A city-sized 'demon comet' is set to 'explode' tomorrow, say scientists who have discovered space rocks hurtling towards Earth and erupting every 15 days.

A city-sized comet heading towards Earth has exploded dozens of times this year, prompting scientists to reveal a pattern to its explosions – a 'hit'.

Dubbed the “Devil's Comet” because it sprouts horns during volcanic eruptions, the space rock appears to violently spew out ice and gas every 15 days.

The last event occurred on December 14, and the next event was placed on December 29 or 30.

Astronomers found that the cosmic body, officially known as Comet 12P, rotates over a two-week period, positioning its icy volcano vent toward the Sun and producing intense heat.

Richard Miles of the British Astronomical Society said Spaceweather.com: 'It's like 'Old Faithful'.

“Comet 12P contains a supercooling geyser, which erupts after local sunrise at its location.”

12P/Pons-Brooks is known as a cold volcanic or cold volcanic comet, which exhibits volcanic activity.

But instead of spewing molten rock and lava-like volcanoes onto Earth, an icy volcanic comet spews a mixture of gases and ice.

When a cold, volcanic comet approaches the Sun — as 12P/Pons-Brooks does — it heats up, causing increased pressure in the nucleus.

The pressure builds until the nitrogen and carbon monoxide explode, spewing icy debris through large cracks in the core's crust.

It's called Devil's Comet because it sprouts horns during an eruption like the one in October

After it makes its closest approach to us, the space rock will be returned to the outer solar system and will not return until 2095.

These gaseous streams can form distinctive shapes when viewed through a telescope, such as devil's horns, also described as a horseshoe or the Millennium Falcon from Star Wars.

This space rock is the size of the famous Halley's Comet, and was last seen with the naked eye on Earth in 1954.

It is also referred to as a “Halley-type comet” because its 71-year orbit around the Sun puts it in the same category as history's most famous space rock, which takes about 75 years to orbit our star, as opposed to thousands of years. Years like most comets.

Although Pons-Brooks will be at its closest to Earth in April 2024, it is expected to reach magnitude +4, so it will be visible to the naked eye in May and June 2024 as well.

It will be brightest in the night sky on June 2, 2024.

The comet's name is derived from the two astronomers who discovered it – Jean-Louis Pons and William Robert Brooks.

It was first discovered by Pons in 1812 and Brooks again in 1883, determining that Satan's Comet returns to our solar system every 71 years.

Since the 19th century, at least seven large explosions have been observed, SpaceWeather reports.

“2023 is on pace to match this number in just one year.”