Strike! 10 biggest impact craters in the Solar System that show how chaotic our cosmic backyard really is

What are the biggest impact craters on Earth and across the Solar System?

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Published: Tuesday, 09 July 2024 at 07:25 AM

Our Solar System can a chaotic place, and you can see just how vulnerable many of its planets and moons are by studying the many impact craters that have been formed throughout its 4.5 billion-year history.

Here we’ll take a look at some of the best-known and biggest craters in the Solar System, with a special focus on Earth and how likely it is that our planet could suffer a sizeable impact.

Jupiter

Four images of Jupiter and the impact of fragment W of Comet Shoemaker-Levy 9, captured by the Galileo spacecraft on 22 July 1994 from a distance of 238 million km from Jupiter. Credit: NASA/JPL

Perhaps the most famous is the tale of comet Shoemaker–Levy 9, which broke up and impacted Jupiter in July 1994.

But even that was not the first known object to strike the planet.

Jupiter experiences the largest number of impacts of any planet and is often referred to as the ‘cosmic vacuum-cleaner’, hoovering up passing objects that could be a threat to the inner Solar System.

With a diameter of around 140,000km (87,000 miles), 11 times bigger than Earth’s, the giant planet is the largest in the Solar System and plays a key role in safeguarding Earth.

The Hubble Space Telescope captured this image of comet Shoemaker-Levy 9 on May 17, 1994. The stream of icy fragments stretched 1.1 million km across. Credit: NASA, ESA, and H. Weaver and E. Smith (STScI)
The Hubble Space Telescope captured this image of comet Shoemaker-Levy 9 on May 17, 1994.The stream of icy fragments stretched 1.1 million km across. Credit: NASA, ESA, and H. Weaver and E. Smith (STScI)

Its proximity to the inner Solar System, combined with its mass and enormous sphere of gravitational influence, has a huge effect on the distribution of smaller bodies orbiting the Sun, which are frequently captured by Jupiter.

Some of these comets escape the grasp of the gas giant and regain an orbit of the Sun, while others smash into the planet or, on rarer occasions, become one of its satellites.

In recent years, several impacts have been observed on Jupiter by amateur astronomers.

Image of Jupiter captured on 5 January 2024 by the Hubble Space Telescope. Credit: NASA, ESA, STScI, Amy Simon (NASA-GSFC)
Image of Jupiter captured on 5 January 2024 by the Hubble Space Telescope. Credit: NASA, ESA, STScI, Amy Simon (NASA-GSFC)

A bright flash caused by an object colliding with the planet was recorded by José Luis Pereira of Brazil in September 2021, and in August 2023 a collision was observed and recorded by an observer in China. 

Recent research questions how much of a protector Jupiter may be.

The colossal planet certainly deflects comets and asteroids away from Earth, but there’s evidence it may increase the frequency of short-period comets and asteroids that head our way. 

Not all objects are redirected and consumed by the gas giant, and the ones that have got away have inevitably impacted on other bodies within the Solar System.

There is evidence of these impact events all around us, with some of the largest collisions occurring uncomfortably close to home. 

It’s important to remember, though, that not all impacts are of significant size.

Earth

A map showing the location of the Chicxulub crater
An illustration showing the location of the Chicxulub crater, shortly after its formation. The Chicxulub crater is thought to be the impact scar left over from the asteroid that wiped out the dinosaurs and other species on Earth. Credit: Mark Garlick / Science Photo Library

According to NASA, 90 tonnes of material from outer space, ranging in size from tiny grains of cosmic dust to rocks, bombard Earth every day.

On a clear night, you may see some of this material zipping through Earth’s atmosphere as a meteor or ‘shooting star’.

Some of these meteors may land on Earth’s surface.

These meteorites are a reminder of how exposed we are to potential larger impacts from near-Earth objects (NEO), asteroids or comets passing within 45 million kilometres of Earth’s orbit.

The Vredefort Crater, the world’s oldest and largest known impact structure. NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S. Geological Survey.
The Vredefort Crater, the world’s oldest and largest known impact structure. NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S. Geological Survey.

One of Earth’s most significant impact craters is Chicxulub, located beneath the Yucatán Peninsula, Mexico, which formed around 66 million years ago.

The 200km-diameter (125-mile) crater was created when an asteroid 10km (6 miles) in diameter tore through Earth’s atmosphere and smashed into the surface.

An impact of this size caused a mass extinction event, wiping out three-quarters of life on Earth, including dinosaurs. 

But Chicxulub is not Earth’s largest crater – that title goes to crater Vredefort near Johannesburg in South Africa, with a whopping diameter of 300km (185 miles) and formed two billion years ago.

The Moon

A view of the lunar South Pole, centred on the Aitken Basin, as captuered by the Lunar Reconnaissance Orbiter's Lunar Orbiter Laser Altimeter. Credit: NASA/Goddard
A view of the lunar South Pole, centred on the Aitken Basin, as captuered by the Lunar Reconnaissance Orbiter’s Lunar Orbiter Laser Altimeter. Credit: NASA/Goddard

There are an estimated one million craters on the Moon with a diameter of more than a kilometre (0.6 miles), each one a perfect example of past impact events.

Unlike Earth, the Moon does not have a protective atmosphere, which makes it extremely vulnerable to incoming material hurtling towards its surface.

Consequently, the largest crater on the Moon is the South Pole–Aitken Basin, a massive 2,500km (1,550 miles) in diameter and between 6.2km and 8.2km (3.8–5 miles) deep.

It is the second-largest crater in the Solar System and is thought to have been caused by a low-velocity impact from an object 200km (125 miles) in diameter. 

Thankfully, humans weren’t around to witness these colossal impact events.

But today we can observe and record impacts across the Solar System thanks to powerful Earth- and space-based telescopes, and advances in space technology.

Mars

Impact crater on Mars as seen by the Mars Global Surveyor Orbiter. Credit: NASA/JPL/Malin Space Science Systems
Impact crater on Mars as seen by the Mars Global Surveyor Orbiter. Credit: NASA/JPL/Malin Space Science Systems

Since the late 1990s, spacecraft and landers visiting Mars have detected a whole host of new impact craters.

The Mars Global Surveyor orbited the Red Planet for 10 years and was the first spacecraft to map the surface in a resolution high enough to identify new impacts.

The craft detected its first impact between 2000 and 2001, and more than 1,200 impacts have been discovered by Martian orbiters and landers since then.

10 biggest impact craters in the Solar System

Utopia

The largest confirmed impact basin in the Solar System contains large quantities of underground ice

South Pole–Aitken Basin

The largest and deepest basin on the Moon, formed on the lunar far side 4.2 billion years ago

Hellas

Formed 3–4 billion years ago, Hellas crater was the first Martian feature to be discovered by telescope from Earth

Isidis

Likely to be the youngest impact basin to be created on Mars. Isidis Planitia lies within a basin

Argyre

Argyre crater was formed during the Late Heavy Bombardment 3.9 billion years ago

Caloris

Discovered on images taken by Mariner 10 in 1974, it is one of the largest impact basins in the Solar System

Sputnik Planitia Basin

The basin forms the western lobe of the heart-shaped Tombaugh Regio on Pluto

Imbrium

This impact crater formed on the Moon after a collision with a protoplanet 3.9 billion years ago

Rembrandt

The second-largest impact basin on Mercury. Discovered by the MESSENGER spacecraft in 2008

Rheasilvia

Created 1 billion years ago, the crater floor lies 13km (8 miles) below the surrounding surface

This article appeared in the July 2024 issue of BBC Sky at Night Magazine