What if an asteroid hit Earth? Asteroid Apophis, about 340 metres across, will fly past Earth on Friday 13 April 2029, closer than many satellites.
It will safely miss us: NASA says there is no risk of it hitting Earth for at least 100 years. In 2004, for a few days, it looked like it might. So we ask what would happen if it did: the warning, the last seconds, the impact, and whether we could push it away.
0:00 Friday 13 April 2029
0:50 The 2004 scare
2:04 How much warning would we get?
3:02 The last seconds
4:21 The impact
5:49 Would it end the world?
6:40 Could we push it away? (DART)
7:54 What will really happen in 2029
What this film does and does not claim: the impact is a made-up scenario, labelled on screen. Its numbers are estimates for a stony 340 m asteroid at about 12.6 km/s: roughly 1,000 megatons of TNT (our own kinetic-energy calculation) and a crater about 5 km wide on solid ground (Collins, Melosh & Marcus 2005 scaling). Real effects would depend on where and how it hit. Ocean impacts and their waves are still debated. No real close-up photo of Apophis exists: the 2021 radar images are real data; the tumbling asteroid is NASA's artist's concept, and the flyby shots are NASA visualisations, all labelled on screen.
Sources
- NASA/JPL Center for Near Earth Object Studies (Sentry); NASA, "NASA Analysis: Earth Is Safe From Asteroid Apophis for 100-Plus Years" (March 2021)
- NASA/JPL, Apophis radar observations, Goldstone and Green Bank (March 2021)
- Chesley (2005) and NASA/JPL news on the December 2004 Torino scale 4 rating and 1-in-37 estimate
- Daly et al. and Thomas et al., Nature (2023), the DART impact and orbit change; NASA, DART orbit-change results (33 minutes, 2022)
- Popova et al., Science (2013), the Chelyabinsk airburst; NASA Goddard, Chelyabinsk plume (Gorkavyi et al. 2013)
- Collins, Melosh & Marcus, Meteoritics & Planetary Science (2005), Earth Impact Effects Program
- Kring, Guidebook to the Geology of Barringer Meteorite Crater (2007); Tunguska: Kulik expedition records; Chicxulub: NASA/JPL SRTM (PIA03379)
- NASA OSIRIS-APEX mission pages; ESA Ramses mission pages; NASA NEO Surveyor mission pages
Visuals: NASA, JPL-Caltech, Goddard Space Flight Center (Scientific Visualization Studio and Conceptual Image Lab), Johnson Space Center, Johns Hopkins APL, University of Arizona, NSF/AUI/GBO, NASA Earth Observatory/NOAA, USGS/D. Roddy; Tunguska photo by the 1929 Kulik expedition (public domain). Hubble images: NASA, ESA, J. Li (PSI), J. DePasquale (STScI), CC BY 4.0. Thumbnail: a real space-station photo of Earth with NASA's artist's concept of Apophis added; it is a composite, not a real photo. Music, sound effects and cards are original.
Narration is a synthetic voice. Independent production, not affiliated with or endorsed by NASA.
If you could be anywhere on Earth on the night of 13 April 2029, where would you watch Apophis from? Tell us in the comments.
