- Provisional designation is 1991 BA.
- Spotted in January 1991 passing unusually close to Earth.
- Follows its own orbit around the Sun.
- Orbit from beyond the Asteroid Belt to a point close to Venus's orbit.
- Passed within 171,000 km (106,000 miles) of Earth.
- Less than half the distance to the Moon.
- Closest known asteroid approach (passing - not striking).
- Calculations based on its brightness placed it at only 9 meters (about 30 feet) in diameter - a bus-sized object.
- Origin and destiny of 1991 BA unknown.
- It may be a true asteroid fragment.
- Parent may have been an asteroid which suffered a collision in the asteroid belt.
- After such a collision, the parent may have broken apart sending fragments into new orbits.
- Gravitational forces from Mars and Jupiter affect the paths of such fragments.
- This asteroid will orbit the Sun many times.
- Occasional close range encounters with Earth are likely.
- A collision with Earth's atmosphere would result in an explosion.
- Energy equivalent of explosion is about 40 kilotons of TNT.
- Or about 3 times the energy of the Hiroshima A-bomb!
- There is a 6 out of 7 chance it would occur over an ocean or polar region.
- This asteroid may pass close enough to radically alter its orbit.
- New orbit may take it on a collision course with Mars or Venus.
- Human technological advances in this new century have intriguing possibilities:
- A manned-probed to visit the asteroid for scientific research.
- A means to deflect the asteroid into a new trajectory.
- A reconnaisance mission to exploit its resources.