Comet Hale–Bopp

 

Comet Hale-Bopp, long-period comet that was spectacularly visible to the naked eye, having a bright coma, a thick white dust tail, and a bright blue ion tail. It was discovered independently on July 23, 1995, by Alan Hale and Thomas Bopp, two American amateur astronomers, at the unusually far distance of 7.15 astronomical units (AU; about 1 billion km [600 million miles]) from the Sun, well beyond Jupiter’s orbit. The comet reached perihelion (closest distance to the Sun) at 0.914 AU on April 1, 1997, without ever coming very close to Earth (nearest distance 1.31 AU [196 million km, or 122 million miles]), because the comet passed through perihelion on the opposite side of the Sun from Earth and its orbit was almost perpendicular to that of Earth. From the comet’s rate of gas production, its nucleus was estimated to be at least 30 km (20 miles) in diameter.

Comet Hale-Bopp rounded the Sun and offered a dazzling spectacle in planet Earth's night skies. Digitized from the original astrophoto on 35mm color slide film, this classic image of the Great Comet of 1997 was recorded a few days after its perihelion passage on April 1, 1997. Made with a camera and telephoto lens piggy-backed on a small telescope, the 10 minute long, hand-guided exposure features the memorable tails of Hale-Bopp, a whitish dust tail and blue ion tail. Here, the ion tail extends well over ten degrees across the northern sky. In all, Hale-Bopp was reported as visible to the naked eye from late May 1996 through September 1997. Also known as C/1995 O1, Hale-Bopp is recognized as one of the most compositionally pristine comets to pass through the inner Solar System.

Who discovered Hale-Bopp?

Two amateur astronomers, Thomas Bopp in Arizona and Alan Hale in New Mexico, independently discovered the Hale-Bopp comet several years before it hit the headlines. Hale-Bopp was the furthest comet ever found by amateur astronomers at the time of its discovery.

On July 23, 1995, both men focused their telescopes on the neighboring globular cluster M70. Just a few days prior, Hale, who had a doctorate in astronomy but was running an educational organization, had looked at the same area, but now he noticed a brand-new blob in the region.

In a 1997 interview with Time magazine, he recalled, "As soon as I looked, I saw a fuzzy thing nearby. It was strange because I'd looked at M70 a couple of weeks earlier, and the item hadn't been there."

Several hours later, he recalled, he looked again and noted that the object had moved in the sky and reasoned that it must be a comet of some kind.

Bopp noticed the same item in the sky at almost the same time. Both individuals sent their observations to the Central Bureau for Astronomical Telegrams of the International Astronomical Union to officially record their findings.

The comet, formally known as C/1995 O1, stunned astronomers with how bright it appeared even while being far away. Even though experts anticipated the comet to be dazzling when it got closer to Earth, comets are difficult to predict since they are essentially simply balls of ice and dust that can change in unpredictable ways.

According to NASA, Bopp's closest approach to Earth took place on March 22, 1997, at a distance of approximately 120 million miles (193 million kilometers).

To put that into perspective, the Sun is 93 million miles (150 million kilometers) from Earth, so the comet came just a little bit closer than that to us.

At the time, another comet, the brilliant Hyakutake comet, had just passed by Earth in 1996, so it was still fresh in the minds of astronomers. But, despite being much farther away than Hyakutake, Hale-Bopp still appeared much brighter.

Where is the Hale-Bopp comet now, and when will it return?

During the comet's relatively brief pass by Earth, scientists raced to do as much research as they could. It was soon determined that it had been roughly 4,200 years since the comet had last been seen in Earth's night sky; if anyone took notice of it, then, of course. Likewise, it will be several millennia before it makes another trip to the inner solar system.

If correct, this means Hale-Bopp won't be seen again in the skies above Earth until about the year 4385 AD.

Four years after Hale-Bopp's closest approach to Earth, in 2001, the European Southern Observatory (ESO) published pictures of the comet. At that point, the comet was almost midway between the orbits of Saturn and Uranus, having traveled 1.2 billion miles (2 billion kilometers) from Earth.

Facts about Hale-Bopp

1. Hale-Bopp has a very long orbit around the Sun

2. Hale-Bopp actually clogged up the internet for a short time in 1997

3. The appearance of Hale-Bopp inspired some to take their own lives

4. We're yet to actually directly observe Hale-Bopp's nucleus

5. Hale-Bopp is larger than the asteroid that finished off the dinosaurs

6. Hale-Bopp is a record holder

7. Hale-Bopp is currently somewhere past Pluto

Purva A