An asteroid is a minor planet—an object that is neither a true planet nor a comet—that orbits within the inner Solar System. They are rocky, metallic or icy bodies with no atmosphere. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter.

Of the roughly one million known asteroids the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in the main asteroid belt. Asteroids are generally classified to be of three types: C-type, M-type, and S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres, is almost 1000 km across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slightly elliptical, stable orbits, revolving in the same direction as the Earth and taking from three to six years to complete a full circuit of the Sun.

Asteroids have been historically observed from Earth; the Galileo spacecraft provided the first close observation of an asteroid. Several dedicated missions to asteroids were subsequently launched by NASA and JAXA, with plans for other missions in progress. NASA's NEAR Shoemaker studied Eros, and Dawn observed Vesta and Ceres. JAXA's missions Hayabusa and Hayabusa2 studied and returned samples of Itokawa and Ryugu, respectively. OSIRIS-REx studied Bennu, collecting a sample in 2020 to be delivered back to Earth in 2023. NASA's Lucy, launched in 2021, will study ten different asteroids, two from the main belt and eight Jupiter trojans. Psyche, scheduled for launch in 2023, will study a metallic asteroid of the same name.

Near-Earth asteroids can threaten all life on the planet; an asteroid impact event resulted in the Cretaceous–Paleogene extinction. Different asteroid deflection strategies have been proposed; the Double Asteroid Redirection Test spacecraft, or DART, was launched in 2021 and intentionally impacted Dimorphos in September 2022, successfully altering its orbit by crashing into it.

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Osiris-Rex: Nasa confirms return of asteroid Bennu samples

To play this video you need to enable JavaScript in your Dugway, UtahDusty samples from the "most dangerous known rock in the Solar System" have been brought to Earth.The American space agency Nasa landed the materials in a capsule that came down in the West Desert of Utah state.

Osiris-Rex: Asteroid Bennu 'is a journey back to our origins'

Nasa's Osiris-Rex capsule will come screaming into Earth's atmosphere on Sunday at more than 15 times the speed of a rifle bullet. It will make a fireball in the sky as it does so, but a heat shield and parachutes will slow the descent and bring it into a gentle touchdown in Utah's West Desert.

Psyche: Metal world mission targets 'iron volcanoes'

Up until now, the worlds we've visited with robotic spacecraft have been composed largely of rock, ice and gas. But a Nasa mission due to launch in 2022 will visit an object thought to be made largely of metal.

Massive asteroid to pass by Earth on weekend

An asteroid large enough to destroy a city will pass between the orbits of the Earth and the Moon this weekend - luckily for us, missing both. The object, named 2023 DZ2, was discovered a month ago.

Asteroid to pass closer than some satellites

You definitely shouldn't panic but there is a biggish asteroid about to pass by Earth in the coming hours. About the size of a bus, the space rock, known as 2023 BU, will whip over the southern tip of South America just after midnight GMT.

Nasa's Dart spacecraft 'changed path of asteroid'

The American space agency says its recent attempt to deflect the path of an asteroid was successful. Scientists have now confirmed the orbit of a 160m-wide (520ft) space rock known as Dimorphos was altered when the Dart probe struck it head on last month.

Asteroid struck by Nasa probe leaves 10,000km trail

BBC NewsA new image shows that an asteroid which was deliberately struck by Nasa's Dart probe has left a trail of debris stretching thousands of kilometres. A telescope in Chile captured the remarkable image of a comet-like plume spreading behind the giant rock.

Dimorphos: Nasa flies spacecraft into asteroid in direct hit

To play this video you need to enable JavaScript in your browser.By Jonathan AmosBBC Science Correspondent@BBCAmosThe American space agency's Dart probe has smashed into an asteroid, destroying itself in the process.

Nasa spacecraft lining up to smash into an asteroid

In the coming hours, the American space agency will crash a probe into an asteroid. Nasa's Dart mission wants to see how difficult it would be to stop a sizeable space rock from hitting Earth.

Impact crater may be dinosaur killer's baby cousin

When an asteroid slammed into what is now the Gulf of Mexico 66 million years ago, wiping out the dinosaurs, did it have a companion? Was Earth bombarded on that terrible day by more than one space rock?

Tanis: Fossil found of dinosaur killed in asteroid strike, scientists claim

To play this video you need to enable JavaScript in your browser.By Jonathan AmosBBC Science Correspondent@BBCAmosScientists have presented a stunningly preserved leg of a dinosaur.

Don't Look Up: What's the plan to deal with asteroids and comets?

It's understandable if the thought of a comet wiping out all life on earth might be an extra worry you just don't need right now. But if you've watched Netflix movie Don't Look Up, it might be hard to get the thought out of your mind.

Nasa Dart asteroid spacecraft: Mission to smash into Dimorphos space rock launches

Nasa's Dart mission wants to see how difficult it would be to stop a sizeable space rock from hitting Earth. The spacecraft will crash into an object called Dimorphos to see how much its speed and path can be altered.

Apophis asteroid will not hit Earth for 100 years, Nasa says

Earthlings can breathe a sigh of relief after US space agency Nasa confirmed the planet was "safe" from a once-feared asteroid for the next 100 years at least. Nasa had deemed Apophis to be one of the most dangerous asteroids to Earth after its discovery in 2004.

Asteroid that wiped out dinosaurs shaped fortunes of snakes

Snakes owe their success in part to the asteroid strike that wiped out the dinosaurs, according to a new study. The impact caused devastation, with most animals and plants dying out.

The Day the Dinosaurs Died – Minute by Minute

DISCOVER ANCIENT WORLDS Peek into the past and learn about dinosaurs and other amazing creatures: Sources & further reading: 66 million years ago, maybe on a Tuesday afternoon, life was the same as it had been the day b

'Oumuamua Is Not Aliens

To learn to think like a scientist check out To repeat the space time maxim: it’s never aliens … until it is. So let’s talk about ‘oumuamua. You can further support us on Patreon at Get your own Space Time t­-shirt at

Dinosaur-killing asteroid strike gave rise to Amazon rainforest

The asteroid impact that killed off the dinosaurs gave birth to our planet's tropical rainforests, a study suggests. Researchers used fossil pollen and leaves from Colombia to investigate how the impact changed South American tropical forests.

Hayabusa-2: Pieces of an asteroid found inside space capsule

Scientists have been greeted by the sight of jet black chunks of rock and soil from an asteroid after opening a capsule that returned from deep space a week ago.

Hayabusa-2: Capsule with asteroid samples in 'perfect' shape

A capsule containing the first significant quantities of rock from an asteroid is in "perfect" shape, according to scientists.The container with material from a space rock called Ryugu parachuted down near Woomera in South Australia on Saturday evening (GMT).

Hayabusa-2: Rocks from an asteroid set for delivery to Earth

The first large sample of rock and soil from an asteroid is making its way back to Earth. The sample container should deploy parachutes and land in the Australian outback this evening.

Osiris-Rex: Nasa probe risks losing asteroid sample after door jams

image copyrightReutersA Nasa probe sent to collect rock from an asteroid several hundred million kilometres from Earth has grabbed so much that samples are spilling out.

Earth's oldest asteroid impact 'may have ended ice age'

Scientists have identified the world's oldest asteroid crater in Australia, adding it may explain how the planet was lifted from an ice age. The asteroid hit Yarrabubba in Western Australia about 2.2 billion years ago - making the crater about half the age of Earth, researchers say.

Bizarre shape of interstellar asteroid

An asteroid that visited us from interstellar space is one of the most elongated cosmic objects known to science, a study has shown. Discovered on 19 October, the object's speed and trajectory strongly suggested it originated in a planetary system around another star.

Asteroid makes near-miss fly-by

An asteroid hurtled past the Earth on Friday in something of a cosmic near-miss, making its closest approach at about 1600 GMT. The asteroid, estimated to be about 11m (36ft) in diameter, was first detected on Wednesday.

Asteroid Themis has 'frosted surface'

Scientists have detected water-ice on the surface of an asteroid. The first-time observation was made on 24 Themis, a huge rock that orbits almost 480 million km out from the Sun.

Asteroid Lutetia has thick blanket of debris

Lutetia, the giant asteroid visited by Europe's Rosetta probe in July, is covered in a thick blanket of dusty debris at least 600m (2,000ft) deep. Aeons of impacts have pulverised the space rock to produce a shattered surface that in terms of texture is much like Earth's Moon, scientists say.

A perfect view of the asteroid capsule's Earth return

Nothing can prevent it now. Japan's Hayabusa spacecraft is heading home after its seven-year round-trip to the asteroid Itokawa. I wrote earlier in the week about some of the woes Hayabusa experienced as it tried to grab dusty fragments from Itokawa's surface, and now it faces one last challenge.

'Life chemicals' may have formed around far-flung star

There is now even more evidence that life on Earth may have been seeded by material from asteroids or comets. Prior research has shown how amino acids - the building blocks of life - could form elsewhere in the cosmos.

'Crater' spied under California

Oil exploration work in California's Central Valley region has uncovered a possible space impact crater. The 5.5km-wide bowl is buried under shale sediments west of Stockton, in San Joaquin County, and is thought to be between 37 and 49 million years old.

BBC NEWS | UK | Magazine | 'A meteorite smashed through my roof'

The chances of being hit by a chunk of space rock are measured in the billions-to-one. Roy Fausset, 59, had the closest of escapes last month when what scientists now say was a meteorite crashed through his New Orleans home.

Hayabusa capsule particles may be from asteroid

A canister recovered from the first spacecraft to land on an asteroid and return to Earth, contains dust particles, say Japanese scientists. Japan's space agency (Jaxa) began to open the Hayabusa craft's sample container on 24 June.

The 'cosmic dust' sitting on your roof

It's in the dirt on the ground, the debris on your roof, and the dust that tickles your nose – tiny pieces of "cosmic dust", everywhere. These microscopic particles from outer space are micrometeorites – mostly the debris from comets and asteroids – and they have settled all over our planet.

Winchcombe meteorite bolsters Earth water theory

By Jonathan AmosBBC Science Correspondent@BBCAmosA meteorite that crashed on the Gloucestershire town of Winchcombe last year contained water that was a near-perfect match for that on Earth.

Somalia meteorite: Joy as scientists find two new elements

Image source, Supplied to University of AlbertaBBC NewsA huge meteorite that fell to Earth contains two minerals never seen before on our planet, scientists say.Canadian researchers said the rock was found in rural Somalia two years ago, but locals believe it is much older.

US detects huge meteor explosion

The blast was the second largest of its kind in 30 years, and the biggest since the fireball over Chelyabinsk in Russia six years ago. But it went largely unnoticed until now because it blew up over the Bering Sea, off Russia's Kamchatka Peninsula.

James Webb Space Telescope hit by tiny meteorite

The damage inflicted by the dust-sized micrometeoroid is producing a noticeable effect in the observatory's data but is not expected to limit the mission's overall performance. James Webb was launched in December to succeed the revolutionary - but now ageing - Hubble Space Telescope.

Christie's auction: Kennel hit by meteorite goes on sale

A chunk of Mars, some of the space rock that splattered a quiet English town and a dog kennel pierced by an object that came out of the sky.All three items go under the hammer on Wednesday when London auction house Christie's holds its annual sale of rare and unusual meteorites.

Large meteor wows Norway after blazing through night sky

Norwegians have been left awestruck by what experts say was an unusually large meteor that illuminated the night sky in the country's south-east. Footage shows powerful flashes of light over Norway, followed by what witnesses described as loud bangs on Sunday.

US meteorite adds to origins mystery

In January 2018, a falling meteorite created a bright fireball that arced over the outskirts of Detroit, Michigan, followed by loud sonic booms. The visitor not only dropped a slew of meteorites over the snow-covered ground, it also provided information about its extra-terrestrial source.

Nasa Mars rover: Meteorite to head home to Red Planet

Nasa's Perseverance robot will carry with it a meteorite that originated on the Red Planet and which, until now, has been lodged in the collection of London's Natural History Museum (NHM). The rock's known properties will act as a calibration target to benchmark the workings of a rover instrument.

Antarctic meteorites yield global bombardment rate

It's in excess of 16,000kg. This is for meteorite material above 50g in mass. It doesn't take account of the dust that's continuously settling on the planet, and of course just occasionally we'll be hit by a real whopper of an asteroid that will skew the numbers.

Meteorites 'could have carried nitrogen to Earth'

A meteorite found in Antarctica could lend weight to the argument that life on Earth might have been kick-started from space, scientists are claiming.Chemical analysis of the meteorite shows it to be rich in the gas ammonia.

Doubts over Latvia 'meteor crash'

Scientists investigating a large crater in a field in northern Latvia, believed to have been caused by a meteorite, now suspect it was a hoax. Fire crews were called to the scene on Sunday outside the town of Mazsalaca by locals who said something had fallen from the sky and set the land on fire.

Green comet approaching Earth for first time in 50,000 years

BBC NewsA bright green comet is set to swing by Earth's outer space for the first time in 50,000 years, and may hang around for a month.NASA officials said the icy visitor was first spotted in March 2022 while it was inside the orbit of Jupiter.

Astronomy Photographer of the Year: 'Once in a lifetime' picture of comet wins award

The image shows a piece of Comet Leonard's tail breaking off and being carried away by the solar wind. The comet made a brief appearance to Earth after being discovered in 2021, but has now left our Solar System.

Nasa scientists spy 'largest comet ever seen'

Nasa's Hubble telescope has determined the comet's icy nucleus has a mass of about 500 trillion tonnes and is 85 miles (137km) wide - larger than the US state of Rhode Island. But not to worry. The closest it will get is one billion miles away from the Sun, and that won't be until 2031.

C/2014 UN271 (Bernardinelli-Bernstein)

C/2014 UN271 (Bernardinelli-Bernstein), or simply 2014 UN271, is a large Oort cloud comet discovered by astronomers Pedro Bernardinelli and Gary Bernstein in archival images from the Dark Energy Survey.[6][7] When first imaged in October 2014, the object was 29 AU (4.

Woah! Giant Comet/Minor Planet Is Approaching From Oort Cloud

Good telescope that I've used to learn the basics: Get a Wonderful Person shirt: Alternatively, PayPal donations can be sent here: Hello and welcome! My name is Anton and in this video, we will talk about a

The mysteries of the icy cloud around our Solar System

For a few weeks in the summer of 2020, if you had been looking up on a clear night, there is a chance you might have spotted a rare visitor to our part of the Solar System.

First measurements of 'interstellar comet'

Astronomers are gathering measurements on a presumed interstellar comet, providing clues about its chemical composition. The object, C/2019 Q4 (Borisov), is only the second interstellar object ever identified, after 'Oumuamua, which was spotted in 2017.

Has another interstellar visitor been found?

An amateur astronomer has discovered a comet that could come from outside our Solar System. If so, it would be the second interstellar object after the elongated body known as 'Oumuamua was identified in 2017.

'Alien comet' visitor has weird composition

image copyrightNRAO/AUI/NSF, S. DagnelloThe first known comet to visit us from another star system has an unusual make-up, according to new research.The interstellar comet 2I/Borisov was detected in our Solar System last year.

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