Hale-Bopp: The famous 90s comet that took the world by storm

Back in the mid-1990s, a single comet unexpectedly appeared in the skies above Earth. This event sparked a global fascination with the object, for obvious reasons.
Christopher McFadden
Comet Hale-Bopp over Indian Cove.
Comet Hale-Bopp over Indian Cove.

Wally Pacholka/NASA 

  • Hale-Bopp suddenly appeared in 1997 and created a lot of excitement around the planet.
  • The comet was incredibly bright and could be seen during the night and day for 18 months.
  • Many interesting findings were made about the comet, but its visit also triggered a wealth of UFO sightings and one very tragic event.

Back in 1997, a single comet caused a media storm when it passed close to Earth. People from around the world became obsessed with this mysterious celestial object for several months as it made its way through the Solar System.

But the story didn't end there.

Hale-Bopp helped improve our understanding of comets in many interesting ways and was a priceless event, scientifically speaking. It also raised the profile of astronomy in general for an entirely new generation of children.

But, there were also some darker consequences of the comet's unannounced appearance in the skies above Earth.

What was Hale-Bopp?

Back in 1997, an extraordinarily bright comet known as Hale-Bopp passed by Earth. For almost 18 months, it was visible to the unaided eye and was a stunning sight for anyone living in the Northern Hemisphere.

Hale-Bopp: The famous 90s comet that took the world by storm
Comet Hale-Bopp.

During this short period of time, the comet became something of a household name, making it as, if not more, famous than other comets like Halley's Comet.

According to NASA, the comet was one of the brightest comets ever recorded to enter the inner solar system, with an absolute magnitude of -1. For reference, absolute magnitude is the apparent magnitude a comet would have if it was observed at a distance of 1 AU from the Earth and the Sun. On this scale, the lower the number, the brighter the object is, and each increase in integer represents an increase in brightness of 2.5 times.

The Sun, for example, has an absolute magnitude of 4.83 (the absolute magnitude of a star is its apparent magnitude measured as if it were 10 parsecs away from the observer).

At the same distance, Hale-Bopp was 130 times brighter than Halley's Comet. It was so bright, in fact, that even from light-polluted areas like Chicago, its twin blue and white tails could be seen very clearly.

An impressive event, but it also led to some notable tragedies around the world. For example, when the comet approached Earth, 39 members of the San Diego "Heaven's Gate" cult committed mass suicide. But, more on that later.

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?

Hale-Bopp: The famous 90s comet that took the world by storm
The last time Hale-Bopp visited Earth was during the early-Bronze Age.

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.

"The large 'dirty snowball' nucleus of ice and dust (probably about 50 km (31 miles) diameter) continues to be active, despite the very low temperature where it is now. This is quite unusual for a comet," ESO explained.

It is very difficult to forecast a comet's brightness, which makes studying comets rather difficult.

To help us understand comets better, certain missions, like Europe's Rosetta probe, have been developed to study them in very close quarters.

This probe actually orbited Comet 67P/Churyumov-Gerasimenko from 2014 to 2016 to investigate what goes on as a comet approaches the Sun at its closest point. Rosetta's research will enable scientists to more accurately anticipate how bright comets will be.

While occasional amateur discoveries of comets still occur (like Hale-Bopp), automated spacecraft tend to make the most discoveries in recent years. For instance, the Solar and Heliospheric Observatory (SOHO) satellite is placed optimally to observe sun-grazing comets because it is intended to research solar activity.

Hale-Bopp: The famous 90s comet that took the world by storm
Close up of the comet Neowise.

Since its launch into orbit in 1995, SOHO has photographed around 4,000 comets.

Why were so many UFOs spotted when Hale-Bopp appeared?

One interesting impact of the appearance of Hale-Bopp in 1997 was an apparent uptick in Unidentified Flying Object (UFO) sightings just before, during, and after its journey.

In fact, in the United Kingdom alone, something like 1,035 eyewitness reports of UFOs were submitted to the Ministry of Defence (MOD) between 1996 and 1997.

Across the globe, other eyewitness reports, some with "evidence," were also published.

Hale-Bopp: The famous 90s comet that took the world by storm
Jet fighter engaging a UFO.

One such example appeared in November of 1996. The image appeared to show a blurry, slightly elongated object visible near the comet. This image was taken by Chuck Shramek of Houston, Texas, using a charged-couple device (CCD) digital format. In the image, one of the background stars displayed some spikes, giving it a "Saturn-like" look.

Shramek called the Art Bell radio show Coast to Coast AM to announce that he had found a "Saturn-like object" following Hale-Bopp after his computer sky-viewing program failed to detect the star.

Although the "Saturn-like object" was later identified as star SAO 141894 (which has an absolute magnitude of 8.5) by comparing it to the Palomar Sky Survey, the rumor spread among UFOlogists that the object was actually a huge spacecraft.

Many scientists, including Alan Hale, argued that Shramek must have made errors when configuring his software, leading to confusion, but this did not stop UFO enthusiasts from quickly coming to the conclusion that an alien ship must be tracking the comet. One of the most high-profile proponents of this theory was the then professor of political science at Emory University Courtney Brown. 

Hale-Bopp: The famous 90s comet that took the world by storm
Hale-Bopp's visit coincidede with an increase in UFO sightings.

Another apparent image of a UFO also surfaced soon after. Art Bell claimed to have obtained an image of the object from an anonymous astrophysicist who was about to confirm its discovery.

The purported image, according to astronomers Olivier Hainaut and David Tholen of the University of Hawaii, actually turned out to be a modified version of one of their own comet photos. 

While not technically an example of a UFO sighting, some even attempted to claim that Hale-Bopp was a hoax created to divert attention from "Nibiru" or "Planet X."

This planet, allegedly, is massive, and its close approach will alter the Earth's rotation and cause a global apocalypse at some time in the future. One of the main proponents of this hoax theory was Nancy Lieder, a self-described psychic who also claimed to receive signals from aliens through an implant in her brain.

Hale-Bopp: The famous 90s comet that took the world by storm
Quite why so many more UFO sightings were reported is not fully understood.

She first predicted the end of the world in May 2003, but, as we know, nothing happened. Nevertheless, a number of conspiracy websites continued to warn of the arrival of Nibiru, with the majority of them linking it to the year 2012 and the close of the Mayan long-count period.  

Scientists have frequently refuted the claims of Lieder and others regarding the existence of the planet Nibiru.

Then, of course, there were the tragic events of the "Heaven's Gate" suicide cult. But we'll cover that tragedy below.

Facts about Hale-Bopp

You should already have a wealth of information about one of the most famous comets ever discovered. But, if you are still hungry for more, then here are a few select facts about Hale-Bopp.

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

Hale-Bopp: The famous 90s comet that took the world by storm
An artist's impression of the Oort cloud and the Kuiper belt.

According to sources like Swinburne University of Technology, Comet Hale-Bopp is a long-period comet. This means that it is a comet with an orbital period longer than 200 years. Compared to short-period comets, long-period comets typically have very elliptical orbits, making them less predictable.

Like most long-period comets, Hale-Bopp presumably came from the Oort Cloud, a spherical cluster of ice particles around 2,000 to 100,000 Astronomical Units (AU) from the Sun. For reference, one AU, or roughly 93 million miles (150 million kilometers), is the distance between Earth and the Sun.

Because objects in the Oort Cloud are so far from the Sun, they are much more influenced by other cosmic gravitational forces like other stars, molecular clouds, or even the tidal forces of the Milky Way. This influence can, and often does, pull some of these objects from the cloud and place them in orbits that can bring them into the solar system properly.

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

When the comet first became visible in 1997, it caused quite a storm in digital and printed media. At the time, the internet was a new but rapidly expanding public phenomenon.

However, the interest in the comet by the general public almost caused a major issue for the fledgling technology.

In March 1997, Scientific American reported that there were "a multitude of websites containing information on Hale-Bopp; they are attracting so many visitors that they are causing a traffic jam on the Internet." Over the Easter weekend, a Hale-Bopp webpage made up at NASA's Jet Propulsion Laboratory received more than 1.2 million hits per day and had two mirror sites set up as well.

Of course, not just amateurs were watching the show. As the comet approached, expert telescopes swung into position to observe it. NASA even studied the comet using the impressive imaging power of the Hubble Space Telescope and reported that the comet's nucleus is "huge," at between 19 miles (30km) and 25 miles (40 km) across.

Hale-Bopp: The famous 90s comet that took the world by storm
Image of Hale-Bopp in 1997.

This was impressive enough, but scientists were also astonished to discover that the sheer volume of material bursting from the comet was also enormous. According to estimates made at the time, Hale-Bopp was erupting something like eight times the average for all comets observed up to that time.

The Hubble study's principal investigator, Harold Weaver of Johns Hopkins University, noted that the surface of Hale-nucleus Bopp's "must be an incredibly dynamic place, with 'vents' being turned on and off as new patches of icy material are rotated into sunlight for the first time."

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

The appearance of Hale-Bopp turned out to be an exciting event for many, but was also tainted with its fair share of tragedy.

Marshall Applewhite, a former music professor and proponent of sexual abstinence (who had also had himself castrated), was the leader of an end-times cult known as "Heaven's Gate."

Members of the cult thought that their physical bodies were only containers that could be discarded in favor of a higher physical existence. They also believed that Hale-Bopp was being followed by an alien spaceship.

Cult members were led to believe that if they took their own lives, they would leave their physical bodies, board the presumed alien spaceship, and enter a state of "higher existence."

Hale-Bopp: The famous 90s comet that took the world by storm
Rancho Santa Fe, where the group members of Heaven's Gate committed mass suicide.

So, in late March 1997, Applewhite and 38 followers ingested a lethal cocktail of phenobarbital and vodka and laid down in preparation for their "journey." Later, in a mansion in the suburbs of San Diego, California, bunk beds were discovered by authorities containing the bodies of 21 women and 18 men.

They were lying peacefully, wearing matching dark clothes and Nike sneakers

The New York Times reported in March 1997 that information the group put up on its website suggested that the timing of the suicides was tied to the arrival of the Hale-Bopp comet, which members appeared to regard as a cosmic ambassador inviting them to another plane of existence.

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

Hale-Bopp: The famous 90s comet that took the world by storm
Grainy image of Hale-Bopp from 1997.

As we've already covered above, Hale-Bopp's nucleus is unusually large for a comet. During its time near Earth in 1997, it also proved to be incredibly bright.

While scientists are confident that the nucleus is made up of ice, rock, and dust, this is only really an educated guess.

This is because, unlike Halley's Comet, the nucleus of Hale-Bopp has not yet been directly photographed.

During its final journey through the inner Solar System, this massive nucleus expelled a significant amount of gas and dust particles. Isolated ice fragments from the comet showed erratic outbursts, which suggested the nucleus was probably very dynamic.

Hale-Bopp: The famous 90s comet that took the world by storm
The Pic du Midi Observatory image in question.

Just two hours after the 1997 perihelion, the Pic du Midi Observatory captured an image that revealed something interesting about the comet's nucleus too.

It showed that the Hale-Bopp Comet is encircled by a double-shell system of dust. Some think that the presence of a binary nucleus could account for the extremely bright display.

While it sounds convincing, this theory hasn't been verified yet.

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

Hale-Bopp, as we've already explained, is a pretty big comet, all things considered. In fact, it is about six times larger than another famous comet, Halley's Comet.

What's more, its size is believed to be roughly five times bigger than the asteroid theorized to have hit the Earth and wiped out the dinosaurs, so says NASA.

For reference, Hale-Bopp is estimated to have a diameter of around 37 miles (60 kilometers) across. Since the asteroid (meteorite) that formed the Chixulub Crater in Mexico was atomized during the impact, calculating its dimensions is a little harder to pinpoint.

However, efforts were made in the 1980s to estimate its size, with the most commonly accepted dimensions coming in at around 4.1 miles (6.6 km) in diameter. This object may even have also been a comet, but its exact nature is very much a matter of hot debate.

Given the devastation wrought by the dinosaur-killing meteorite, if a comet the size of Hale-Bopp were to ever impact the Earth, it would likely result in one of the worst mass extinction events the Earth has ever seen.

6. Hale-Bopp is a record holder

The Hale-Bopp Comet, which was visible for 18 months, is regarded as the longest-visible comet in history. The previous record-holder before its unexpected appearance was C/1811 F1. Also known as the Great Comet of 1811, this comet was a visual treat that lasted a "mere" 260 or so days.

Not only that, but Hale-Bopp was one of the brightest and most active ever recorded. Astronomers discovered that it produced significantly more gas and dust than other comets as it approached the Earth.

Surprisingly, astronomers also observed a third tail between the usual two, which was apparently primarily composed of sodium.

Hale-Bopp: The famous 90s comet that took the world by storm
Hale-Bopp was so bright, it could be seen during the day.

On April 1, 1997, Comet Hale-Bopp reached its perihelion (its closest approach to the Sun). By that point, it had become extremely bright, with an apparent magnitude of roughly -1.8. The comet blazed brighter than every other star in the night sky except for Sirius.

The comet was so bright, in fact, that it could be seen during the day at times too. Its tail stretched across the sky at a 45-degree angle.

7. Hale-Bopp is currently somewhere past Pluto

Hale-Bopp was estimated to be traveling close to about 98,000 miles per hour (157,711 kilometers per hour) when it was first observed in 1997. After sticking around for 18 months, the comet continued its elongated orbit back out toward the far distant reaches of our Solar System.

Since then, it has had almost two decades to continue its journey and has now traveled a great distance from us.

In fact, Hale-Bopp is currently nearly the same distance from the Sun as Pluto and is situated in the constellation of Octans at a distance of about 39.5 AU.

The comet was visible to powerful ground-based telescopes until about 2020 but has now faded to an estimated magnitude of around +25.6, making it very difficult to spot.

At the farthest point in its orbit, the comet will be 370.8 AU from the Sun.

And that, Hale-Bopp enthusiasts, is your lot for today.

Hale-Bopp was an unprecedented celestial event for anyone alive in the 1990s. Last seen during the Bronze Age, humans won't be able to experience the same event for several thousand more years.

Quite how the world will look at that time or whether people will actually be able to visit the comet is anyone's guess. That is, if humans still occupy Earth or the Solar System.

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