Planetary Defense (Against Asteroids)

[Trevp666]

Depends on the size of the target though I expect. I mean something miles across on a definite path to impact the earth will need a sizeable something to shift it's path by even a tiny amount.
The further away it is detected, the greater the chance, but still....
I mean if I saw a truck driving towards me, I doubt whether me throwing anything at it would make it stop.

 

[ramonmercado]

Not just space billiards, complex scenarios will be worked out.

On 26 September, an act of targeted violence will unfold 11 million kilometers from Earth, as a spacecraft about the size of a vending machine smashes into a small asteroid at 6 kilometers per second.

Unlike some asteroids that stray worrisomely close to Earth’s orbit, Dimorphos—the 160-meter moon of a larger body—is an innocent bystander, posing no threat to our world. But the looming assault represents humanity’s first-ever field test of a planetary defense mission: NASA’s Double Asteroid Redirection Test, or DART.

The hope is that the collision will nudge Dimorphos into a closer orbit around its 780-meter partner, Didymos, shortening its nearly 12-hour orbital period by a few minutes. A successful strike would support the idea that, in the future, similar efforts could deflect threatening asteroids onto safer courses. But new simulations and lab experiments show the fate of the mission depends heavily on a crucial question: Are such small asteroids solid boulders or—as astronomers increasingly believe—loose heaps of rubble?

The answer, which should be revealed from the crater and ejecta produced by DART’s collision, could determine just how hard to hit an asteroid when the exercise is not a test. “It’s going to be thrilling—and very stressful—but ultimately, I think we’re going to learn a lot,” says Cristina Thomas, a planetary scientist at Northern Arizona University who leads the observation team for the DART mission.

https://www.science.org/content/art...n-mission-more-billiards-space-scientists-say

 

[ramonmercado]

A trail of destruction.

A 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 picture of a comet-like plume spreading behind the giant rock. The probe was crashed last week to test whether asteroids that might threaten Earth can be nudged out of the way. Scientists are working to establish whether the test was a success, and the asteroid's trajectory altered.

The extraordinary image was taken two days after the collision by astronomers in Chile, who were able to capture the vast trail using the Southern Astrophysical Research Telescope (Soar). It stretches for more than 10,000km (6,200 miles), and is expected to get even longer until it disperses completely, and looks like other space dust floating around.

"It is amazing how clearly we were able to capture the structure and extent of the aftermath in the days following the impact," said Teddy Kareta, an astronomer involved in the observation.

https://www.bbc.com/news/science-environment-63140097

 

[Tunn11]

If the asteroid is a heap of rubble rather than a solid body as many seem to be, what effect will an impact have? I would have thought a solid body would react by changing course a bit but a rubble pile? It looks as if Dart may have knocked some debris off it so that if it were an Earth hitter it may give a prettier show when it hits.

 

[ramonmercado]

A trail of destruction.

A 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 picture of a comet-like plume spreading behind the giant rock. The probe was crashed last week to test whether asteroids that might threaten Earth can be nudged out of the way. Scientists are working to establish whether the test was a success, and the asteroid's trajectory altered.

The extraordinary image was taken two days after the collision by astronomers in Chile, who were able to capture the vast trail using the Southern Astrophysical Research Telescope (Soar). It stretches for more than 10,000km (6,200 miles), and is expected to get even longer until it disperses completely, and looks like other space dust floating around.

"It is amazing how clearly we were able to capture the structure and extent of the aftermath in the days following the impact," said Teddy Kareta, an astronomer involved in the observation.

https://www.bbc.com/news/science-environment-63140097

Really knocked it for six!

TWO WEEKS AGO, the asteroid Dimorphos was minding its own business, quietly orbiting around its partner Didymos, when suddenly NASA’s DART spacecraft plowed into it at 14,000 miles per hour.

The space agency and its partners planned that collision to see whether such an impact could alter an asteroid or comet’s trajectory—should humanity ever need to defend the planet from an oncoming space rock. Before the crash on September 26, Dimorphos circled its neighbor like clockwork: one lap every 11 hours and 55 minutes. If the DART test was successful, the proof would be a change in that orbital period, showing that the refrigerator-sized spacecraft had nudged the asteroid onto a different path.

Now the DART team has an answer: It worked—even better than expected. “For the first time ever, humanity has changed the orbit of a planetary body,” said Lori Glaze, director of the Planetary Science Division at NASA headquarters in Washington, at a press conference today revealing the result.

The team would have considered a 10-minute difference a success, said NASA chief Bill Nelson. But DART actually shortened the asteroid’s orbit by a whopping 32 minutes. Dimorphos now takes only about 11 hours and 23 minutes to circle its partner, he said—a significant change, meaning that it is indeed possible to deflect a small asteroid’s path. “NASA is serious about defending the planet,” he said.

https://www.wired.com/story/sucess-nasa-dart-clocks-dimorphos-asteroid/

 

[Mythopoeika]

I'm glad that they were able to demonstrate it working. What a relief.

 

[Kondoru]

Me too. Unlike the Dinosaura, we are safe.

(I mean, if anyone can be bothered).

 

[hunck]

Me too. Unlike the Dinosaura, we are safe.

(I mean, if anyone can be bothered).

The dinosaur-killing asteroid was way more massive than the object hit by the DART experiment, which I think would’ve had little to no effect on an asteroid that size.

It would take a much larger explosion to affect the trajectory of a massive object & hitting it a few years ahead of Earth impact could help.

 

[Mythopoeika]

The dinosaur-killing asteroid was way more massive than the object hit by the DART experiment, which I think would’ve had little to no effect on an asteroid that size.

It would take a much larger explosion to affect the trajectory of a massive object & hitting it a few years ahead of Earth impact could help.

We'd have had no chance with Oumuamua.
It entered the Solar System unexpectedly at great speed, then left pretty quickly. The elongated shape alone would make it hard to deflect.
Thankfully, it didn't take up an orbit round the Sun.

 

[maximus otter]

Experts on the Future of Planetary Defense 10 Years After the Chelyabinsk Asteroid Impact​

Coincidentally, negotiations sponsored by the United Nations were finalizing formal recommendations for the establishment of Planetary Defense-related international collaborations – the International Asteroid Warning Network (IAWN) and the Space Missions Planning Advisory Group (SMPAG) – when the Chelyabinsk impact occurred.

Asteroid “Chelyabinsk 2013” explodes over the city of Chelyabinsk, Russia on February 15, 2013. Credit: The Planetary Society/YouTube

Since then, NASA established the agency’s Planetary Defense Coordination Office (PDCO) in 2016 to oversee and coordinate the agency’s ongoing mission of Planetary Defense. This includes acting as a national representative at international Planetary Defense-related caucuses and forums, such as IAWN and SMPAG, and playing a leading role in coordinating U.S. government planning for response to an actual asteroid impact threat if one were ever discovered. The PDCO also funds observatories around the world through NASA’s Near-Earth Object (NEO) Observations Program to find and characterize NEOs – asteroids and comets that come within 30 million miles of Earth – with a particular focus on finding asteroids 460 feet (140 meters) and larger that represent the most severe impact risks to Earth.

To help accelerate its ability to find potentially hazardous NEOs, NASA is also actively developing the agency’s NEO Surveyor mission, which is designed to finish discovery of 90 percent of asteroids 140 meters in size or larger that can come near Earth within a decade of being launched.

In 2022, working together with the Italian Space Agency, NASA’s Double Asteroid Redirection Test (DART) mission successfully demonstrated the world’s first-ever test for deflecting an asteroid’s orbit. Launched in 2021, DART successfully collided with a known asteroid – which posed no impact threat to Earth – demonstrating one method of asteroid deflection technology using a kinetic impactor spacecraft. Since DART’s impact, Planetary Defense experts have been continuing to analyze data returned from the mission to better understand its demonstrated effects on the asteroid, which contributes to the understanding of how a kinetic impactor spacecraft could be used to address an asteroid impact threat in the future if the need ever arose.

“A collision of a NEO with Earth is the only natural disaster we now know how humanity could completely prevent,” said NASA Planetary Defense Officer Lindley Johnson. “We must keep searching for what we know is still out there, and we must continue to research and test Planetary Defense technologies and capabilities that could one day protect our planet’s inhabitants from a devastating event.”

https://scitechdaily.com/experts-on...binsk-asteroid-impacts-440-kiloton-explosion/

maximus otter

 

[ramonmercado]

Will we be able to deflect a Big One?

THE WOODLANDS, TEXAS—At a basic level, humanity’s survival odds come down to one thing: the chances of a giant space rock slamming into the planet and sending us the way of the dinosaurs. One way to calibrate that hazard is to look at the size of Earth’s recent large impact craters. And a provocative new study suggests they are bigger than previously thought—meaning Earth is more at risk of getting hit hard, says James Garvin, chief scientist of NASA’s Goddard Space Flight Center, who presented the work last week at the Lunar and Planetary Science Conference. “It would be in the range of serious crap happening.”

Using a new catalog of high-resolution satellite imagery, Garvin and his colleagues identified large rings around three impact craters and one probable one that are 1 million years old or younger. To Garvin, the rings imply the craters are tens of kilometers wider, and record far more violent events, than researchers had thought.

If Garvin is right—no sure bet—each impact resulted in an explosion some 10 times more violent than the largest nuclear bomb in history, enough to blow part of the planet’s atmosphere into space. Although not as destructive as the impact that killed off the dinosaurs, the strikes would have perturbed the global climate and caused local extinctions. ...

https://www.science.org/content/article/earth-higher-risk-big-asteroid-strike-satellite-data-suggest

 

[ramonmercado]

Really knocked it for six!

TWO WEEKS AGO, the asteroid Dimorphos was minding its own business, quietly orbiting around its partner Didymos, when suddenly NASA’s DART spacecraft plowed into it at 14,000 miles per hour.

The space agency and its partners planned that collision to see whether such an impact could alter an asteroid or comet’s trajectory—should humanity ever need to defend the planet from an oncoming space rock. Before the crash on September 26, Dimorphos circled its neighbor like clockwork: one lap every 11 hours and 55 minutes. If the DART test was successful, the proof would be a change in that orbital period, showing that the refrigerator-sized spacecraft had nudged the asteroid onto a different path.

Now the DART team has an answer: It worked—even better than expected. “For the first time ever, humanity has changed the orbit of a planetary body,” said Lori Glaze, director of the Planetary Science Division at NASA headquarters in Washington, at a press conference today revealing the result.

The team would have considered a 10-minute difference a success, said NASA chief Bill Nelson. But DART actually shortened the asteroid’s orbit by a whopping 32 minutes. Dimorphos now takes only about 11 hours and 23 minutes to circle its partner, he said—a significant change, meaning that it is indeed possible to deflect a small asteroid’s path. “NASA is serious about defending the planet,” he said.

https://www.wired.com/story/sucess-nasa-dart-clocks-dimorphos-asteroid/

Dimorphos' Orbital oddities observed, might be due to boulder swarm.

The asteroid Dimorphos is behaving in unexpected ways after being hit with a NASA rocket last year, new data suggest.

Recent observations of the roughly 580-foot-wide (177 meters) space rock — which NASA intentionally crashed a spaceship into on Sept. 26, 2022, as part of the Double Asteroid Redirection Test (DART) mission — show that Dimorphos may be tumbling in its normally steady orbit around its parent asteroid Didymos, according to New Scientist. Dimorphos also appeared to be continuously slowing down in its orbit for at least a month after the rocket impact, contrary to NASA's predictions.

California high school teacher Jonathan Swift and his students first detected these unexpected changes while observing Dimorphos with their school's 2.3-foot (0.7 meter) telescope last fall. Several weeks after the DART impact, NASA announced that Dimorphos had slowed in its orbit around Didymos by about 33 minutes. However, when Swift and his students studied Dimorphos one month after the impact, the asteroid seemed to have slowed by an additional minute — suggesting it had been slowing continuously since the collision.

https://www.livescience.com/space/a...ving-unexpectedly-high-school-class-discovers

 

[ramonmercado]

With the Sun in our eyes an asteroid might go down on us. There is scope for hope thoigh.

In the glare of the sun, an unknown number of near-Earth asteroids move on unseen orbits. A new generation of infrared telescopes could be our best defense against potential disaster.

Any asteroid larger than 165 feet (50 m) across is capable of breaching Earth's atmosphere and striking the ground. The sun's glare could be blinding us to thousands of them. (Image credit: Nicholas Forder)

On the morning of Feb. 15, 2013, a meteor the size of a semitrailer shot out from the direction of the rising sun and exploded in a fireball over the city of Chelyabinsk, Russia. Briefly glowing brighter than the sun itself, the meteor exploded with 30 times more energy than the bomb that destroyed Hiroshima, exploding some 14 miles (22 kilometers) above the ground. The blast shattered windows on more than 7,000 buildings, temporarily blinded pedestrians, inflicted instantaneous ultraviolet burns and otherwise injured more than 1,600 people. Fortunately, no known deaths resulted.

The Chelyabinsk meteor is thought to be the biggest natural space object to enter Earth's atmosphere in more than 100 years. Yet no observatory on Earth saw it coming. Arriving from the direction of the sun, the rock remained hidden in our biggest blind spot, until it was too late.

Events like these are, fortunately, uncommon. Rocks the size of the Chelyabinsk meteor — roughly 66 feet (20 meters) wide — breach Earth's atmosphere once every 50 to 100 years, according to an estimate from the European Space Agency (ESA). Larger asteroids strike even less frequently. To date, astronomers have mapped the orbits of more than 33,000 near-Earth asteroids and found that none pose a risk of hitting our planet for at least the next century.

But you can't calculate the risk of an asteroid you can't see — and there are untold thousands of them, including some large enough to destroy cities and potentially trigger mass-extinction events, moving on unknowable trajectories around our star, experts told Live Science. It's a harsh reality that has astronomers both concerned about the possible consequences and motivated to find as many of our solar system's hidden asteroids as possible. Once we know about them, deadly asteroids can either be monitored and deflected if needed, or if all else fails, populations can be warned to relocate to avoid mass casualties.

"The most problematic object is the one you don't know about," Amy Mainzer, a professor of planetary science at the University of Arizona and principal investigator for two NASA asteroid-hunting missions, told Live Science. "If we can know what's out there, then we can have a much better estimate of the true risk." ...

https://www.livescience.com/space/a...-can-scientists-spot-them-before-its-too-late

 

[ramonmercado]

At least NASA would warn us.

When the Chicxulub impactor, a six-mile-wide asteroid, struck Earth 66 million years ago, the dinosaurs had no warning.

If an asteroid that size hit Earth today, a shock wave two million times more powerful than a hydrogen bomb would flatten forests and trigger tsunamis. A seismic pulse equal to a magnitude 10 earthquake would crumble cities. And long after the impact, a cloud of hot dust, ash, and steam would blot out the sun, plunging the Earth into freezing cold.

But at least we'd probably know it was coming ahead of time. And if NASA has anything to say about it, we may even be able to prevent the apocalypse. NASA's Planetary Defense Coordination Office is tasked with finding, tracking, and assessing the risk associated with potentially hazardous asteroids in our solar system.

"We definitely want to find all those before they find us," said Lindley Johnson, Lead Program Executive for the Planetary Defense Coordination Office.

To do that, NASA works with a global coalition of astronomers called the International Asteroid Warning Network (IAWN). Here's what they would do if an apocalyptic asteroid strike was headed toward Earth. ...

https://www.sciencealert.com/nasa-reveals-how-it-would-warn-world-of-impending-asteroid-disaster