A newly discovered asteroid has climbed to the top of NASA’s impact risk list after fresh observations doubled its chances of striking Earth in 2032. Recent images captured by the Gemini South Telescope in Chile provide a detailed look at YR4 2024, which measures between 131 and 295 feet wide – roughly the size of a building – large enough to potentially unleash devastating consequences if it were to make contact. With a 1-in-48 collision probability, scientists are closely tracking the space rock, now called “city-killer.”

Though the rising impact risk might seem alarming, scientists explain that it’s a normal part of refining YR4’s orbit. NASA’s Near Earth Objects Studies has been tracking the asteroid closely since its discovery by the NASA-funded ATLAS system on December 27, 2024.

NASA astronomer Bryce Bolin, involved in the photo-op, described the discovery as both a concern and a scientific opportunity. “Only a few asteroids have been studied like this,” he told Space.com. “We took 12 200-second long exposures in the Red band and tracked the motion of the asteroid to obtain these images.”

At the time of the observation, YR4 was about 59 million km from Earth, and the team had to contend with several challenges. The asteroid was so faint that scientists had to use the massive Gemini South telescope in Chile to spot it.

The bright moon, which was 70 per cent illuminated, made it even harder to capture a clear image. Mr Bolin also said that the asteroid was also moving quickly at 0.26 arcseconds per minute, requiring careful tracking to keep it in view.

Experts are also focused on the scientific opportunity that YR4 presents. Mr Bolin said the YR4 was “extremely exciting… for the scientific potential of studying such a small asteroid in high detail.”

NASA’s James Webb Space Telescope is also set to assist with observing YR4, with data collection beginning in early March. Using its advanced infrared instruments, Webb will help astronomers more accurately measure the size of the asteroid and assess the potential impact damage if it were to collide with Earth.

While scientists are still studying the asteroid’s path, a collision could be devastating, releasing energy equal to 8 megatons of TNT – enough to destroy an area the size of Washington, DC.

Asteroid expert David Rankin, who has been tracking YR4, reassured the public that the rising impact odds are expected. He said that the risk will likely decrease once scientists gather more precise data on the asteroid’s orbit.

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 other words, the newly-discovered space rock poses a significant impact threat to our planet.

It sounds like something from a bad Hollywood movie. But in reality, there’s no need to panic – this is just another day living on a target in a celestial shooting gallery.

So what’s the story? What do we know about 2024 YR4? And what would happen if it did collide with Earth?

A target in the celestial shooting gallery

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.

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 – so impacts from objects that could imperil life on Earth’s surface are much less frequent.

The most famous impact came some 66 million years ago. A giant rock from space, at least 10 kilometres in diameter, crashed into Earth – causing a mass extinction that wiped out something like 75% of all species on Earth.

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.

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 – all pointing inwards towards the epicentre of the explosion.

In total, the Tunguska event levelled an area of almost 2,200 square kilometres – 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.

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’t know – but that’s part of the fun of science.

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.

The explosion, about 30 kilometres above the Earth’s surface, generated a powerful shock-wave and extremely bright flash of light. Buildings were damaged, windows smashed, and almost 1,500 people were injured – although there were no fatalities.

It served as a reminder, however, that Earth will be hit again. It’s only a question of when.

Which brings us to our latest contender – asteroid 2024 YR4.

The 1-in-77 chance of collision to watch

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’s largest telescopes.

The observations carried out over the past month have allowed astronomers to extrapolate the asteroid’s 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 – and may even collide with us.

At present, our best models of the asteroid’s 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.

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.

When will we know for sure?

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

But it is unlikely we’ll be able to say for sure whether we’re in the clear at that point.

Fortunately, the asteroid will make another close approach to the Earth in December 2028 – 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.

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’ll be able to predict where on Earth that collision will be – likely to a precision of a few tens of kilometres.

How big would the impact be?

At the moment, we don’t know the exact size of 2024 YR4. Even through Earth’s 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.

What does that mean for a potential impact? Well, it would depend on exactly what the asteroid is made of.

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.

The asteroid would detonate in the atmosphere, with a shockwave blasting Earth’s surface as a result. The Tunguska impact was a “city killer” type event, levelling forest across a city-sized patch of land.

A less likely possibility is that the asteroid is made of metal. Based on its orbit around the Sun, this seems unlikely – but we can’t rule it out.

In that case, the asteroid would make it through the atmosphere intact, and crash into Earth’s 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 – something similar to Meteor Crater in Arizona.

Again, this would be quite spectacular for the region around the impact – but that would be about it.

Living in a remarkable time

This all sounds like doom and gloom. After all, we know that the Earth will be hit again – either by 2024 YR4 or something else. But there’s a real positive to take out of all this.

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.

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.

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.

We have also, in recent years, demonstrated a growing capacity to deflect potentially threatening asteroids. NASA’s DART mission (the Double Asteroid Redirection Test) was an astounding success.

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’t panic! But instead, sit back and watch the show.

Jonti Horner is a Professor of Astrophysics, University of Southern Queensland. This article is republished from The Conversation.

Comets may have been responsible for the presence of water on Earth, scientists have claimed, according to a new research published this week in Science Advances. The researchers focused on Comet 67P/Churyumov-Gerasimenko and discovered that the molecular structure of water found on the celestial body closely resembled that of Earth’s oceans. While water existed in the gas and dust form when Earth formed around 4.6 billion years ago, questions regarding how it ultimately became rich in liquid water have puzzled scientists.

Researchers are of the view that a substantial portion of our oceans came from the ice and minerals on asteroids and possibly comets that crashed into Earth. To further their theory, the researchers led by Kathleen Mandt, a planetary scientist at NASA’s Goddard Space Flight Center, decided to use an advanced statistical computation technique to find the molecular structure of water on 67P which belongs to the Jupiter family of comets, using data captured by European Space Agency’s (ESA) Rosetta mission to the asteroid.

Also Read | Mysterious ‘Dark Comets’ May Pose Bigger Threat Than Previously Thought To Earth

Earth’s specific signature

The water on Earth has a unique molecular signature which has to do with specific rations of the hydrogen variant, or isotope, called deuterium. For the last few decades, deuterium levels in water found in the vapour trails of several Jupiter-family comets displayed similar levels to that of Earth’s water.

“So I was just curious if we could find evidence for that happening at 67P. And this is just one of those very rare cases where you propose a hypothesis and actually find it happening,” said Ms Mandt.

As it turned out, Ms Mandt’s team found a clear connection between deuterium measurements in the comet and the amount of dust around the Rosetta spacecraft.

“As a comet moves in its orbit closer to the Sun, its surface warms up, causing gas to release from the surface, including dust with bits of water ice on it. Water with deuterium sticks to dust grains more readily than regular water does,” the study highlighted.

“When the ice on these dust grains is released into the coma, this effect could make the comet appear to have more deuterium than it has,” it added.

The research has big implications not only for understanding comets’ role in delivering Earth’s water but also for understanding comet observations that provide insight into the formation of the early solar system.

Asteroid collisions with Earth are surprisingly common, with NASA estimating 48.5 tonnes of meteoric material entering our atmosphere daily. Most burn up, producing shooting stars. Although devastating asteroid impacts are rare in Earth’s history, humanity has learned a crucial lesson from the catastrophic event 66 million years ago. The asteroid responsible for the dinosaurs’ extinction was approximately six miles wide, but significantly smaller objects still pose a significant threat. In the face of potentially catastrophic asteroid impacts, scientists are racing to develop innovative solutions to protect our planet. 

In New Mexico, scientists are exploring a futuristic solution to defend Earth against asteroid threats: harnessing X-ray blasts from nuclear explosions, the Guardian reported. Scientists at Sandia National Laboratories in Albuquerque have successfully demonstrated a revolutionary method to deflect incoming asteroids using nuclear explosions. For the experiment, researchers harnessed the power of X-rays from a nuclear blast to vaporise the surface of a nearby asteroid.

The process works by unleashing an immense pulse of radiation, heating the asteroid’s surface to tens of thousands of degrees. This creates a rapidly expanding ball of gas that can nudge the asteroid off its catastrophic course. By precisely calculating the blast’s impact, scientists believe this technique can effectively push threatening asteroids away from Earth, potentially saving humanity from doomsday. 

“The primary mechanism involves using X-rays to rapidly heat the target surface, causing it to vaporize and expand into the adjacent vacuum. The expanding gas pushes against the asteroid, transferring momentum (in the opposite direction),” authors of the study published Monday in the journal Nature Physics wrote. 

Scientists noted that the nuclear option is for larger asteroids, particularly when time is short. Researchers believe this strategy can effectively deflect asteroids up to 2.5 miles wide, although this isn’t a rigid limit.

“If there is enough warning time, one can certainly deflect larger asteroids,”  Dr Nathan Moore, the first author of the study said. 

Mr Moore and his team plan to conduct further experimental tests to refine the X-ray deflection technique, building on their initial success. Their goal is to enhance the method’s effectiveness through additional laboratory experiments. Ultimately, they envision a space-based demonstration, similar to NASA’s DART (Double Asteroid Redirection Test) mission, to test the technique on a real asteroid. 

Officials at NASA confirmed today that a 120-foot asteroid, roughly the size of a small aeroplane, will make a close approach to Earth. But do not worry, as despite close proximity, the asteroid 2022 SW3 poses no threat. NASA’s Jet Propulsion Laboratory assured there was no cause for concern when it said that the asteroid “is going to come no closer than about 1.6 million miles.”

It will pass within the distance of three times that of Earth to the Moon. Although close, the scientists are swift to say that it does not threaten Earth yet. This close encounter will be an opportunity for scientists to acquire much-needed data about near-earth objects (NEOs).

The scientists track the orbits of the known asteroids, including 2022 SW3, which periodically come close to the Earth orbit. These observations are very important for the purpose of prediction and assessing danger.

Indeed, asteroids were part of the material leftovers of the old solar system, born about 4.6 billion years ago. They don’t have atmospheres and are not shaped as planets. High technology and observation can trace their paths to the smallest detail.

A few had major implications for Earth, including the one at Chicxulub that caused the demise of the dinosaurs 66 million years ago.

Examples include NASA’s OSIRIS-REx and Japan’s Hayabusa2. Samples obtained from missions like these have been instrumental in giving answers about the origin of our solar system and how life-preserving compounds could have landed on Earth. Every asteroid that passes adds to our chances of getting ready for other potential threats.

Today’s close flyby also becomes an eye-opener to the fact that one cannot just understand asteroids or close observations of them once and for all. Though this event is not hazardous, it will be a good time to collect data in preparation for upcoming encounters by scientists.

The space agency NASA has created a defence system to ward off the fear of these near-earth objects. According to NASA, the Double Asteroid Redirection Test (DART), the world’s first planetary defence technology demonstration, successfully impacted its asteroid target in the past in an attempt to move an asteroid in space.

Perth, Australia:

NASA’s DART mission – Double Asteroid Redirection Test – was humanity’s first real-world planetary defence mission.

In September 2022, the DART spacecraft smashed into the companion “moon” of a small asteroid 11 million kilometres from Earth. One goal was to find out if we can give such things a shove if one were headed our way.

By gathering lots of data on approach and after the impact, we would also get a better idea of what we’d be in for if such an asteroid were to hit Earth.

Five new studies published in Nature Communications today have used the images sent back from DART and its travel buddy LICIACube to unravel the origins of the Didymos-Dimorphos dual asteroid system. They’ve also put that data in context for other asteroids out there.

Asteroids are natural hazards

Our Solar System is full of small asteroids – debris that never made it into planets. Those that come close to Earth’s orbit around the Sun are called Near Earth Objects (NEOs). These pose the biggest risk to us, but are also the most accessible.

Planetary defence from these natural hazards really depends on knowing their composition – not just what they’re made of, but how they’re put together. Are they solid objects that will punch through our atmosphere if given the chance, or are they more like rubble piles, barely held together?

The Didymos asteroid, and its tiny moon Dimorphos, are what’s known as a binary asteroid system. They were the perfect target for the DART mission, because the effects of the impact could be easily measured in changes to Dimorphos’ orbit.

They are also close(ish) to Earth, or are at least NEOs. And they’re a very common type of asteroid we haven’t had a good look at before. The chance to also learn how binary asteroids form was the icing on the cake.

Quite a few binary asteroid systems have been discovered, but planetary scientists don’t exactly know how they form. In one of the new studies, a team led by Olivier Barnouin from Johns Hopkins University in the United States used images from DART and LICIACube to estimate the age of the system by looking at surface roughness and crater records.

They found Didymos is roughly 12.5 million years old, while its moon Dimorphos formed less than 300,000 years ago. That may still sound like a lot, but it’s much younger than was expected.

A pile of boulders

Dimorphos is also not a solid rock as we’d typically imagine. It is a rubble pile of boulders that are barely held together. Along with its young age, it shows there can be multiple “generations” of these rubble pile asteroids in the wake of larger asteroid collisions.

Sunlight actually causes small bodies like asteroids to spin. As Didymos started to spin like a top, its shape became squashed and bulged in the middle. This was enough to cause large pieces to just roll off the main body, with some even leaving tracks.

These pieces slowly created a ring of debris around Didymos. Over time, as the debris started sticking together, it formed the smaller moon Dimorphos.

Another study, led by Maurizio Pajola from Auburn University in the US used boulder distributions to confirm this. The team also discovered there were significantly more (up to five times) large boulders than have been observed on other non-binary asteroids humans have visited.

Another of the new studies shows us that boulders on all asteroids space missions have visited so far (Itokawa, Ryugu and Bennu) were likely shaped the same way. But this excess of larger boulders on the Didymos system could be a unique feature of binaries.

Lastly, another paper shows this type of asteroid appears to be more susceptible to cracking. This happens due to the heating–cooling cycles between day and night: like a freeze–thaw cycle but without the water.

This means if something (such as a spacecraft) were to impact it, there would be much more debris thrown up into space. It would even increase the amount of “shove” it could have. But there is a good chance that what lies underneath is much stronger than what we’re seeing on the surface.

This is where the European Space Agency’s Hera mission will step in. It will not only be able to provide higher-resolution images of the DART impact sites, but will also be able to probe the asteroids’ interiors using low-frequency radar.

The DART mission not only tested our ability to protect ourselves from future asteroid impacts, but also enlightened us on the formation and evolution of rubble pile and binary asteroids near Earth.

(Author:Eleanor K. Sansom, Research Associate, Curtin University)

(Disclosure Statement:Eleanor K. Sansom receives funding from the International Centre for Radio Astronomy Research and is supported by the Australian Research Council)

This article is republished from The Conversation under a Creative Commons license. Read the original article.
 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)