Comet ISON disappeared as it circled the Sun November 18. Scientists speculate that the death of the "comet of the century" was certain as it was impossible to survive the immense heat and tidal forces so close to the Sun.

Owing to the large size of Comet ISON, often referred to as the "Comet of The Century", scientists were a little hopeful that the cosmic body would survive its close encounter with the Sun. However, all hopes were dashed when live feed of the comet approaching the Sun showed ISON disappearing behind the blazing star. What appeared a while later was a mere dull streamer.

While no official statement has been made about ISON's fate yet, scientists speculate that the "Comet of the century" died as it couldn't survive the immense heat and tidal forces so close to the Sun, according to a NASA press release. A news report by the space agency says that the comet grew faint while within the view of NASA's Solar Terrestrial Relations Observatory, and the joint European Space Agency and NASA's Solar and Heliospheric Observatory.  Astronomers continued to search for the comet but it was not visible at all in NASA's Solar Dynamics Observatory.

"We didn't see Comet ISON in SDO," said Dean Pesnell, project scientist for SDO. "So we think it must have broken up and evaporated before it reached perihelion."

According to a BBC report, the European Space Agency's experts on the Soho Sun-watching satellite confirmed the death of the comet at about 21:30 GMT.

"Our Soho scientists have confirmed, Comet Ison is gone," Esa's twitter feed announced.

According to evidence gathered regarding the encounter, researchers revealed that Ison was subjected to temperatures over 2,000C when it approached the Sun. They also state that the immense gravity of the star may have pulled and squeezed the object as it tumbled end over end. Researchers also said that Ison's nucleus was torn apart in the close pass, in the same way that Comet Lovejoy, a previous hopeful in 2011, was disrupted.

Some astronomers are still perplexed about the comet's end. They feel the death of the comet has left behind a lot of unsolved mysteries. Pesnell said that even if the comet broke up, its remains should have been visible in the magnetic field for 45 minutes.

"I'd like to know what happened to our half-mile of material that was going around the sun," USA Today quoted Pesnell as saying. "We should be able to see something."

Though they are not very hopeful, scientists have revealed plans to continue observing 11 telescopes in case the comet reappears.

The comet, which was discovered in September 2012 by the International Scientific Optical Network (ISON), near Kislovodsk, Russia, was believed to be a pristine cometary nucleus that had fallen from the hypothetical Oort Cloud, a reservoir of icy fragments left over from the birth of the solar system. It was reckoned that this "shell" of proto-comets is located around 1 light-year away from the sun.

Scientists had revealed earlier that if the comet survived its encounter with the Sun, it would have been visible through binoculars and maybe even the unaided eye in the second week of December, and would have made its closest approach to Earth Dec. 26. Earlier this year, the comet was lucky to survive a similar but not so intense sun-grazing encounter, though researchers had predicted minimal chances of survival.

Though all hope of a treat for sky watchers later in December has been lost, researchers revealed that the amount of information they were able to collect from observing the comet will provide great research opportunities for a long time to come.