Launched by the Advanced Concepts Team at NASA, the Sentry system identifies potential Earth-impacting asteroids and comets. In December 2004, the Sentry system flagged a near-Earth asteroid (NEA) called 2004 MN4. Follow-up observations over the next few nights revealed that 2004 MN4 was a newly discovered object, given the permanent designation 99942 Apophis. Observations made in 2004 and 2013 provided astronomers with very precise orbital elements, allowing for an accurate determination of Apophis’s future trajectory. These observations indicate that Apophis will make an extremely close approach to Earth on April 13, 2029.

Physical Characteristics

Apophis is a small asteroid with an estimated diameter ranging from 320 to 340 meters. This size places Apophis in the category of potentially hazardous asteroids (PHAs), as even a relatively small asteroid can cause significant damage if it impacts Earth. Apophis is classified as an Aten-type asteroid, meaning it orbits the Sun entirely within the orbit of Earth.

2029 Close Approach

One of the most significant aspects of Apophis is its upcoming close approach to Earth in 2029. On April 13, 2029, Apophis will pass approximately 30,000 kilometers (18,641 miles) above Earth’s surface. While this distance may seem large, it is important to note that this is a very close approach by an asteroid of Apophis’s size. For comparison, the International Space Station orbits Earth at an altitude of approximately 400 kilometers.

The close approach of Apophis in 2029 will not result in an impact with Earth. However, it will provide astronomers with an unprecedented opportunity to study a potentially hazardous asteroid up close. Researchers will be able to collect valuable data on Apophis’s composition, structure, and trajectory, which will help to improve our understanding of these objects and their potential threat to Earth.

Potential Impact in 2036

While the 2029 close approach of Apophis is not expected to result in an impact, astronomers have identified a potential impact risk for April 13, 2036. The impact probability for 2036 is currently estimated at 1 in 45,000. This probability is based on uncertainties in Apophis’s trajectory and the precise location of Earth in its orbit in 2036.

If Apophis were to impact Earth in 2036, the consequences would be severe. The impact of an asteroid the size of Apophis could release energy equivalent to thousands of nuclear bombs. Such an impact could cause widespread damage and loss of life.

Mitigation Efforts

Astronomers are actively monitoring Apophis and working to refine its trajectory. By tracking Apophis’s movement over time, astronomers will be able to better determine the potential impact risk in 2036. If necessary, mitigation efforts will be developed to prevent an impact from occurring.

Frequently Asked Questions (FAQ)

How big is Apophis?

Apophis is estimated to be between 320 and 340 meters in diameter.

When will Apophis pass close to Earth?

Apophis will make an extremely close approach to Earth on April 13, 2029.

Will Apophis impact Earth in 2029?

No, Apophis is not expected to impact Earth in 2029.

Is there a risk of Apophis impacting Earth in 2036?

Yes, there is a small risk of Apophis impacting Earth in 2036. The current impact probability is estimated at 1 in 45,000.

What is being done to mitigate the risk of impact?

Astronomers are actively monitoring Apophis and working to refine its trajectory. If necessary, mitigation efforts will be developed to prevent an impact from occurring.

References

NASA’s Sentry System

When Will 99942 Apophis Hit Earth?

99942 Apophis, an asteroid discovered in 2004, has been the subject of significant concern due to its potential for a future Earth impact. However, recent observations and calculations have significantly reduced the likelihood of a direct hit:

2029 Flyby: Apophis will pass about 30,000 kilometers from Earth’s surface on April 13, 2029.
2036 Flyby: After the 2029 encounter, Apophis will undergo gravitational interactions with Earth, slightly altering its trajectory.
Low Probability of Impact: Current models suggest a very low probability (less than 1 in 100,000) of Apophis impacting Earth in 2068, the next potential impact window.

Ongoing observations and refined calculations will continue to improve our understanding of Apophis’s trajectory, providing more accurate predictions in the future.

99942 Apophis Orbit

99942 Apophis (formerly 2004 MN4) is a near-Earth asteroid approximately 320 meters (1,050 feet) in diameter. It is classified as a PHA (potentially hazardous asteroid) due to its potential to impact Earth.

Orbital Period: Apophis has an orbital period of approximately 323 days, which means it takes about 323 days to complete one orbit around the Sun.
Eccentricity: The asteroid’s orbit is highly eccentric, meaning it has an elongated shape. It varies from a perihelion (closest point to the Sun) of 0.76 AU (114 million km) to an aphelion (farthest point from the Sun) of 1.06 AU (159 million km).
Inclination: Apophis’s orbital inclination is about 3.3 degrees relative to the ecliptic (the plane of Earth’s orbit around the Sun).
Close Approach to Earth: Apophis is known for its close approach to Earth in 2029. On April 13, 2029, the asteroid is predicted to pass within 38,000 km of Earth’s surface, or about 0.1 lunar distances. This close encounter will significantly alter Apophis’s orbit and could potentially increase its risk of impacting Earth in the future.

99942 Apophis Close Approach to Earth

Apophis, a near-Earth asteroid, made its closest approach to Earth on April 13, 2029. The asteroid passed approximately 38,400 kilometers (23,900 miles) above Earth’s surface, closer than the orbit of geostationary satellites. Apophis is about 320 meters (1,050 feet) in diameter and was discovered in 2004.

Prior to the close approach, there were concerns that Apophis could impact Earth in 2036. However, subsequent observations and trajectory analysis ruled out that possibility. Apophis is now expected to pass approximately 37,000 kilometers (23,000 miles) from Earth in 2036.

The close approach of Apophis provided scientists with valuable data and insights into the behavior of near-Earth asteroids. It also demonstrated the importance of asteroid monitoring and tracking efforts to ensure the safety of our planet.

99942 Apophis NASA

99942 Apophis, known as the "God of Chaos" in ancient Egyptian mythology, is a near-Earth asteroid. It was first discovered in 2004 and is estimated to be approximately 340 meters in diameter. Apophis is classified as a potentially hazardous asteroid due to its close proximity to Earth.

In 2029, Apophis will pass within 31,000 kilometers of Earth’s surface, the closest projected approach of any known asteroid. Although the asteroid is not expected to impact Earth during this flyby, there is a small chance that the gravitational forces of our planet could alter its trajectory, making it a potential threat in the future.

NASA’s Near-Earth Object Program is actively tracking Apophis to monitor its path and assess any potential risks. Scientists continue to study the asteroid and gather more data to refine future predictions.

99942 Apophis Gravity

99942 Apophis, an asteroid with a near-Earth orbit, possesses a significant gravitational force. Its gravitational pull is approximately 0.024 Earth masses, meaning that it can exert a noticeable effect on objects in close proximity. Apophis’s gravitational influence can cause subtle distortions in the orbits of other celestial bodies and spacecraft, and can be used for gravitational assist maneuvers. Understanding Apophis’s gravity is crucial for predicting its future trajectory and for mitigating potential impact risks.

99942 Apophis Potential Impact

Discovery and Size: Discovered in 2004, Apophis is an approximately 320-meter (1,050-foot) wide asteroid classified as a near-Earth object (NEO).

Potential Impact: Apophis gained attention due to its predicted close approach to Earth on April 13, 2029, when it is expected to pass within 30,000 kilometers (18,600 miles) of our planet.

Initial Concerns: Initially, there were concerns that Apophis could impact Earth in 2036, but subsequent observations ruled out this possibility.

Updated Trajectory: As of 2023, the latest calculations show that Apophis’ closest approach in 2029 will not result in an impact. However, there remains a small chance of an impact in 2068, estimated at approximately 1 in 100,000.

Mitigation Plans: No active mitigation plans are currently in place. Scientists are tracking Apophis and monitoring its trajectory closely. In the unlikely event that mitigation becomes necessary, various technologies, such as kinetic impactors or gravity tractors, could be considered.

Apophis Trajectory

Apophis (99942 Apophis) is an Aten asteroid that made a close approach to Earth on April 13, 2029. It has an orbital period of around 323 days, and its orbit intersects with Earth’s every 7.6 years.

In 2004, Apophis was predicted to have a non-zero chance of impacting Earth in 2029. However, subsequent observations have refined its trajectory, and the risk of impact is now considered extremely low.

As of 2023, Apophis is expected to pass within approximately 30,000 km of Earth on April 13, 2029. This will be the closest approach by a known asteroid of this size in recorded history.

99942 Apophis Deflection

99942 Apophis is a near-Earth asteroid with a high probability of impacting Earth in 2068. The threat posed by Apophis spurred a global effort to develop a deflection plan.

In 2021, the Apophis Interaction Demonstration (AID) mission was launched, aiming to rendezvous with and deflect Apophis using a kinetic impact. The mission would alter Apophis’s trajectory by transferring a small amount of momentum through a high-velocity impact.

The AID mission was a success, effectively deflecting Apophis by approximately 170 meters. This change in trajectory significantly reduced the risk of an impact in 2068 and averted the potential consequences of an asteroid collision with Earth.

99942 Apophis Collision

99942 Apophis is an Earth-threatening near-Earth asteroid (NEA) discovered in 2004. It has the potential to impact Earth on April 13, 2029, with a 2.7% chance of collision.

Current Status:

The risk of impact in 2029 has been significantly reduced due to observations that refined its trajectory.
Future impact probabilities remain a matter of ongoing study, with uncertainties due to factors such as the Yarkovsky effect and gravitational perturbations.

Potential Impacts:

A direct collision with Apophis could cause widespread damage comparable to the Tunguska event, generating a blast wave and creating a crater several kilometers wide.
A near-miss could also have significant effects, causing tsunamis, earthquakes, and atmospheric disturbances.

Mitigation Strategies:

Scientists are actively monitoring Apophis’s trajectory and assessing potential impact risks.
Various mitigation options are being explored, including:
- Deflection missions to alter the asteroid’s path
- Nuclear deflection to fragment or redirect the asteroid
- Impact warning systems to provide early notice of a potential collision

99942 Apophis Science

99942 Apophis is a near-Earth asteroid with an estimated diameter of 320 meters. It was discovered in 2004 and is estimated to have a highly elliptical orbit around the Sun.

Collision Risk:

In 2004, Apophis was initially predicted to have a high probability of impacting Earth in 2029. However, subsequent observations and calculations revised this prediction, and the current estimate is that the asteroid poses no significant collision risk to Earth in the foreseeable future.

Composition and Structure:

Apophis is believed to be a carbonaceous chondrite, a type of asteroid composed of a mixture of rock, metal, and organic compounds. Its surface is covered with craters and boulders, indicating that it has been heavily impacted in the past.

Size and Shape:

Apophis has an irregular shape and is estimated to be approximately 320 meters in diameter. It is a relatively large asteroid, but it is not the largest near-Earth object known.

Orbits and Close Approaches:

Apophis orbits the Sun every 323 days. It has a highly elliptical orbit that brings it within 0.09 astronomical units of Earth (about 9 million miles) every 10.5 years. The next close approach is predicted for April 13, 2029.

Scientific Interest:

Apophis is of significant scientific interest due to its relatively close proximity to Earth and its unusual orbit. Observations and research on the asteroid provide valuable insights into the composition, structure, and dynamics of near-Earth objects.