1950 DA
Key facts
- What it is
- Near-Earth asteroid (Apollo group)
- Size
- About 1.3 km across
- Discovered
- 1950, by Carl Wirtanen
- Spacecraft
- Not yet visited
- Orbit group
- Apollo
- Average distance from the Sun
- 1.7 au (about 250 million km)
- Time to go round the Sun
- 2.2 years
- Closest and farthest from the Sun
- 0.84 to 2.56 au
- Tilt of its orbit
- 12.2°
- Closest its orbit comes to Earth's
- 5,900,000 km (15 times the Moon's distance)
- Spins once every
- 2.1 hours
An au (astronomical unit) is Earth's average distance from the Sun, about 150 million km. Orbit figures are from open tracking data, figures last updated 1 Nov 2026.
1950 DA is an asteroid about 1.3 kilometres across whose orbit is being watched with great patience, because the date of interest is more than eight centuries away. In March of the year 2880 it will pass close to Earth, and calculations give a small chance, at most a few in ten thousand, that it could hit.
Carl Wirtanen discovered it at the Lick Observatory in California on 23 February 1950. It was followed for only 17 days and then lost, because its orbit was not known well enough to say where it would be later. On the last day of 2000 a survey telescope found an object that turned out to be the same asteroid, and its long-lost early observations helped pin down its path.
Predicting an orbit so far ahead is unusually hard. The biggest uncertainty is the Yarkovsky effect: the tiny push an asteroid gets from giving off the heat it absorbs from sunlight. Over centuries, this small push adds up, and its size depends on the asteroid's shape, spin, surface and direction of rotation. Radar and telescope studies have measured these properties to narrow the range.
1950 DA spins once every two hours and seven minutes, so fast that loose rubble on its surface would fly off unless something else held it in place. Scientists think weak cohesive forces between grains, similar to the clumping of fine powder, keep it together.
With over 850 years to go, there is ample time to refine the orbit and, if it were ever needed, to change it. Very likely the chance will drop to zero as tracking continues.
Coming close to Earth
Its next passes within about 30 million km of Earth, worked out from its orbit. Each one is a safe miss.
| Date | Distance | In Moon distances |
|---|---|---|
| 2 Mar 2032 | 11,000,000 km | 29 |
| 19 Mar 2074 | 14,000,000 km | 37 |
| 10 Mar 2105 | 5,400,000 km | 14 |
| 11 Mar 2136 | 6,400,000 km | 17 |
| 8 Mar 2187 | 5,300,000 km | 14 |