Key takeaways: asteroids that merit attention, not alarm
Concise, evidence-based answers for people asking whether an asteroid will hit Earth. Tracking programs monitor thousands of near-Earth objects (NEOs), and while impacts are inevitable over geologic time, significant impacts on human civilization are rare. A small number of asteroids merit routine monitoring, but none currently pose a significant threat of impact in the foreseeable future. Below you will find the most important definitions, currently tracked objects, impact likelihoods, detection and deflection methods, authoritative resources, and practical ways to stay informed.
What qualifies as a hazardous asteroid
Not every near-Earth asteroid can or will hit Earth. Scientists use specific definitions to separate interesting objects from genuine impact risks:
- Near-Earth object (NEO): any asteroid or comet whose orbit brings it within about 1.3 times the Earth–Sun distance (roughly 150 million km).
- Near-Earth asteroid (NEA): a rocky or metallic NEO; most tracked impact concerns apply to NEAs.
- Impact risk: calculated as the probability of impact multiplied by potential consequences; risk is expressed numerically using the Palermo Scale and simpler Torino Scale.
- Potentially hazardous asteroid (PHA): an NEA larger than ~140 m whose orbit comes within 0.05 AU (about 7.5 million km) of Earth’s orbit, warranting long-term monitoring.
Size matters: objects under ~25 m usually burn up harmlessly; civilization-relevant effects are associated with objects roughly 1 km and larger; regional damage can be caused by objects in the 50–130 m range.
Currently tracked asteroids and impact likelihoods
Major monitoring programs (notably NASA’s Center for Near-Earth Object Studies, ESA’s Near-Earth Objects Coordination Centre, and international partners) track thousands of NEOs. Most have effectively zero chance of hitting Earth in the next century. A handful warrant regular monitoring and occasional refinement of impact probabilities as new observations arrive. Decisions and alerts are coordinated through the International Asteroid Warning Network (IAWN) and, if needed, deflection missions are led by bodies such as ESA’s Space Situational Awareness Programme.
Notable tracked objects (overview)
Below is a concise reference summarizing the most frequently discussed objects and their current status. It is intended as an evergreen snapshot; probabilities are updated regularly as tracking improves.
| Asteroid (designation) | Estimated diameter | Closely approached Earth (date) | Current impact risk (1 in) | Notes and monitoring status |
|---|---|---|---|---|
| Apophis (99942) | ~340 m | 2029 Apr 13 (≈31,600 km) | Will pass within Earth’s geosynchronous zone in 2029; no significant impact risk for at least the next few decades. | |
| Bennu (101955) | ~490 m | 20 October 2024 (≈1.5 lunar distances) | ~1 in 1,750 cumulative through 2300 (peak ~2182) | Sample return mission OSIRIS-REx returned in 2023; refined tracking reduced concern while long-term impact probability remains very low. |
| 2006 QV89 | 20–50 m | 27 September 2019 (no impact) | Effectively zero now; was briefly monitored | Observations ruled out any near-term impact; removed from risk lists. |
| Duende (2012 DA14) | ~45 m | 15 Feb 2013 (≈27,700 km) | 0% (no current risk) | Well-observed; spurred global attention on undiscovered NEAs and planetary defense. |
| Chelyabinsk meteor (~2013) | ~18–20 m | 15 Feb 2013 (airburst) | N/A (already impacted) | Undetected before entry; regional damage and ~1,500 injuries demonstrated detection gaps for small objects. |
How impact probability is calculated and updated
When observations come in, scientists estimate orbital uncertainty. That uncertainty is propagated forward to compute the probability of Earth impact across many possible future trajectories (an impact scenario tree). Key points:
- Early observations yield wide uncertainty ellipses; probabilities can appear elevated until more observations pin down the orbit.
- Agencies such as NASA’s JPL and ESA’s NEOCC publish evolving risk pages; any notable change is accompanied by technical rationale and context.
- Statistical metrics: the Torino Scale communicates risk to the public (0–10), while the Palermo Scale expresses relative risk compared to background hazard.
- Updates typically occur as radar and optical tracking refine the orbit; many ‘threats’ disappear once the trajectory is better known.
Deflection technologies and preparedness measures
If a sufficiently large impactor were identified with enough lead time, humanity has candidate deflection technologies. To date, no asteroid has been demonstrably deflected by a spacecraft, but tests are underway:
- DART (NASA): successfully changed the orbital period of the asteroid moonlet Dimorphos in 2022, demonstrating kinetic impactor feasibility.
- Hera (ESA): planned to follow up and measure the resulting crater and momentum transfer in the Didymos system.
- Other concepts include gravity tractors, nuclear deflection, and focused-energy ablation, all requiring many years of lead time to be practical.
Preparedness also hinges on civil protection plans, international coordination through IAWN and national authorities, and public communication protocols to avoid misinformation during potential events.
Reliable resources and how to stay informed
To avoid sensationalism and access vetted updates, use authoritative sources that scientists and agencies rely on:
- NASA Planetary Defense: Planetary Defense Coordination Office (PDCO) and NEO Program Office.
- ESA Near-Earth Objects Coordination Centre and Space Situational Awareness Programme.
- International Asteroid Warning Network (IAWN) and UN-affiliated coordination groups.
- Minor Planet Center, JPL Small-Body Database, and monitored risk lists.
When an object generates headlines, check whether statements cite orbital uncertainties, Palermo/Torino scores, and how risk evolves with new data. True alerts cite credible models and avoid speculative timelines.
What this means for public concern and preparedness
Understanding the asteroid risk landscape yields a simple, durable conclusion: the vast majority of tracked asteroids pose no meaningful threat, and detection capabilities are improving. Nevertheless, no single-impact scenario can be ruled out entirely over long horizons, which is why planetary defense monitoring continues. By relying on vetted sources, understanding how uncertainties evolve, and recognizing the difference between media headlines and scientific assessments, people can remain informed without undue alarm.