Asteroid 99942

Apophis - the
2029 flyby

When Apophis was discovered in 2004, it briefly carried the highest impact probability ever recorded for a known asteroid. Twenty years later, we know it will miss - and fly close enough to watch with the naked eye.

Watch the 2029 flyby in 3D Full 2029 event guide →

Diameter

~370 m

Roughly the height of The Shard

2029 flyby distance

~38,000 km

From Earth's centre (13 April 2029)

Peak brightness

Magnitude ~3.1

Visible to the naked eye

Impact risk (2029)

Zero

Confirmed by 2021 radar observations

Discovery and the initial alarm

Apophis was first observed on 19 June 2004 at Kitt Peak National Observatory in Arizona. Initial orbital calculations, based on limited data, suggested a 2.7% probability of impact with Earth on 13 April 2029 - an unprecedented finding that briefly elevated the asteroid to Torino Scale 4, the highest rating ever assigned to a real object.

The alarm was short-lived. Additional observations over the following weeks, combined with archival images that pinned down the orbit more precisely, refined the trajectory. By early January 2005, the 2029 impact had been ruled out. Apophis was downgraded to Torino Scale 1, then 0.

Attention shifted to 2036 and 2068 as possible impact dates. For several years, Apophis remained on NASA's risk table. In March 2021, radar observations during a close approach allowed a highly precise orbital solution. The updated data ruled out any impact through at least 2068 with high confidence, and Apophis was removed from the risk table entirely.

The 2029 flyby - what to expect

Apophis will make its closest approach to Earth at approximately 21:46 UTC on 13 April 2029 - a Friday evening local time across much of Europe. At that moment, it will be approximately 38,000 km from Earth's centre, or roughly 32,000 km from the surface. That is closer than the geostationary satellite belt, which sits at around 35,786 km from Earth's centre.

From the right location - Europe, Africa, western Asia - Apophis will be visible without optical aid, moving noticeably against the star background over the course of the night. It will reach an estimated peak brightness of around magnitude 3.1, similar to a moderately bright star in a dark sky.

The pass will last several hours in terms of naked-eye visibility, after which Apophis will fade as it moves away. The entire flyby geometry means it will be poorly placed for observers in the Americas during peak brightness.

A scientific opportunity

The 2029 flyby offers a rare opportunity to study a large near-Earth asteroid at close range without a long interplanetary mission. Ground-based radar, optical, and infrared telescopes will collect more data on Apophis in a matter of hours than most asteroids receive in decades.

ESA's proposed Ramses mission aims to rendezvous with Apophis before the flyby and accompany it through the encounter, studying how Earth's tidal forces affect the asteroid's surface and interior. The flyby will also subtly alter Apophis's orbit. Tracking those changes with precision will help refine long-term probability calculations for its future encounters with Earth.

The Apophis 2029 event guide

How to observe it, what missions are planned, and what happens next.

Famous close approaches

Historical context - from Tunguska to DART.

Record close passes

Where Apophis 2029 ranks in the all-time flyby table.

The Torino Scale

How Apophis reached Torino 4 - and why it is now at 0.

Common questions

What is the Apophis asteroid?

99942 Apophis is a near-Earth asteroid approximately 370 metres across. It was discovered on 19 June 2004 by astronomers Roy Tucker, David Tholen, and Fabrizio Bernardi at Kitt Peak National Observatory. Initial orbital calculations suggested a significant chance of impact with Earth in 2029 - the highest impact probability ever recorded for a known asteroid. Subsequent observations refined the orbit and ruled out the 2029 impact. Apophis will instead pass at roughly 38,000 km from Earth's centre that year.

Will Apophis hit Earth in 2029?

No. Radar observations in 2021 refined the orbit with high precision and confirmed that Apophis will miss Earth in 2029. The pass will occur at approximately 38,000 km from Earth's centre - close enough to be visible to the naked eye, but with no impact risk. NASA and ESA have independently confirmed this finding.

How close will Apophis come in 2029?

Apophis will pass at approximately 38,000 km from Earth's centre on 13 April 2029. Earth's radius is about 6,371 km, placing the flyby at roughly 32,000 km from the surface. This is closer than geostationary satellites, which orbit at 35,786 km from Earth's centre. It is the closest known approach by an asteroid of this size in recorded history.

Can I see Apophis with the naked eye in 2029?

Yes, from the right location. Apophis will be visible to the naked eye over a wide area including Europe, Africa, and western Asia on the evening of 13 April 2029. Moving visibly against the star background, it will reach an estimated maximum brightness of magnitude 3.1 - comparable to a moderately bright star. The exact visibility window depends on your location.

What happens after the 2029 flyby?

Earth's gravity will slightly alter Apophis's orbit during the 2029 flyby. The precise post-flyby orbit will determine the probability of closer future encounters - particularly a 2036 pass and a 2068 pass. Radar and optical observations during and after the 2029 flyby will pin down the post-flyby orbit with high precision. Current models suggest the 2036 and 2068 encounters carry essentially zero impact probability, but that assessment will be refined with 2029 flyby data.

Will any spacecraft visit Apophis in 2029?

Yes. Several missions are planned or under consideration. JAXA's DESTINY+ mission was originally targeting another asteroid but the Apophis encounter has been discussed in mission planning circles. ESA's Ramses mission and NASA have expressed interest in observing Apophis at close range during the 2029 flyby. The encounter presents a rare opportunity to study a large near-Earth asteroid in situ without a long interplanetary cruise.