Known for its remarkable astronomical events, Halley's Comet has been documented for over a millennium. It was last seen from Earth in 1986, and since it only appears every 75–79 years, July 2061 will mark the next sighting. Even though it seems far off, we can already look forward to its return. Halley's Comet is returning through the solar system and heading back towards Earth as of December 8, 2023.
The comet follows an elliptical orbit that is flattened as it passes beyond the solar system's outer bounds and then returns to the Sun. And now that it has spent decades moving away from our star, it has arrived at aphelion, the furthest point on its orbit. Situated approximately 472.2 million miles beyond Neptune's orbit, it is 3.27 billion miles from the Sun. Halley's Comet last passed through this location on its orbit in April 1948. Halley's comet is returning, which means that it will be approaching the Sun for the first time in almost 38 years.
As it approaches the inner solar system, its current speed of 0.565 miles per second, or roughly 2,034 miles per hour, is predicted to rise. According to Joe Rao from Space, "A celestial body moves fastest when it is at perihelion and slowest at aphelion in concert with Kepler's second law of motion." Therefore, on its journey inbound toward the Sun, Halley's orbital velocity will start to increase—very slowly at first—once it passes through aphelion.
The last time Halley's Comet was at perihelion, or its closest point to the Sun, was on February 9, 1986. On July 28, 2061, it will be there once more. If light pollution is not an issue, the comet will appear at least ten times brighter than it did 38 years ago because it will be on the same side of the Sun as Earth during the summer.
We can only speculate as to what technological advances scientists will have access to the next time Halley's Comet erupts, given that it was first observed in 1910 and studied with a probe 76 years later.