NASA Analysis: Earth Is Safe From Asteroid Apophis Impact for at Least 100 Years

Asteroid Apophis

Artist’s rendering of the asteroid Apophis approach to Earth.

The near-Earth object was thought to pose a slight risk of impacting Earth in 2068, but now radar observations have ruled that out.

Asteroid 99942 Apophis had been identified as one of the most hazardous asteroids that could impact Earth after its discovery in 2004. But that impact assessment changed as astronomers tracked Apophis and its orbit became better determined.

Now, the results from a new radar observation campaign combined with precise orbit analysis have helped astronomers conclude that there is no risk of Apophis impacting our planet for at least a century.

Estimated to be about 1,100 feet (340 meters) across, Apophis quickly gained notoriety as an asteroid that could pose a serious threat to Earth when astronomers predicted that it would come uncomfortably close in 2029. Thanks to additional observations of the near-Earth object (NEO), the risk of an impact in 2029 was later ruled out, as was the potential impact risk posed by another close approach in 2036. Until this month, however, a small chance of impact in 2068 still remained.

When Apophis made a distant flyby of Earth around March 5, astronomers took the opportunity to use powerful radar observations to refine the estimate of its orbit around the Sun with extreme precision, enabling them to confidently rule out any impact risk in 2068 and long after.

Asteroid Apophis Deep Space Network

These images of asteroid Apophis were recorded by radio antennas at the Deep Space Network’s Goldstone complex in California and the Green Bank Telescope in West Virginia. The asteroid was 10.6 million miles (17 million kilometers) away, and each pixel has a resolution of 127 feet (38.75 meters). Credit: NASA/JPL-Caltech and NSF/AUI/GBO

“A 2068 impact is not in the realm of possibility anymore, and our calculations don’t show any impact risk for at least the next 100 years,” said Davide Farnocchia of NASA’s Center for Near-Earth Object Studies (CNEOS), which is managed by NASA’s Jet Propulsion Laboratory in Southern California. “With the support of recent optical observations and additional radar observations, the uncertainty in Apophis’ orbit has collapsed from hundreds of kilometers to just a handful of kilometers when projected to 2029. This greatly improved knowledge of its position in 2029 provides more certainty of its future motion, so we can now remove Apophis from the risk list.”


This animation depicts the orbital trajectory of asteroid 99942 Apophis as it zooms safely past Earth on April 13, 2029. Earth’s gravity will slightly deflect the trajectory as the 1,100-foot-wide (340-meter-wide) near-Earth object comes within 20,000 miles (32,000 kilometers) of our planet’s surface. The dots are the many man-made satellites that orbit our planet. The motion has been speeded up 2,000 times. Credit: NASA/JPL-Caltech

Farnocchia was referring to the Sentry Impact Risk Table. Maintained by CNEOS, the table keeps tabs on the few asteroids whose orbits take them so close to Earth that an impact can’t be ruled out. With the recent findings, the Risk Table no longer includes Apophis.

Relying on optical telescopes and ground-based radar to help characterize every known near-Earth object’s orbit to improve long-term hazard assessments, CNEOS computes high-precision orbits in support of NASA’s Planetary Defense Coordination Office.

Science Opportunity

To arrive at the latest Apophis calculations, astronomers turned to the 70-meter (230-foot) radio antenna at the Deep Space Network’s Goldstone Deep Space Communications Complex near Barstow, California, to precisely track Apophis’ motion. “Although Apophis made a recent close approach with Earth, it was still nearly 10.6 million miles [17 million kilometers] away. Even so, we were able to acquire incredibly precise information about its distance to an accuracy of about 150 meters [490 feet],” said JPL scientist Marina Brozovic, who led the radar campaign. “This campaign not only helped us rule out any impact risk, it set us up for a wonderful science opportunity.”


This animation shows the path along Earth where Apophis will be visible on April 13, 2029. As the asteroid passes over the Atlantic ocean, its path briefly turns from red to grey – that is the moment of closest approach. After closest approach, the asteroid will move into the daytime sky and will no longer be visible. Credit: Marina Brozović/JPL

Goldstone also worked in a collaboration with the 100-meter (330-foot) Green Bank Telescope in West Virginia in order to enable imaging of Apophis; Goldstone was transmitting while Green Bank was receiving – a “bistatic” experiment that doubled the strength of the received signal.

Although the radar imagery of Apophis appears pixelated, the images have a resolution of 38.75 meters (127 feet) per pixel, “which is a remarkable resolution, considering the asteroid was 17 million kilometers away, or about 44 times the Earth-Moon distance,” added Brozovic. “If we had binoculars as powerful as this radar, we would be able to sit in Los Angeles and read a dinner menu at a restaurant in New York.”


This animation shows the distance between the Apophis asteroid and Earth at the time of the asteroid’s closest approach. The blue dots are the many man-made satellites that orbit our planet, and the pink represents the International Space Station. Credit: Marina Brozović/JPL

As the radar team further analyzes their data, they also hope to learn more about the asteroid’s shape. Previous radar observations have suggested that Apophis has a “bilobed,” or peanutlike, appearance. This is a relatively common shape among the near-Earth asteroids larger than 660 feet (200 meters) in diameter; at least one in six have two lobes.

Astronomers are also working to develop a better understanding of the asteroid’s rotation rate and the axis it spins around (known as its spin state). That knowledge will enable them to determine the orientation the asteroid will have with Earth as it encounters our planet’s gravitational field in 2029, which could change that spin state and even cause “asteroid quakes.”

On April 13, 2029, the asteroid Apophis will pass less than 20,000 miles (32,000 kilometers) from our planet’s surface – closer than the distance of geosynchronous satellites. During that 2029 close approach, Apophis will be visible to observers on the ground in the Eastern Hemisphere without the aid of a telescope or binoculars. It’s also an unprecedented opportunity for astronomers to get a close-up view of a solar system relic that is now just a scientific curiosity and not an immediate hazard to our planet.

“When I started working with asteroids after college, Apophis was the poster child for hazardous asteroids,” said Farnocchia. “There’s a certain sense of satisfaction to see it removed from the risk list, and we’re looking forward to the science we might uncover during its close approach in 2029.”

3 Comments on "NASA Analysis: Earth Is Safe From Asteroid Apophis Impact for at Least 100 Years"

  1. K.F. MacKellerann | March 27, 2021 at 11:41 am | Reply

    We have a century to deal with Apophis, but we probably won’t until it’s almost too late. Humans have two weaknesses (among many) that will bring this about. One: If it is not “Shiny” we tend to ignore things, and Two: We always have something “more important” to get involved with when we face a potential, if distant, threat. Will Apophis hit Earth? “Maybe it will, maybe it won’t”. <<<And THAT is why we won't do anything about it until it is almost too late.

  2. … and that is just an example how we are weak at understanding stuff.
    The first of all, that would be correct in the case that we live in a system that works like a watch, it perfect till some time there is an error so small.
    But, we live in a way more complex system, very small changes in the path can do a significant change in a path, and there you go.
    It is not just stuff from our system, some rogue planet can swirl in too…

  3. dr mehrdad kesiri | December 6, 2023 at 7:03 am | Reply

    The Nature of the Gods of the Earth Chapter 1 Perhaps I am the first person in Iran, I am talking about the nature of the Gods of the Earth.During the past few decades, I asked the clerics about the structure and nature of God, and they said that God, God, is not a visible Lord and has not appeared to anyone No one can see him and no God has spoken directly to hisprophets.I was seventeen years old at that time and I had read the books of constellations and galaxies and the stars of the sky and the planets of the solar system and I had read the book Physics of Astronomy and the Structure of the Atom written by Albert Einstein.Those books were the first books that I had read 42 years ago.When someone has information about astronomy and general information, his mind opens up about knowing the world around him and about religious and belief issues.I remember after I read the book I mentioned.I had read it completely.I was arguing with my older brother who was religious.I said that God does not exist.It is possible that he himself created the stars.I told my brother that I read in the holy books that the Father, the Son, and the Holy Spirit said to his prophet, “We breathed our own spirit on you, and you are one of the mysteries.”You have become aware of the occult world and its science, I said, therefore, it is the soul itself, and the soul burns at millions of temperatures, etc. It is possible that it could have created the sun.Why is it that God has always used the word we and the plural verb in all holy books, not the singular verb that is I, so that God is not one, so how can we accept the words of Islamic mullahs, mullahs and clerics,they say that God is one and is one and doesn’t have a partner, isn’t our word a plural verb?I asked most of the clerics this question, but they couldn’t give me a convincing answer.We Iranians have a proverb, they say that the seeker is the finder.The meaning of the finder is that a person thinks about something, the Gods of that person’s people find the truth with inspiration and Revelation makes it manifest and visible to him.This is how I realized the nature of the Gods when I saw the souls of the great prophets of my people, Muhammad, the Messenger of God, Farba Forohar, and Jesus Christ in a curtain that dates back to the Sassanid era of Cyrus, whichwas the year 2570, and to It was the year 2010 and it was the lunar year 1432. I saw that most of the world’s prophets appeared to me in four scenes.After 13 years when they appeared in a cream-colored curtain by the gods of the earth, I realized that the prophets that God and the world’s lords appeared to me in the curtain.Oh, they appeared, it is not their real soul that all those prophets were gathered in a curtain at the same time.Is it possible that the souls of those whose corpses were buried in the ground thousands of kilometers away in different places of the world can be seen in one curtain?Look, I said that we Iranians have a proverb, we say that there is a seeker, there is a finder, what does that mean?This example means that whatever a person thinks, his God will reveal the truth to him, and I understood that after thirteen years that have passed since the time that I explained, three prophets of the Gods of the earth appeared to me, but I after13 years of those scenes of the appearance of the prophets I thought in that curtain, now I understand that it was the gods of the earth who showed me the image of those dear prophets.This topic continues in the next comments, I will talk about this very, very important topic, Dr.tejrobi mehrdad kesiri but aghakesiri time in iran 6:33 . pm

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