{"id":109607,"date":"2025-02-05T04:03:35","date_gmt":"2025-02-05T04:03:35","guid":{"rendered":"https:\/\/chezaspin.com\/blog\/index.php\/2025\/02\/05\/astronomers-have-spied-an-asteroid-that-may-be-heading-for-earth-heres-what-we-know-so-far\/"},"modified":"2025-02-05T04:03:35","modified_gmt":"2025-02-05T04:03:35","slug":"astronomers-have-spied-an-asteroid-that-may-be-heading-for-earth-heres-what-we-know-so-far","status":"publish","type":"post","link":"https:\/\/chezaspin.com\/blog\/astronomers-have-spied-an-asteroid-that-may-be-heading-for-earth-heres-what-we-know-so-far\/","title":{"rendered":"Astronomers have spied an asteroid that may be heading for Earth. Here\u2019s what we know so\u00a0far"},"content":{"rendered":"

Jonti Horner<\/a>, University of Southern Queensland<\/a><\/em><\/p>\n

On 27 December last year, astronomers using the ATLAS survey telescope in Chile discovered a small asteroid moving away from Earth. Follow up observations have revealed that the asteroid, 2024 YR4, is on a path that might lead to a collision with our planet on December 22 2032.<\/p>\n

In other words, the newly-discovered space rock poses a significant impact threat to our planet.<\/p>\n

It sounds like something from a bad Hollywood movie. But in reality, there\u2019s no need to panic \u2013 this is just another day living on a target in a celestial shooting gallery.<\/p>\n

So what\u2019s the story? What do we know about 2024 YR4? And what would happen if it did collide with Earth?<\/p>\n

A target in the celestial shooting gallery<\/h2>\n

As Earth moves around the Sun, it is continually encountering dust and debris that dates back to the birth of the Solar system. The system is littered with such debris, and the meteors and fireballs seen every night are evidence of just how polluted our local neighbourhood is.<\/p>\n

But most of the debris is far too small to cause problems to life on Earth. There is far more tiny debris out there than larger chunks \u2013 so impacts from objects that could imperil life on Earth\u2019s surface are much less frequent.<\/p>\n

The most famous impact came some 66 million years ago. A giant rock from space, at least 10 kilometres in diameter, crashed into Earth \u2013 causing a mass extinction that wiped out something like 75 per cent of all species on Earth.<\/p>\n

Impacts that large are, fortunately, very rare events. Current estimates suggest that objects like the one which killed the dinosaurs only hit Earth every 50 million years or so. Smaller impacts, though, are more common.<\/p>\n

On June 30 1908, there was a vast explosion in a sparsely populated part of Siberia. When explorers later reached the location of the explosion, they found an astonishing site: a forest levelled, with all the trees fallen in the same direction. As they moved around, the direction of the fallen trees changed \u2013 all pointing inwards towards the epicentre of the explosion.<\/p>\n

<\/a>The Tunguska event flattened trees over an area of around 2,200 square kilometres. Leonid Kulik \/ Wikimedia<\/a><\/p>\n

In total, the Tunguska event levelled an area of almost 2,200 square kilometres \u2013 roughly equivalent to the area of greater Sydney. Fortunately, that forest was extremely remote. While plants and animals were killed in the blast zone, it is thought that, at most, only three people perished.<\/p>\n

Estimates vary of how frequent such large collisions should be. Some argue that Earth should experience a similar impact, on average, once per century. Others suggest such collisions might only happen every 10,000 years or so. The truth is we don\u2019t know \u2013 but that\u2019s part of the fun of science.<\/p>\n

More recently, a smaller impact created global excitement. On 15 February 2013, a small asteroid (likely about 18 metres in diameter) detonated near the Russian city of Chelyabinsk.<\/p>\n

The explosion, about 30 kilometres above the Earth\u2019s surface, generated a powerful shock-wave and extremely bright flash of light. Buildings were damaged, windows smashed, and almost 1,500 people were injured \u2013 although there were no fatalities.<\/p>\n

It served as a reminder, however, that Earth will be hit again. It\u2019s only a question of when.<\/p>\n

Which brings us to our latest contender \u2013 asteroid 2024 YR4.<\/p>\n

The 1-in-77 chance of collision to watch<\/h2>\n

2024 YR4 has been under close observation by astronomers for a little over a month. It was discovered just a few days after making a relatively close approach to our planet, and it is now receding into the dark depths of the Solar System. By April, it will be lost to even the world\u2019s largest telescopes.<\/p>\n

The observations carried out over the past month have allowed astronomers to extrapolate the asteroid\u2019s motion forward over time, working out its orbit around the Sun. As a result, it has become clear that, on December 22 2032, it will pass very close to our planet \u2013 and may even collide with us.<\/p>\n

<\/a>The area at risk of a strike, based on current (highly uncertain) data. Daniel Bamberger \/ Wikimedia<\/a>, CC BY-SA<\/a><\/p>\n

At present, our best models<\/a> of the asteroid\u2019s motion have an uncertainty of around 100,000 kilometres in its position at the time it would be closest to Earth. At around 12,000 kilometres in diameter, our planet falls inside that region of uncertainty.<\/p>\n

Calculations suggest there is currently around a 1-in-77 chance that the asteroid will crash into our planet at that time. Of course, that means there is still a 76-in-77 chance it will miss us.<\/p>\n

When will we know for sure?<\/h2>\n

With every new observation of 2024 YR4, astronomers\u2019 knowledge of its orbit improves slightly \u2013 which is why the collision likelihoods you might see quoted online keep changing. We\u2019ll be able to follow the asteroid as it recedes from Earth for another couple of months, by which time we\u2019ll have a better idea of exactly where it will be on that fateful day in December 2032.<\/p>\n

But it is unlikely we\u2019ll be able to say for sure whether we\u2019re in the clear at that point.<\/p>\n

<\/a>Recent observations of 2024 YR4 \u2013 the faint unmoving dot in the centre of the image. ESO<\/a>, CC BY<\/a><\/p>\n

Fortunately, the asteroid will make another close approach to the Earth in December 2028 \u2013 passing around 8 million kilometres from our planet. Astronomers will be ready to perform a wide raft of observations that will help us to understand the size and shape of the asteroid, as well as giving an incredibly accurate overview of where it will be in 2032.<\/p>\n

At the end of that encounter, we will know for sure whether there will be a collision in 2032. And if there is to be a collision that year, we\u2019ll be able to predict where on Earth that collision will be \u2013 likely to a precision of a few tens of kilometres.<\/p>\n

How big would the impact be?<\/h2>\n

At the moment, we don\u2019t know the exact size of 2024 YR4. Even through Earth\u2019s largest telescopes, it is just a single tiny speck in the sky. So we have to estimate its size based on its brightness. Depending on how reflective the asteroid is, current estimates place it as being somewhere between 40 and 100 metres across.<\/p>\n

What does that mean for a potential impact? Well, it would depend on exactly what the asteroid is made of.<\/p>\n

The most likely scenario is that the asteroid is a rocky pile of rubble. If that turns out to be the case, then the impact would be very similar to the Tunguska event in 1908.<\/p>\n

The asteroid would detonate in the atmosphere, with a shockwave blasting Earth\u2019s surface as a result. The Tunguska impact was a \u201ccity killer\u201d type event, levelling forest across a city-sized patch of land.<\/p>\n

<\/a>Meteor Crater in Arizona is believed to have been created by a 50m metallic meteorite impact around 50,000 years ago. NASA Earth Observatory \/ Wikimedia<\/a><\/p>\n

A less likely possibility is that the asteroid is made of metal. Based on its orbit around the Sun, this seems unlikely \u2013 but we can\u2019t rule it out.<\/p>\n

In that case, the asteroid would make it through the atmosphere intact, and crash into Earth\u2019s surface. If it hit on the land, it would carve out a new impact crater, probably more than a kilometre across and a couple of hundred metres deep \u2013 something similar to Meteor Crater in Arizona.<\/p>\n

Again, this would be quite spectacular for the region around the impact \u2013 but that would be about it.<\/p>\n

Living in a remarkable time<\/h2>\n

This all sounds like doom and gloom. After all, we know that the Earth will be hit again \u2013 either by 2024 YR4 or something else. But there\u2019s a real positive to take out of all this.<\/p>\n

There has been life on Earth for more than 3 billion years. In all that time, impacts have come along and caused destruction and devastation many times.<\/p>\n

But there has never been a species, to our knowledge, that understood the risk, could detect potential threats in advance, and even do something about the threat. Until now.<\/p>\n

In just the past few years, we have discovered 11 asteroids before they hit our planet. In each case, we have predicted where they would hit, and watched the results.<\/p>\n

We have also, in recent years, demonstrated a growing capacity to deflect potentially threatening asteroids. NASA\u2019s DART mission<\/a> (the Double Asteroid Redirection Test) was an astounding success.<\/p>\n

For the first time in more than 3 billion years of life on Earth, we can do something about the risk posed by rocks from space. So don\u2019t panic! But instead, sit back and watch the show.<\/p>\n

Jonti Horner<\/a>, Professor (Astrophysics), University of Southern Queensland<\/a><\/em><\/p>\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"

Jonti Horner, University of Southern Queensland On 27 December last year, astronomers using the ATLAS survey telescope in Chile discovered a small asteroid moving away from Earth. Follow up observations have revealed that the asteroid, 2024 YR4, is on a path that might lead to a collision with our planet on December 22 2032. In […]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-109607","post","type-post","status-publish","format-standard","hentry","category-uncategorized","entry"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/posts\/109607","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/comments?post=109607"}],"version-history":[{"count":0,"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/posts\/109607\/revisions"}],"wp:attachment":[{"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/media?parent=109607"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/categories?post=109607"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chezaspin.com\/blog\/wp-json\/wp\/v2\/tags?post=109607"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}