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At a glance
- Width
- 27 to 59 m
- about 215 bananas
- Speed
- 8.86 km/s
- 31,907 km/h · 19,826 mph
- Misses us by
- 47.1 lunar
- 18,114,579 km · 11,255,874 miles
- First spotted by us
- 13th November 2026
- 5 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
- 1.14 Earth years (417 days)One lap of the Sun. Your commute is shorter, and so is your patience.
- Eccentricity
- 0.101How squashed the orbit is. 0 is a perfect circle, 1 is "leaving". This one is nearly circular and well behaved.
- Tilt
- 16.1°The angle of its orbit against the flat plane the planets share. Slightly tipsy.
- Closest to the Sun
- 0.98 AU147 million km. One AU is the distance from Earth to the Sun.
- Furthest from the Sun
- 1.20 AU180 million km. Never leaves the inner solar system.
- Closest orbit-to-orbit gap
- 0.039 AUIf you only compare the two orbits, not where the planets are, they come within 15 lunar distances. The rock is rarely there at the same time as us, which is the entire reason we are still here.
- Observations used
- 71NASA has measured this one 71 times. It has been stalked thoroughly.
- Watched for
- 13 days2019-04-27 to 2019-05-10. Not long, so the orbit is still being refined and the rock is still a bit of a stranger.
- Orbit uncertainty
- 7 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 |
|---|---|---|
| 23rd November 1977 | 162.3 LD · 62,434,934 km | 15.5 km/s |
| 13th May 1979 | 173.8 LD · 66,836,782 km | 17.2 km/s |
| 8th May 1987 | 123.2 LD · 47,393,271 km | 14.0 km/s |
| 5th May 1995 | 75.9 LD · 29,193,159 km | 11.3 km/s |
| 3rd May 2003 | 38.1 LD · 14,639,826 km | 9.6 km/s |
| 12th November 2010 | 44.8 LD · 17,231,319 km | 8.7 km/s |
| 2nd May 2011 | 18.9 LD · 7,260,832 km | 8.8 km/s |
| 14th November 2018 | 45.9 LD · 17,663,656 km | 8.8 km/s |
| 1st May 2019 | 15.9 LD · 6,119,550 km | 8.6 km/s |
| 15th November 2026 (this one) | 47.1 LD · 18,114,579 km | 8.9 km/s |
By the numbers
- Estimated mass
- 29,497 tonnes to 329,792 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
- 17 Olympic poolsSphere volume at the middle width estimate, divided by 2,500 cubic metres per Olympic pool.
- Impact energy, if it hit
- 277 kilotons to 3.1 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
- 0.8 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
- 0.30 timesDivided by Earth's own orbital speed of 29.78 km/s around the Sun.
- Time to cross the UK
- 109.4 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
- 23.7 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
- 60.4 secondsMiss distance divided by the speed of light.
- Width from brightness alone
- 27 to 59 mAstronomers estimate size from how bright an asteroid is (H 25.0) 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
- 0.013 days of observation divided by its 417-day year.
- Known close approaches, 1900 to 2200
- 270 inside the Moon's orbit and 0 within ten lunar distances.
- Closest pass in that period
- 14.71 lunar distancesOn 2nd May 2197.
- Next visit after this one
- 1st May 2027At 15.9 lunar distances. Closer than this time.
- Average gap between visits
- 10.3 yearsThe span of the record divided by the number of gaps between approaches.
- Rank by size
- 31 of 42Among every asteroid this site has tracked, biggest first.
- Rank by closeness
- 11 of 42Among every asteroid this site has tracked, using each one's most recent pass, closest first.
- Rank by speed
- 36 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 HW3 hit Earth? Questions answered
Will asteroid 2019 HW3 hit Earth?
No. 2019 HW3 passes Earth on 15th November 2026 at 47.1 lunar distances (18,114,579 km), which is 47.1 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 HW3?
NASA estimates it is between 27 m and 59 m wide, which at the top end is about 0.6 football pitches long. Nobody has seen it up close, so the width is an estimate from its brightness.
How fast is asteroid 2019 HW3 travelling?
8.9 km/s relative to Earth at closest approach, about 31,907 km/h (19,826 mph). That is 1.2 times the speed of the International Space Station.
Is 2019 HW3 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 HW3 has an absolute magnitude of 25.0 and its orbit comes within 0.039 AU of Earth's.
When is asteroid 2019 HW3's next close approach?
After this pass, the next one in NASA's record is on 15th November 2026, at 47.1 lunar distances.
Unhelpful facts
- 247 basketballs wide. Somebody in the NBA has already asked for the numbers.
- That is 660 times the speed limit on a 30 zone. Nobody has fined it yet.
- About 0.57 of a football pitch long. VAR would be unimpressed.
- As fast as 713 Usain Bolts at top speed, none of whom have been told.
- A snail would need 43,967 years to cover the gap. The snail would take the day off.
- About 169 wheels of Gouda across. A brave scientist would call that a dairy event.
- If this one did hit Earth, your next meeting would be cancelled. Look on the bright side.
- Misses by 47.1 times the distance to the Moon. The Moon has not filed a complaint.
- 167 large pizzas wide. Delivery in thirty minutes or it is free (it will not be free).
- In the 23.7 days it takes to fly a gap that size, you could drink 1,703 cups of tea. Most would go cold.
- It passes in 2 days, which is 14 dog days. Your dog is already nervous, mostly about the post.
- At its speed it covers a gap the size of its miss distance in 23.7 days. A group chat would still be picking a restaurant.