Asteroid 2007 TU24, which measures between 160 and 650 yards wide, should be visible high in the sky from Britain to amateurs with small telescopes.
It will come within 334,000 miles of Earth - just 1.4 times the distance to the Moon - at 8.33am GMT tomorrow.
The last time such a large asteroid came so close to Earth was in September 1985, and the next comparable approach will be in 2027.
Prof Paul Murdin, of the Royal Astronomical Society, said: “It will be really exciting from a scientific point of view to be able to study an asteroid up close.
“For astronomers who work by bouncing radar off nearby objects, the nearer the asteroid, the clearer the picture – allowing us to study its shape, whether there are craters or any orbiting satellites.”
Images captured by NASA’s Goldstone radio telescope in California earlier this month show 2007 TU24 has an unusual shape and may have been formed from two separate asteroids stuck together.
The pictures also suggest the asteroid is rotating slowly, maybe every 10 to 30 hours.
Further information on its rate of rotation will provide astronomers with clues as to whether they are looking at solid rock or a loose collection of rubble.
If a large asteroid was ever discovered to be on a collision course with Earth, knowing its size, shape and rotation rate would be vital in order to plan for ways to deflect it.
If the skies are clear tomorrow night astronomers with telescopes with a 3ins diameter lens or larger should be able to see asteroid 2007 TU24 high in the sky in the Great Bear constellation.
NASA detects and tracks asteroids and comets approaching close to Earth through its Near Earth Object Observation Program to identify any with the potential to collide with our planet.
Click to view image: '145988-sciasteroid.jpg'
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