At a glance
- Width
- 146 to 327 m
- about 1,181 bananas
- Speed
- 22.07 km/s
- 79,447 km/h · 49,366 mph
- Misses us by
- 55.2 lunar
- 21,212,582 km · 13,180,883 miles
- First spotted by us
- 13th November 2026
- 3 page views
How far is "close"?
Same gap, ranked against places you have heard of, on a log scale because the Sun is awkwardly far away.
How big is it, really?
NASA only estimates the width, so we show the biggest guess. Log scale again. Everest is just there to make everything else look reasonable.
How fast is it going?
Speed relative to Earth at closest approach. The International Space Station is the fastest thing most of us will ever stand under. This lot would lap it.
If it hit (it will not)
Rough impact energy at the biggest size estimate, assuming solid rock, in tonnes, kilotons and megatons of TNT, which is how everyone who has to do this maths measures it. Treat it as a ballpark. The point stands: no impact is scheduled.
Where it actually lives
A top-down view of the orbit, to scale, with Earth's and Mars's orbits for company. The tilt of the orbit is ignored, so treat the shape as right and the exact position as roughly right. The Sun is the orange dot in the middle.
- Orbit class
- APOApollo: crosses Earth's orbit, but spends most of its time further out than us. The most common troublemaker type.
- Year length
- 1.41 Earth years (517 days)One lap of the Sun. Your commute is shorter, and so is your patience.
- Eccentricity
- 0.309How squashed the orbit is. 0 is a perfect circle, 1 is "leaving". Noticeably oval. Mildly dramatic.
- Tilt
- 38.0°The angle of its orbit against the flat plane the planets share. Properly tilted. It mostly visits from above or below.
- Closest to the Sun
- 0.87 AU130 million km. One AU is the distance from Earth to the Sun.
- Furthest from the Sun
- 1.65 AU247 million km. Out past Mars.
- Closest orbit-to-orbit gap
- 0.120 AUIf you only compare the two orbits, not where the planets are, they come within 47 lunar distances. The rock is rarely there at the same time as us, which is the entire reason we are still here.
- Observations used
- 172NASA has measured this one 172 times. It has been stalked thoroughly.
- Watched for
- 7.0 years2019-04-27 to 2026-04-22. Not long, so the orbit is still being refined and the rock is still a bit of a stranger.
- Orbit uncertainty
- 0 out of 90 means we know exactly where it is going. 9 means a shrug. Lower is better.
Is it actually hazardous?
This one fails at least one test, so it is not on the list. It is comfortably, boringly harmless.
Not on NASA's Sentry impact-risk watch list. No further action, no thoughts, head empty.
Its history with us
Every known pass this rock makes, 1900 to 2200. Dim dots are the past, green dots are still to come, the big orange ring is this one. The dashed line is the Moon's distance, so anything below it is closer than the Moon. Almost nothing is.
| Date | Miss distance | Speed |
|---|---|---|
| 22nd May 1903 | 47.7 LD · 18,327,242 km | 20.6 km/s |
| 13th November 1910 | 51.0 LD · 19,630,483 km | 20.7 km/s |
| 18th May 1920 | 59.9 LD · 23,030,259 km | 22.1 km/s |
| 17th November 1951 | 71.4 LD · 27,462,179 km | 23.1 km/s |
| 22nd May 1961 | 54.0 LD · 20,776,384 km | 20.0 km/s |
| 14th November 1968 | 49.0 LD · 18,838,176 km | 21.3 km/s |
| 20th May 1978 | 50.5 LD · 19,434,623 km | 21.4 km/s |
| 12th November 1985 | 64.6 LD · 24,829,310 km | 20.0 km/s |
| 24th May 2019 | 67.8 LD · 26,086,400 km | 19.5 km/s |
| 16th November 2026 (this one) | 55.2 LD · 21,212,582 km | 22.1 km/s |
By the numbers
- Estimated mass
- 4.9 million tonnes to 54.7 million tonnesVolume of a sphere at NASA's smallest and largest width estimates, times 3,000 kg per cubic metre (typical rock). Real shapes are lumpier, so treat it as a ballpark.
- Swimming pools of rock
- 2,765 Olympic poolsSphere volume at the middle width estimate, divided by 2,500 cubic metres per Olympic pool.
- Impact energy, if it hit
- 285 megatons to 3,185 megatonsHalf mass times speed squared, at the small and large width estimates, converted to TNT (1 kiloton is 4.184 trillion joules). A rock this far away is not going to do this.
- Speed against escape velocity
- 2.0 timesIts speed relative to Earth, divided by the 11.186 km/s needed to leave Earth's gravity. It is travelling a lot faster than we can throw things.
- Speed against Earth in orbit
- 0.74 timesDivided by Earth's own orbital speed of 29.78 km/s around the Sun.
- Time to cross the UK
- 44.0 secondsLand's End to John o' Groats is about 970 km in a straight line. Divided by its speed.
- Time to fly the miss distance
- 11.1 daysThe miss distance divided by its speed. This is how long it needs to cover a gap of that size, which is a measure of how near or far the pass is.
- Light takes to cross the gap
- 70.8 secondsMiss distance divided by the speed of light.
- Width from brightness alone
- 146 to 327 mAstronomers estimate size from how bright an asteroid is (H 21.3) and how reflective it is. A shiny rock (albedo 0.25) is smaller than a dark one (0.05) for the same brightness. NASA's own estimate above uses the same idea.
- Laps of the Sun since first spotted
- 4.92,552 days of observation divided by its 517-day year.
- Known close approaches, 1900 to 2200
- 230 inside the Moon's orbit and 0 within ten lunar distances.
- Closest pass in that period
- 47.46 lunar distancesOn 21st May 2036.
- Next visit after this one
- 21st May 2036At 47.5 lunar distances. Closer than this time.
- Average gap between visits
- 12.9 yearsThe span of the record divided by the number of gaps between approaches.
- Rank by size
- 12 of 42Among every asteroid this site has tracked, biggest first.
- Rank by closeness
- 14 of 42Among every asteroid this site has tracked, using each one's most recent pass, closest first.
- Rank by speed
- 4 of 42Among every asteroid this site has tracked, fastest first.
How reliable are these?
Width, speed, miss distance and orbit come straight from NASA. Mass, energy, volume and the rankings are our own arithmetic on top, and the assumptions are written beside each one. NASA publishes a range for width because nobody has seen most of these rocks up close, so wherever we show one number it uses the biggest estimate and says so.
Will asteroid 2019 HK4 hit Earth? Questions answered
Will asteroid 2019 HK4 hit Earth?
No. 2019 HK4 passes Earth on 16th November 2026 at 55.2 lunar distances (21,212,582 km), which is 55.2 times the distance to the Moon. It is not on NASA's potentially hazardous list. It is not on NASA's Sentry impact-risk watch list.
How big is asteroid 2019 HK4?
NASA estimates it is between 146 m and 327 m wide, which at the top end is about 3.1 football pitches long. Nobody has seen it up close, so the width is an estimate from its brightness.
How fast is asteroid 2019 HK4 travelling?
22.1 km/s relative to Earth at closest approach, about 79,447 km/h (49,366 mph). That is 2.9 times the speed of the International Space Station.
Is 2019 HK4 a potentially hazardous asteroid?
No. NASA gives the label to asteroids whose orbit comes within 0.05 astronomical units of Earth's (about 7.5 million km) and which are bigger than roughly 140 m. 2019 HK4 has an absolute magnitude of 21.3 and its orbit comes within 0.120 AU of Earth's.
When is asteroid 2019 HK4's next close approach?
After this pass, the next one in NASA's record is on 16th November 2026, at 55.2 lunar distances.
Unhelpful facts
- At its speed it covers a gap the size of its miss distance in 11.1 days. A group chat would still be picking a restaurant.
- Roughly 502 car tyres wide. Check the tread before you worry about the rock.
- If it did hit, that would release roughly 3,185 megatons of TNT, assuming solid rock. It will not, so enjoy the number.
- It passes in 3 days, which is 21 dog days. Your dog is already nervous, mostly about the post.
- Flying a gap that size takes it 11.1 days, which is 801 twenty-minute naps. Recommended.
- About 3.1 football pitches long. Still no better than a mid-table side.
- A jet would have to circle Earth 529 times to cover the gap. Baggage still lost.
- 918 large pizzas wide. Delivery in thirty minutes or it is free (it will not be free).
- It is moving 226 times faster than a sports car, and has never once paid a congestion charge.
- At this speed it covers the distance to the Moon in 4.8 hours. Your train replacement bus takes longer.
- Line up 54 elephants to match its width. The elephants would like to be consulted first.
- A snail would need 51,487 years to cover the gap. The snail would take the day off.