On Friday, Dec. 8, Halley’s Comet will commence with its 38-year journey to Earth. The popular space rock orbits the sun following a flattened elliptical orbit that drives it near to our star before taking it far away beyond the outer limits of our solar system. Astronomers revealed that Halley’s Comet arrived at perihelion on Feb. 9, 1986, moving the comet to its closest approach to the Sun.
Ever since then, the space rock started its return trip back to the outer region of the solar system. After its closest approach to the sun, the comet has been moving away from the Sun. Halley’s Comet will reach its aphelion at 8 p.m. Eastern Time on Friday, Dec. 8, (0100 GMT on Dec. 9.).
This region places the comet at its farthest distance from the sun at about 3.27 billion miles (5.26 billion km) distant. This implies that the 38-year journey is coming to an end tonight. When the comet reaches its aphelion, it will be at about 472.2 million miles (759.8 million km) beyond the orbit of Neptune.
Keep in mind that Neptune is the most distant known planet from the Sun. Hence, the comet will actually distance itself from the ice giant. Once Halley’s Comet reaches aphelion, its orbital velocity will slow down to about 0.565 miles (0.909 km) per second; that is roughly 2,034 miles (3,272 km) per hour.
Astronomers compared Halley’s current speed to its speed 38 years ago and realized the huge difference. When the comet was at its perihelion on Feb. 9, 1986, it was traveling at about 33.77 miles (54.52 km) per second, or 121,572 miles (195,609 km) per hour. However, its recent speed is way less than that.
When will Halley’s Comet Visit the Sun Again?
Astronomers analyzed the comet closely and realized that it would be visiting the sun once again in the future. According to Kepler’s second law of motion, a celestial body tends to move fastest when it is at perihelion and travel slowest at aphelion.
Hence, after the Halley comet completes its aphelion stage, its orbital velocity will begin to increase in speed as it heads towards the Sun. During its next closest flyby, the comet will pass the orbit of seven planets as it travels inbound toward our star. Astronomers describe the mean distance of the comet in astronomical units (AU).
Note that one astronomical unit is equivalent to the Earth’s mean distance from the sun which is 92,955,807 miles (149,597,870 km). Halley’s next journey through the solar system is noted as follows. The space rock will move across Neptune at 30.6 AU on May 7, 2041.
On May 1, 2053, Halley will flyby Uranus at 19.2 AU. On Dec. 7, 2058, Halley will fly across Saturn maintaining the distance of 9.54 AU. The comet will fly past Jupiter at a distance of 5.2 AU on June 25, 2060. On May 16, 2061, Halley’s comet will fly past Mars at a distance of 1.52 AU.
On June 19, 2061, the comet will fly past Earth at a distance of 1.0 AU. The comet will fly past Venus at 0.72 AU on July 9, 2061,. Finally, on July 28, 2061, Halley’s Comet will arrive at a perihelion for the second time since discovered.
Learn more about this comet from space.com.
