Dangerous Space
This is the text version of the interactive 3D documentary. 한국어
Danger ranking › Impact threats
Apophis
Impact threats · retired threat · Passes closer than geostationary satellites in 2029 — no impact risk for at least 100 years
View in 3D- Name
- 99942 Apophis
- Type
- Near-Earth asteroid
- Size
- About 340 m across
- Distance
- 38,042 km from Earth · light takes 0.13 s (Closest approach 13 April 2029 (21:50 UTC) · about 32,000 km above the surface · JPL Horizons)
The story in 3 scenes
Once the most dangerous asteroid
In June 2004, astronomers at Kitt Peak National Observatory in the US discovered an asteroid about 340 m wide. By that December, the calculated chance of it hitting Earth in 2029 briefly rose to 2.7%. It was given a 4 on the Torino scale — the highest rating ever assigned.
Why?Right after discovery, the observation period is short, so the range of possible orbits is wide. If Earth sits inside that range, the impact chance comes out high.
What nextAstronomers then found the asteroid in photos taken in March 2004. The extra data sharpened the orbit, and within days the 2029 impact was ruled out.
See this scene in 3D →The day it slips inside the satellite ring
On 13 April 2029, Apophis will pass about 32,000 km above Earth’s surface. That is closer than the geostationary orbit where TV and weather satellites circle (about 36,000 km up). An asteroid this big rarely comes this close, and it should be bright enough to see without a telescope.
Why?At this distance Earth’s gravity bends the asteroid’s path a lot. After the flyby, its orbit around the Sun will be different.
What nextNASA’s OSIRIS-APEX spacecraft plans to arrive just after the flyby and study how Earth’s pull shook its surface. The European Space Agency (ESA) is also preparing a mission called Ramses.
See this scene in 3D →No impact risk for 100 years
In March 2021, new radar measurements were used to recalculate the orbit. The result: no risk of hitting Earth for at least the next 100 years. Apophis was removed from NASA’s impact risk table.
Why?The last uncertainty was the Yarkovsky effect — the tiny push from heat leaving the sun-warmed surface. Over many years it can slowly shift an orbit.
What nextApophis went from “a dangerous asteroid” to “a chance to study one up close.”
See this scene in 3D →Sources
JPL Small-Body Database: 99942 · Wikipedia: 99942 Apophis
Impact-threat rankings and probabilities follow NASA/JPL’s Sentry risk table (as of 2026-11-04). The other categories are editorial rankings using the published criteria. Distances to stars can carry large uncertainties.