yarkovsky acceleration of the Apophis asteroid – detected by astronomers at the University of Hawaii – that reduced the probability of impact for the 2068 flight.
The orbit of the asteroid Apophis (pink) as opposed to the orbit of Earth (blue). The yellow dot represents the sun. Apophis takes 323.6 days to orbit the sun. The earth lasts 365.3 days. Thus, this asteroid is a fairly frequent visitor to our space region. Image via Phoenix7777 / Wikimedia Commons.
Astronomer Dave Tholen and colleagues used the 323-inch (8.2-meter) Subaru Telescope in Maunakea, Hawaii, to make the latest observations. These astronomers then managed to update the Earth’s impact on Apophis, including the latest measurements of the Yarkovsky effect, which appears from a tiny push given by sunlight.
Visit the Apophis page at the Center for Earth Object Studies
The new paper by Tholen and colleagues suggests that Apophis – whose estimated diameter is between 1140 and 1,214 feet (340 to 370 meters) – derives more than 500 feet (about 170 meters) per year from its expected position. in its orbit.
Tholen has been tracking Apophis’ movement in the sky since he and his colleagues discovered it at the Kitt Peak National Observatory near Tucson, Arizona, on June 19, 2004. He commented in a statement:
We have known for some time that an impact with the Earth is not possible during the imminent approach of 2029.
The new observations I got with the Subaru telescope [in 2020] were good enough to reveal Apophis’ Yarkovsky acceleration and show that the asteroid is moving away from a purely gravitational orbit by about 170 meters [about 500 feet] per year, which is enough to keep the 2068 impact scenario in play.
These observations are not easy to obtain and analyze. Factors such as the distance of the asteroid at the time of observation, its composition, shape and surface characteristics all affect the result.
But astronomers are struggling to understand the orbit of the asteroid Apophis due to its close sneaking past our planet in this century and beyond.
Read more about the Yarkovsky effect: Pushing asteroids with sunlight
Of course, Apophis is not the only asteroid near Earth. In recent years, astronomers have been able to find and track many tiny asteroids sweeping near Earth. For example, on September 24, 2020, the asteroid 2020 SW swept even closer to us than our meteorological and television satellites, as well as other geostationary satellites, orbiting our planet about 35,900 km from Earth’s surface. Asteroid 2020 SW has reached about 7% of the Earth-moon distance. But it is estimated that the asteroid 2020 SW is only about 14 to 32 feet in diameter (about 4.5 to 10 meters). It is very small, unlike the asteroid Apophis.
This animation shows the distance between the asteroid Apophis and Earth at the time of the asteroid’s closest approach in 2029. The blue dots are artificial satellites orbiting our planet, and pink represents the International Space Station. Image by NASA / JPL-Caltech.
The passing of the asteroid Apophis in 2029. Apophis’ meeting with Earth on April 13, 2029, will be extremely close. The closest of 2029, Apophis will sweep just 37,725 km from our planet, or about 10% of the Earth-moon distance. It is very close to a space stone of over 340 meters! Lance Benner of NASA / JPL commented:
This will be the closest approach to something known today. (In 2029) Apophis will be visible to the naked eye for several hours, and the Earth’s tides are likely to change their state of rotation.
Friday, April 13, 2029, will be a time of spectacle for the asteroid Apophis, both for the general public and for astronomers. Apophis will get so close that it will be visible only to the helpless eye; something that almost never happens with asteroids. According to NASA, Apophis will first become visible in the southern hemisphere and will look like a stream of light moving in Australia during this close encounter. It will be over the Atlantic Ocean closest to Earth. It will move so fast that it crosses the Atlantic in just one hour and will cross the US in the late afternoon / early evening in the next hour. Calculations indicate that Apophis will reach a visual magnitude of 3.1 during this approach, comparable to the stars in the Little Chariot. In 2029, Apophis is expected to be visible to the naked eye in parts of Australia, West Asia, Africa and Europe.
Like many other asteroids, Apophis has been classified as a potentially dangerous asteroid by the Center for the Minor Planet of the International Astronomical Union. This only means that it is an asteroid whose orbit is occasionally close to Earth, which is large enough to cause “significant regional damage” in the event of an impact. A survey conducted by the NEOWISE spacecraft in 2012 suggested that there are 4,700 ± 1,500 potentially dangerous asteroids with a diameter greater than 100 meters.
According to some estimates, an asteroid the size of Apophis can be expected to hit Earth every 80,000 years.
As a result of the extremely tight approach of April 2029, the perturbations caused by the Earth’s gravity are expected to change the orbit of Apophis from Athens to the Apollo class. Image via NASA / JPL.
Conclusion: The asteroid Apophis will pass over Earth this week will be the closest before passing extremely close in 2029. Between March 5-6, 2021, the passage will be 44 times farther than the moon’s orbit. Apophis is a relatively large body, notable for its extremely close approaches to Earth in 2029, 2036, and 2068. Astronomers’ observations indicate that Apophis is extremely unlikely to reach Earth in this century.
Read more about the Yarkovsky effect: Pushing asteroids with sunlight
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