we know more about Apophis, which will touch the Earth in 2029

Apophis. It was discovered in June 2004. asteroid about 350 meters and about 27 million tons. And for weeks, the scientific community has been worried about a possible impact with our Earth in April 2029. Just a few weeks. Because since December 2004, archival data has shown that a collision is unlikely. And new data collected since then – in particular on the occasion of the passage of Apophis just 17 million kilometers from our Earth on March 6, 2021 – has further eliminated the risk. I’asteroid orbit is now sufficiently certain to rule out any influence with certainty for at least a hundred years.

“Collision is not the only possibility in such events”says Gabriel Berderes-Motta, Research Fellow at the University of Madrid (Spain), in reported. “The gravitational interaction between a planet and a body like Apophis could change the shape of the body, shatter it into pieces, shatter any loose rocks on the asteroid’s surface, or even destroy other bodies orbiting the planet. or rings). »

Together with his team, he analyzed the physical characteristics of Apophis. His form. As well as its gravitational field. And factors that could affect its trajectory and angle of inclination. That radiation pressure, For example. Or outrage over his passages in proximity to the ground.

Apophis won’t come out unscathed

The researchers conducted a series numerical simulation try to understand exactly how the approach to our planet could affect the objects – particles, in fact – in orbit around Apophis. In the first case, taking into account only gravitational perturbations. In the second case, including perturbations due to pressure solar radiation. In just 24 hours within duration 30 years. With different density of objects in orbit.

It is concluded that the angleinfluence the number of asteroids is greater at a low density of objects in orbit (4°) than at a high density (2°). On the other hand, when the particle density decreases and the pressure solar radiation increases, these objects in orbit struggle to stay intact. And finally, in the low-density scenario of Apophis, about 90% of loose rocks on its surface will be removed when approaching the Earth. The researchers also show that Apophis’ approach could have minimal impact on the tides and produce some changes. landslides on the surface of the asteroid.

That astronomers now hope to use the passage of Apophis near our planet in 2029 to refine their model. And it is better to predict the consequences of the approach of asteroids in general in the future.

350-meter asteroid Apophis will not pose a threat in the next 100 years

New observations of the asteroid Apophis rule out any risk of a collision for at least a century. Thus, after 17 years of observations and analysis of the orbit, the asteroid was excluded from the list of potential impactors.

ArticleAdrian Coffine published on 04.05.2021

With a diameter of around 350 meters, the Apophis asteroid has regularly made headlines since its discovery in 2004 due to the low, but not zero, hazard it had.face with the Earth in the coming decades.

Shortly after its discovery, astronomers predicted two collision hazards: in 2029 as well as in 2036. Additional object observations NEO luckily ruled them out. However, until recently, there was little risk of a strike in 2068.

Impact excluded due to radar measurements

New radar observations of Apophis were passed at the beginning of March talk Goldstone Deep Space Communications Complex from NASA, California and Green Bank Observatory, West Virginia. They provided enough data on the asteroid’s orbit to definitively rule out any impact with Earth for at least 100 years.

These latest observations were made possible because on March 6 an asteroid passed close to Earth at a distance of about 17 million kilometers (44 times the Earth-Moon distance). Although the asteroid was still relatively far away, astronomers were able to accurately measure its distance and refine its orbit ahead of its next very close passage in 2029.

No passage through the “keyhole”

The positions and orbits of the planets are known very accurately, but for smaller objects such as asteroids, the uncertainty is often greater, especially when there are few observations yet. To complicate matters, when asteroids pass close to massive objects such as planets, they are deflected and the uncertainty about their path increases.

Until the latest radar measurements of Apophis, its orbit was known accurately enough to predict a series of safe approaches over the next few decades. The next and closest one will be on Friday, April 13, 2029, when Apophis will pass 38,000 kilometers from the center of the Earth (32,000 kilometers from its surface) and will be visibleeye naked. Then the asteroid will be ten times closer than mooncloser than geostationary satellites (at an altitude of 36,000 kilometers).

Davide Farnocchia from Center for the Study of Near-Earth Objects (CNEOS) NASA, explains that ” thanks to recent optical and radar observations, the uncertainty about the orbit of Apophis has been reduced from hundreds of kilometers to several kilometers as predicted for 2029. These radar observations reduced the uncertainty of Apophis’ trajectory to the point where any risk of a collision in 2068 or much later was eliminated.

As a result, Apophis was removed from List of ESA risk objects and from NASA.

The discovery of Apophis and the first work to track and understand its orbit occurred when today’s planetary defense activities were still in their infancy. ”, explains Juan Luis Cano of Near-Earth Object Coordination Center belonging’ESA.

The fact that this happened at such an early stage in the development of the discipline was a strong motivation for improving our ability to accurately predict the future. motion these interesting and potentially dangerous objects. With today’s removal of Apophis from the risk list, we close a very instructive chapter in the history of planetary defense. »

The trajectory of the large asteroid Apophis, which will collide with the Earth in 2029, has been changed.

Article Xavier Demeersmannpublished October 31, 2020

Everyone has heard or almost heard about Apophis, an asteroid the size of the Eiffel Tower that will hit Earth in 2029. Without the risk of collisions, as shown by the calculations of astronomers. But recent sightings are prompting researchers to reassess the risks of his visit in 2068.

Since astronomers discovered in 2004 that Apophis – (99942) Apophis – is a potentially dangerous asteroid that is expected to come close to Earth in 2029, 2036, 2068, 2085, 2088 according to their calculations, a celestial body with a diameter of about 340 meters became famous throughout the world. As for its passage at an altitude of about 31,860 kilometers above our heads on Friday April 13, 2029 (the date is undoubtedly related to its fame!) – we will be able to see the sky crossing with the naked eye – the researchers confirm that there is practically no risk of a collision with the Earth. So much the better, because if it rushed straight at us, it would cause significant damage on a regional scale. But, I repeat, NASA specialists are not afraid of either a collision or 2029neither in 2036 nor in 2068.

Although… for this last date, we will have to revise the projections.

illustration of asteroid Apophis. © ESA

Apophis “leaves a purely gravitational orbit”

During a meeting of the American Astronomical Society’s Department of Planetary Sciences just held virtually with the research community, Davide Farnocchia of Jet Propulsion Laboratory NASA unveiled its latest trajectory calculationsApophis, which take into account the recent discovery of a small Yarkovsky acceleration effect observed by colleagues at the Japanese Subaru Observatory in Hawaii. This effect, associated with thermal radiation, is very weak and almost imperceptible, but still enough to make scientists revise their copies.

“New Observations […] show that the asteroid is deviating from a purely gravitational orbit by about 170 meters per year, which is enough to keep the possibility of a collision in 2068.” said Dave Tolen of IfA (Institute of Astronomy) at the University of Hawaii, who made the observations.

However, there is no point in panicking, as the calculations need to be revised in the light of future observations of the behavior of the asteroid. Astronomers say we should know if Apophis will or will not be in the way of a collision with our world long before his visit in 2068. To be continued.

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