Massive asteroids can sneak up on Earth by appearing slower

Massive asteroids can sneak up on Earth by appearing slower - study

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Asteroids heading for Earth may have a small blind spot they can sneak through nearly completely undetected due to a slow speed, making it difficult for astronomers to spot them in time, according to a NASA-funded academic study.

The study in question, led by the University of Hawaii’s Prof. Richard Wainscoat, was published in the peer-reviewed academic journal Icarus

NASA and other space agencies and institutions around the world have created a vast network of telescopes and other monitoring systems to detect asteroids around space, specifically ones that approach the planet, which are known as Near-Earth Objects (NEOs). Most of these NEOs are asteroids, and the ones that approach very closely and have a diameter of at least 140 meters can often be declared potentially hazardous.

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Fortunately, due to technological advancements and the size of these asteroids, most of these asteroids are detected far in advance. But according to this study, there exists a “danger zone” of sorts that lets some asteroids essentially sneak up on the planet.

The gap in asteroid detection

When in this dangerous gap in our systems, the objects can slip past our detection systems and are only noticed right before or right after they pass the planet.

An asteroid is seen heading towards the planet in this artistic rendition. (credit: PIXABAY)

This study was prompted by one such incident in 2019.

On July 25, 2019, an asteroid known as 2019 OK skimmed past Earth at a distance of just around 70,000 kilometers. For comparison, the distance between the Earth and the Moon is just around 384,000 kilometers, making it a far closer brush.

This asteroid was around 100 meters in diameter, the largest known object to ever have such a close brush with Earth since the Tunguska impact incident in 1908, and thankfully did not impact the planet. But the worrying part is that scientists only noticed it around 24 hours before its close approach.

So how did the asteroids sneak up on us?

It should be noted that it is not unprecedented for asteroids to go undetected despite a close flyby being imminent. In fact, this is exactly what happened in 2013 during the last known significant asteroid impact.

At the time, the 17-meter asteroid exploded over the city of Chelyabinsk in Russia. The reason it had gone undetected is that it had approached Earth from the direction of the Sun, unlike other asteroids which approach Earth as they head towards the Sun. This is because the glare from the Sun makes it difficult to spot asteroids heading our way.

This is not an isolated incident either. In September, asteroid 2021 SG passed by the Earth and we didn’t even see it before it had already passed by at a very close distance.

But this is not the reason 2019 OK had gone undetected until 24 hours before its close flyby.

Rather, this was due to a combination of several factors, such as speed, timing and the Earth’s orbit.

To put it as simply as possible, 2019 OK seemed much slower than it actually was.

When an asteroid approaches the Earth from part of the eastern sky that, to oversimplify it, can be seen at a specific hour when looking up, the asteroid might appear stationary due to Earth’s orbit around the Sun and its own spin on its axis.

This phenomenon is what made it so hard to spot 2019 OK. In fact, if it hadn’t been for this, it could have been spotted around four weeks in advance.

It isn’t isolated either. According to the study, as many as 50% of asteroids heading from the east could experience this phenomenon too.

As such, it is imperative that scientists work hard to identify these slow-moving objects so we can be better prepared.

NASA develops countermeasures

Currently, NASA estimates that the Earth is free of asteroid impacts for the next century. However, scientists are well aware of the dangers of a possible impact event and have taken steps in this direction to not only catalog the many asteroids in the solar system but possibly find means of stopping these impacts.

The most promising of these methods is deflection, which would see a specially-designed spacecraft launched at an asteroid to slam into it, slightly altering its trajectory to avert an impact.

In layman’s terms: Punching it so it moves out of the way.

Don’t Look Up: Several Asteroids Are Heading Towards Earth – Dealing With Real-Life Threats to Our Planet

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Don’t look now – but we are currently experiencing a rash of stories about a forthcoming global catastrophe. But in a change from reports of pandemics and climate change, this global catastrophe is produced by the impact of a giant asteroid. Or comet. Or both. This may feel extra ominous given the events in the recent Netflix film “Don’t Look Up,” in which the Earth is threatened by a “planet killer” asteroid.

But how worried should we really be – and what would happen if such a body actually hit us?

It has been my experience that killer asteroids tend to strike in the summer months, when news is thin on the ground. Maybe we are so tired of grim news about the spread of the omicron COVID variant and associated problems that a killer asteroid (or comet) makes a refreshing change.

Some UK newspapers have turned to Nostradamus, the 16th century astrologer. A couple ran stories at the end of 2021 about 2022 being the year in which Nostradamus predicted that the world would end in a giant impact with a body from space. This hook has resulted in tabulations of objects that may (or, more likely, will not) come close to the Earth in 2022.

My favorite list was published by the Sun newspaper, which described five asteroids heading towards the Earth in January alone.

The scary headline and its accompanying image of an Earth in apparent danger is somewhat undermined by the sentences following the image, in which the newspaper states that “all of the forecasted asteroids this year will pass by Earth by a significant distance and is very unlikely they will hit our planet.” We have already missed (or been missed by) the first two asteroids in this list (2021 YQ and 2021 YX) which hurtled by Earth on January 5 at distances of 1.3 and 2.4 million miles, respectively.

No, I didn’t notice them either – and I study asteroids. There are a further three asteroids predicted to pass between 1 and 5 million miles from the Earth in the next few days, ranging in size from that of a car to that of the Statue of Liberty. The one that will get the closest will still be four times as far away as the Moon, so not exactly close calls.

Is ‘Don’t Look Up’ realistic?

Don’t Look Up is an allegory, using the globally catastrophic impact of a “planet killer” for the globally catastrophic impact of climate change. It is a tale of corruption, venality and political and corporate self-interest placed ahead of the health and welfare of humanity. It is also very funny.

Without giving away too many spoilers, the plot focuses around two astronomers (a graduate student and her professor) who discover a comet that will collide with Earth in six months’ time. They try to tell the President of the United States (played gloriously by Meryl Streep), but she is more concerned with the mid-term elections.

The film pokes fun at right-wing US politics, the influence of donations to political parties on policy (and politicians), the increasing capacity for modern technology to collect information about health, habits, and lifestyle and the use of that information by technology giants.

It does not poke fun at the science though: the discovery of the comet is (sort of) realistic. Which is as it should be, since Amy Mainzer, Principal Investigator of NASA’s NEOWISE asteroid tracking program, was scientific advisor to the production. In the film, the astronomers report their findings to the Planetary Defense Coordination Office, which, as the movie shows, is a real organization operated by NASA.

So is the film realistic? The Earth has been hit by large asteroids in the past – which is why there are no enormous dinosaurs roaming the planet today. And it is bombarded every day by tonnes of dust and meteorites. It is certain that a “planet killer” is written in the future (though occurring at most once in 50 million years) – and this is taken much more seriously by international governments than is shown in the film.

There is a well-tested protocol for reporting new asteroids and comets, which is how we know about the ones passing close(ish) to Earth this month.

There are also plans to mitigate the potential consequences from an asteroid on collision course with the Earth. These typically rely on deflecting the asteroid’s course, as trying to shoot it down last minute isn’t feasible – it would take too much energy. The launch in November of NASA’s DART mission, a technology-testing mission, will further help shed light on how to best deflect asteroids threatening Earth.

But where Don’t Look Up touches a nerve is the lack of preparedness for the emergency if (when) it finally happens and the mitigation plans have failed. Here I come back to the allegory for climate change. There is no Plan B. In the film, the slogan ‘Don’t Look Up’ is a denial that an approaching comet will destroy the planet – it is portrayed as fake news.

I thought it was a great film. It is entertainment. But it is not fake news. We are a global community and we must act together.

Written by Monica Grady, Professor of Planetary and Space Sciences, The Open University.

This article was first published in The Conversation.

Netflix’s best apocalypse movie reveals the truth about planet-killing asteroids

]

Don’t look now — but we are currently experiencing a rash of stories about a forthcoming global catastrophe. But in a change from reports of pandemics and climate change, this global catastrophe is produced by the impact of a giant asteroid. Or comet. Or both.

This may feel extra ominous given the events in the recent Netflix film Don’t Look Up, in which the Earth is threatened by a “planet killer” asteroid.

But how worried should we really be — and what would happen if such a body actually hit us?

It has been my experience that killer asteroids tend to strike in the summer months when news is thin on the ground. Maybe we are so tired of grim news about the spread of the omicron Covid variant and associated problems that a killer asteroid (or comet) makes a refreshing change.

Some U.K. newspapers have turned to Nostradamus, the 16th-century astrologer. A couple ran stories at the end of 2021 about 2022 being the year in which Nostradamus predicted that the world would end in a giant impact with a body from space. This hook has resulted in tabulations of objects that may (or, more likely, will not) come close to the Earth in 2022.

My favorite list was published by the Sun newspaper, which described five asteroids heading towards the Earth in January alone.

The scary headline and its accompanying image of an Earth in apparent danger are somewhat undermined by the sentences following the image, in which the newspaper states that “all of the forecasted asteroids this year will pass by Earth by a significant distance and is very unlikely they will hit our planet”.

We have already missed (or been missed by) the first two asteroids in this list (2021 YQ and 2021 YX) which hurtled by Earth on January 5 at distances of 1.3 and 2.4 million miles, respectively.

Barringer Crater aerial photo. USGS/wikimedia

No, I didn’t notice them either — and I study asteroids. There are a further three asteroids predicted to pass between one and five million miles from the Earth in the next few days, ranging in size from that of a car to that of the Statue of Liberty. The one that will get the closest will still be four times as far away as the Moon, so not exactly close calls.

Is Don’t Look Up realistic?

Without giving away too many spoilers, the plot focuses on two astronomers (a graduate student and her professor) who discover a comet that will collide with Earth in six months’ time. They try to tell the president of the United States (played gloriously by Meryl Streep), but she is more concerned with the midterm elections.

The film pokes fun at right-wing U.S. politics, the influence of donations to political parties on policy (and politicians), the increasing capacity for modern technology to collect information about health, habits, and lifestyle, and the use of that information by technology giants.

It does not poke fun at the science, though: the discovery of the comet is (sort of) realistic. This is as it should be, since Amy Mainzer, principal investigator of NASA’s NEOWISE asteroid tracking program, was a scientific advisor to the production.

In the film, the astronomers report their findings to the Planetary Defense Coordination Office, which, as the movie shows, is a real organization operated by NASA.

So is the film realistic? The Earth has been hit by large asteroids in the past — which is why there are no enormous dinosaurs roaming the planet today. And it is bombarded every day by tonnes of dust and meteorites.

It is certain that a “planet killer” is written in the future (though occurring at most once in 50 million years) — and this is taken much more seriously by international governments than is shown in the film.

There is a well-tested protocol for reporting new asteroids and comets, which is how we know about the ones passing close(ish) to Earth this month.

There are also plans to mitigate the potential consequences of an asteroid on a collision course with the Earth. These typically rely on deflecting the asteroid’s course, as trying to shoot it down last minute isn’t feasible — it would take too much energy. The launch in November of NASA’s DART mission, a technology-testing mission, will further help shed light on how to best deflect asteroids threatening Earth.

But where Don’t Look Up touches a nerve is the lack of preparedness for the emergency if (when) it finally happens and the mitigation plans have failed. Here I come back to the allegory for climate change. There is no Plan B. In the film, the slogan “Don’t Look Up” is a denial that an approaching comet will destroy the planet — it is portrayed as fake news.

I thought it was a great film. It is entertainment. But it is not fake news. We are a global community, and we must act together.

This article was originally published on The Conversation by Monica Grady at The Open University. Read the original article here.

Thousands of Asteroids Orbit Near Earth. NASA’s Next-Gen Spotter Helps Protect Us

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For example, it could not account for changes in an asteroid’s trajectory from influences such as heating effects by sunlight; these are nongravitational influences that cause small but constant deviations.

Sentry I also had difficulty plotting how much the course of an object would deviate when it swung close to Earth and our planet’s gravity.

Like a Gen-Z youngster with technical savvy that puts older generations to shame, Sentry II takes these influences into account with finesse, coming swiftly to more accurate projections and predictions. This high-powered mission is well equipped to take on the rising tide of orbital data flooding in from around the world.

Near-Earth asteroids

Since the first asteroid was discovered on New Year’s Day in 1801, generations of astronomers have found many, many more space rocks lurking in the dark.

Over the last two centuries, larger and more sensitive telescopes, and more recently spacecraft, have probed for the faint, elusive dots of light crawling against the starry backdrop of space. In the last few decades, our awareness of them has risen exponentially.

To date, astronomers know of more than 27,000 near-Earth asteroids, and discover about 3,000 more every year. Of these, 9,948 are larger than 460 feet across, and 889 are larger than a half mile in diameter, large enough to inflict regional or global devastation should they impact our planet — so the importance of tracking their orbital motions and projecting their paths into the future is plain.

Asteroids that cross Earth’s orbit and present the possibility of collision are, obviously, the ones to keep the closest eye on. Those larger than 460 feet (about the length of one-and-a-half football fields) are considered potentially hazardous objects — the cars on the freeway that can make your heart jump.

What would happen if an asteroid hit Earth?

It’s happened before: a major asteroid or comet impact with Earth. Sixty-six million years ago, a 6-mile-wide asteroid hit the northern top of the Yucatan Peninsula and wrought global devastation that contributed to the extinction of the dinosaurs, along with 75% of all species living at the time.

On average, an impact on the scale of the dinosaur-killer happens about every 100 million years. The good news is, pretty much all asteroids even approaching that size have been found and their orbits mapped out very accurately, and none of them is projected to come near Earth. Their orbits are fairly stable and can be accurately predicted far into the future.

But smaller asteroids are another matter. Their orbits are more strongly influenced by gravitational interactions with planets and other effects, which complicates predictions of their future whereabouts. They’re also harder to detect, so there are many yet unknown.

Smaller asteroids also are more numerous, and they both pass near and impact Earth more frequently.

In 1908, a collision by a large object caused an aerial explosion over Siberia that flattened forests for miles around and sent tremors through Earth that were detected by seismographs in London.

In 2013, a 20-meter object exploded in Earth’s atmosphere above the Russian city of Chelyabinsk. The shockwave shattered windows and caused some brick structures to collapse, and though there were no fatalities, over 1,400 people were injured by indirect causes.

Smaller chunks of rock burn up in Earth’s atmosphere or hit the ground on a daily basis, and though their effects may be minor, they usually go undetected until only hours before impact, if at all, coming at us with little or no advance warning.

Like a fender bender in traffic, even the smallest meteorite impact could spoil someone’s day, or worse, so keeping tabs on the traffic around Earth is important. Knowing what’s coming at you is the first step in predicting, and possibly avoiding, a collision.

Earth ‘could be SAVED with far-fetched plot to push us away from Sun using asteroids’, scientist claims

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HUMANITY could be saved from rising global temperatures by altering Earth’s orbit using space rocks.

That’s according to one bonkers scientist, who has controversially claimed that asteroids adorned with enormous, high-tech sails are the solution to our climate woes.

Dr Sohrab Rahvar, an astrophysicist at the Sharif University of Technology in Iran, outlined his hypothetical ploy in a paper published online on Tuesday.

He told The Sun that the scheme would involve pushing Earth’s orbit away from the Sun in a game of “gravitational billiards”.

By directing objects from the asteroid belt into near-misses with our planet, he claimed, scientists could nudge us thousands of miles further from our star.

This would serve to cool global temperatures which – alongside the reduction of greenhouse gas emissions – would mitigate the effects of global heating.

The proposal, which would take decades to complete, has sparked controversy among scientists, one of whom described it as “bonkers”.

It would be astronomically expensive to pull off with no guarantee of working, and if it were to go wrong would pose a serious threat to life on Earth.

The plan also relies on solar sails, a hypothetical type of high-powered propulsion technology that has not yet been invented.

SPACE BILLIARDS

Dr Rahvar’s strategy relies on a technique known as a “gravity assist”.

It’s an approach used by space agencies to accelerate a spacecraft or redirect its path by flying it close to a planet or other space object.

According to Dr Rahvar, under certain circumstances, such close passes can ever-so-slightly change the orbit of the object providing the “assist”.

He proposes strapping solar sails – high-tech reflective sheets propelled by the sun’s radiation – to space rocks in the asteroid belt.

These can then be sent in the direction of Earth to perform close passes with Earth that gradually change our planet’s orbit.

“We need a series of asteroids to [pass close to] Earth to have effective temperature loss,” Dr Rahvar told The Sun.

“For instance, in order to decrease the Earth’s temperature to one degree, we need to move it away from the sun in the order of 150,000 miles.”

He added: “The result would be a fainter sun in the sky and a decrease in the Earth’s temperature.”

ROCKY HORROR

According to the physicist’s calculations, it would take upwards of 70 years to complete the hair-brained project.

In the meantime, engineers need to invent a working solar sail that can travel into the deep reaches of space.

Scientists have discussed the possibilities of the technology for decades, but a working prototype remains a long way off.

Dr Rahvar said he hadn’t estimated the cost of the project. It would likely reach the tens of billions of dollars.

He stressed that the cheapest and most effective way to halt global temperature rises is by reducing greenhouse gas emissions.

“The cheapest way to get rid of global warming is the decarbonization of the atmosphere,” he told The Sun.

“However, advanced future civilizations on the earth will definitely have the capacity to carry out the project that I propose here.”

The research was published in the pre-print journal Arxiv. It has not yet been peer-reviewed by scientists.

‘LOOKS DODGY’

Experts reacted to Dr Rahvar’s paper with a mixture of confusion and scorn.

Dr Jonathan McDowell, a researcher at the Harvard–Smithsonian Center for Astrophysics, said the proposal risked flinging a space rock straight into Earth.

He told The Sun: “I haven’t worked through the maths in detail but some of it looks dodgy.

“He also completely fails to follow through with discussing the implications of his results.

“Even if you assume his results are right, they imply that to fix global warming this way you would need to put hundred-square-kilometre sails on each of about a hundred million asteroids and wait a century, with a significant risk of putting one or more of these asteroids accidentally on a collision course with Earth – if not on the first pass, then on subsequent orbits.

“So another way of summarizing his paper is: No, you can’t fix global warming this way.”

His comments were echoed by Professor Brad Gibson, an astrophysicist at the University of Hull, who described the plan as “not feasible today in the slightest”.

2 The proposal has sparked controversy among scientists Credit: Getty

Meet the man with an observatory on a Welsh hilltop who tracks thousands of potentially apocalyptic asteroids for Nasa

In other news, personalised smart guns, which can be fired only by verified users, may finally become available to U.S. consumers this year.

Scientists are embarking on a mission to unravel the mystery behind dozens of grisly child mummies buried in an underground tomb in Sicily.

Police have caught an Italian mafia henchman who’d be on the run for 20 years after spotting the fugitive on Google Maps.

And, one of the best-preserved fossils ever found has confirmed that young dinosaurs burst from their shells just like baby birds.

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