Replies to This Discussion

Permalink Reply by Dr. Krishna Kumari Challa on March 4, 2014 at 8:18am

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https://b612foundation.org/

The B612 Foundation – an organization devoted to the monitoring and mitigation of harmful asteroid impacts on Earth

https://b612foundation.org/list-of-impacts-from-impact-video/

http://www.telegraph.co.uk/news/science/space/11283886/Mountain-siz...

Mountain-sized asteroid is heading towards Earth, says scientist

A Russian scientist has discovered a huge asteroid '2014 UR116' passes Earth every three years

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https://www.rt.com/news/329211-russia-europe-space-defense/

Russian researchers plan nuking asteroids for EU defense project to avoid fate of Dinos

How can Earth be protected from dangerous asteroids? The EU’s international NEOShield project posed this question to Russian researchers, who say, as a first line of defense, space-borne nuke warheads would do the job perfectly.

Russian scientists believe that, at the present time, a nuclear explosion set off close to a dangerous asteroid remains the most effective means to change its trajectory, and thus escape the impact, TASS news agency reported on Saturday.

Although international space treaties in force prohibit nuclear weapons in space at present, if an asteroid posed a real threat to life on our planet, “such bans are naturally going to be dropped,” Russia’s International Scientific Community Central Engineering Research Institute (TsNIIMash) told the agency.

Researchers stressed that the safest way to influence an asteroid’s orbit is in outer space, a good deal prior to the space wanderer’s expected collision with Earth.

“In this case a nuclear blast is conducted in such a way that the asteroid does not disintegrate into smaller pieces,” explain Russian space experts. The explosion would force the ejection of material from the space body’s surface, creating sufficient thrust to affect the its trajectory and sidetrack it to a safe orbit.

NEOShield is an international consortium that addresses the threat of impacts to Earth, hoping to avert the fate of the dinosaurs. Largely funded by the European Commission, it has gathered researchers from Germany, France, Britain, Spain, Russia, and the US.

The project’s primary aim is to investigate in detail the three most promising asteroid threat-reduction techniques: kinetic impactors, gravity tractors, and the explosive blast-deflection method.

TsNIIMash has been participating in NEOShield’s project. The institute is a part of Russia’s Roskosmos space agency specializing in the development of intercontinental ballistic missiles, air defense missiles, and their propulsion units.

Russia’s 2016-2025 federal space program includes a measure establishing a national space center dedicated to detecting potential threats from asteroids and comets.

Four Nebosvod-S (Welkin) satellites will be commissioned to monitor near-Earth space threats. Two of them will be planetary sentries on a circumterrestrial orbit and two others will be delivered to Earth’s circumsolar orbit.

The satellites will be capable of spotting space objects measuring several meters across.

NASA has been running the Near Earth Objects (NEO) program, which identifies and monitors asteroids, comets, and large space rock fragments that could be potentially dangerous to Earth, since 1998. As of September 2014, it had identified more than 11,000 objects bigger than 140 meters across, which only amounts to about 10 percent of NASA’s stated goal: to catalogue 90 percent of all near-Earth objects by 2020.

In December of 2015, Russia’s Emergency Ministry reported that there will be 11 occasions when large asteroids come in hazardous proximity to Earth within the next 35 years.

The earliest one is expected on October 12, 2017, when asteroid 2012 TC4, estimated to be 17 meters in diameter, will shoot past Earth within the Moon’s orbit, missing our planet by a mere 115,000 kilometers – which is less than a third of the distance from Earth to the Moon (385,000 kilometers).

Permalink Reply by Dr. Krishna Kumari Challa on August 19, 2014 at 9:17am

Asteroid 1950 DA is heading towards Earth at a very fast rate and the collision might end the life on the planet, it has been reported.

Asteroid which has 1,000 metres in diameter could 'smash' into the planet at nearly 40,000 miles per hour, which could cause an explosion of unprecedented proportions, triggering huge tsunamis capable of covering entire cities, the Daily Star reported.

NASA classes any asteroid with a diameter of over 50 metres as a potential "city-killer". The rock has been hurtling through space so fast that it has experienced "negative gravity".

Alarmingly the rock has a 300/1 chance of striking Earth with the current predicted impact placed at March 16, 2880. Around 66m years ago a giant asteroid crashed down in Mexico, wiping out the last of the dinosaurs as well as most of the planet's plant life.
-NASA

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NASA to Send Sample-Return Mission to Earth-Bound Asteroid

A spacecraft set to launch in 2016 will head for a carbonaceous asteroid that has a high probability of colliding with Earth in the 22nd century

The asteroid-return mission qualifies as sophisticated exploration, building on the U.S. space agency’s wildly successful two-decade run of robotic missions to Jupiter, Saturn and the terrestrial planets. But Japan’s space agency JAXA already won the race to take home an asteroid sample. Hayabusa looked like a jinxed mission at several junctures with fuel, communications and engine troubles. But once it successfully dropped its collection canister in the Australian desert, a last-ditch dental-style scraping in 2010 yielded miniscule amounts of dust taken from the miniature asteroid Itokawa. JAXA might even beat the U.S. to a second sample return as its Hayabusa 2 mission is in the works.

Planetary scientists study asteroids (and meteorites, which is the term for asteroids and comet pieces that have fallen to Earth) because they are rocks left over from the formation of the solar system’s planets and can carry complex organic molecules. A great number of these fascinating time capsules also could strike and seriously damage Earth and its environment.

http://www.scientificamerican.com/article/nasa-to-send-sample-retur...

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NASA will tackle asteroids with new Planetary Defense Office

We can all sleep more soundly tonight - NASA has opened a new office to track asteroids and comets that come too close to Earth.

The Planetary Defense Coordination Office (PDCO) formalizes the agency’s existing program for detecting and tracking near-Earth Objects (NEOs). The office is located within NASA’s Planetary Science Division, which is in the agency's Science Mission Directorate in Washington.

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Related: NASA nixes asteroid threat rumor

“The office will be responsible for supervision of all NASA-funded projects to find and characterize asteroids and comets that pass near Earth's orbit around the sun,” said NASA, in a statement. “It will also take a leading role in coordinating interagency and intergovernmental efforts in response to any potential impact threats.”

The space agency explained that more than 13,500 near-Earth objects have been discovered to date – more than 95 percent of them since NASA-funded surveys began in 1998. About 1,500 NEOs are now detected each year, according to NASA.

"Asteroid detection, tracking and defense of our planet is something that NASA, its interagency partners, and the global community take very seriously," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate, in the statement. "While there are no known impact threats at this time, the 2013 Chelyabinsk super-fireball and the recent 'Halloween Asteroid' close approach remind us of why we need to remain vigilant and keep our eyes to the sky."

NASA has been working on planetary defense for some time – its Near-Earth Object Observations Program already works with astronomers and scientists around the world to look for asteroids that could harm Earth. The office will build on the agency’s existing efforts, working with the Federal Emergency Management Agency (FEMA) and other federal agencies and departments.

“In addition to detecting and tracking potentially hazardous objects, the office will issue notices of close passes and warnings of any detected potential impacts, based on credible science data,” explained NASA, in its statement. “The office also will continue to assist with coordination across the U.S. government, participating in the planning for response to an actual impact threat, working in conjunction with FEMA, the Department of Defense, other U.S. agencies and international counterparts.”

Given their cataclysmic potential it’s hardly surprising that asteroids remain a source of fascination for many people. Last August NASA’s Jet Propulsion Laboratory nixed rumors swirling around the Internet of an asteroid impact between sometime between Sept. 15 and 28, 2015.

NASA also has an ambitious plan to capture and redirect an asteroid.

http://www.foxnews.com/science/2016/01/11/nasa-will-tackle-asteroid...

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NASA launches new programme to defend Earth from asteroids

New York: NASA has started a new programme called the Planetary Defence Coordination Office (PDCO) which will coordinate the space agency's efforts to detect and track near-Earth objects (NEOs), a media report said.

Most asteroids and comets in our solar system are small and stay safely in orbit within the asteroid belt between Mars and Jupiter.

Others, however, are large enough to do damage and are in orbits that bring them close enough to our planet, Techcrunch.com reported.

In order to protect the Earth from these potential hazards, the PDCO has two main roles. First, it is responsible for finding and characterising these NEOs. Second, the PDCO is in charge of coordinating emergency efforts with other agencies and governments if a large NEO was predicted to impact the Earth.

In preparation of an impact of considerable size, NASA has long-term planetary defence goals that include the development of asteroid deflection technologies. So far, effective asteroid deflection strategies have not been decided upon, let alone developed.

NASA, however, said that it has an asteroid impact and deflection mission concept in the works with the European Space Agency. This mission, "if pursued" (funded), would "demonstrate an impact deflection method," the space agency said.

In the event of an unavoidable asteroid impact, PDCO would work in partnership with FEMA, the Department of Defence, and other US agencies and international counterparts to coordinate emergency efforts.

NEO encounters by themselves are not rare events, but usually they are small enough to burn up in our atmosphere. Between 1994 and 2013, NASA measured 556 bolide (bright explosion caused by an asteroid impact) events.

But the notable exception was the 2013 Chelyabinsk event (the large yellow dot in Russia on the map) which was the largest asteroid to hit the Earth during this time period.

The scary part was that NASA wasn't aware of the Chelyabinsk asteroid because it was relatively small (about 19 metres, in diametre) and in the weeks before it hit us it was too close to the Sun, making it difficult to detect.

http://www.ibnlive.com/news/tech/nasa-launches-new-programme-to-def...

Permalink Reply by Dr. Krishna Kumari Challa on August 20, 2014 at 11:03am

Near-Earth Asteroid Held Together by Unknown Force

The new discovery suggests better ways to deflect an incoming space rock

One of the most infamous near-Earth asteroids is held together by forces other than just gravity and friction. Researchers have found that asteroid (29075) 1950 DA is a loose blob of particles that clot together much as Moon dust collects on astronauts’ spacesuits.

Any mission to divert an asteroid on a collision course with Earth would need to take these newfound cohesive forces into account, suggest the findings, published in Nature on August 14. This means that gently nudging an asteroid onto a new trajectory is potentially a safer option than blasting it to smithereens.
http://www.scientificamerican.com/article/near-earth-asteroid-held-...

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Giant comets may pose danger to life on Earth

London :The discovery of hundreds of giant comets in the outer planetary system over the last two decades means that these objects pose a much greater hazard to life on Earth than asteroids, scientists say.

The giant comets, termed centaurs, move on unstable orbits crossing the paths of the massive outer planets Jupiter, Saturn, Uranus and Neptune.

The planetary gravitational fields can occasionally deflect these objects in towards Earth, according to a team of astronomers from Armagh Observatory and the University of Buckingham in UK.

Centaurs are typically 50 to 100 kilometres across, or larger, and a single such body contains more mass than the entire population of Earth-crossing asteroids found to date.

Calculations of the rate at which centaurs enter the inner solar system indicate that one will be deflected onto a path crossing Earth’s orbit about once every 40,000 to 100,000 years, researchers said.

Whilst in near-Earth space they are expected to disintegrate into dust and larger fragments, flooding the inner solar system with cometary debris and making impacts on our planet inevitable.

Known severe upsets of the terrestrial environment and interruptions in the progress of ancient civilisations, together with our growing knowledge of interplanetary matter in near-Earth space, indicate the arrival of a centaur around 30,000 years ago.

This giant comet would have strewn the inner planetary system with debris ranging in size from dust all the way up to lumps several kilometres across.

Specific episodes of environmental upheaval around 10,800 BC and 2,300 BC identified by geologists and palaeontologists are also consistent with this new understanding of cometary populations, researchers said.

Some of the greatest mass extinctions in the distant past, for example the death of the dinosaurs 65 million years ago, may similarly be associated with this giant comet hypothesis, they said.

“In the last three decades we have invested a lot of effort in tracking and analysing the risk of a collision between Earth and an asteroid,” said Professor Bill Napier from the University of Buckingham.

“Our work suggests we need to look beyond our immediate neighbourhood too, and look out beyond the orbit of Jupiter to find centaurs. If we are right, then these distant comets could be a serious hazard, and it’s time to understand them better,” said Napier.

The researchers have also uncovered evidence from disparate fields of science in support of their model.

For example, the ages of the sub-millimetre craters identified in lunar rocks returned in the Apollo programme are almost all younger than 30,000 years, indicating a vast enhancement in the amount of dust in the inner Solar system since then.

The research was published in the journal Astronomy and Geophysics.

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https://www.scientificamerican.com/article/how-to-stop-an-incoming-...

Permalink Reply by Dr. Krishna Kumari Challa on March 7, 2023 at 10:12am

New results from NASA's DART planetary defense mission confirm we could deflect deadly asteroids

What would we do if we spotted a hazardous asteroid on a collision course with Earth? Could we deflect it safely to prevent the impact?

Last year, NASA's Double Asteroid Redirection Test (DART) mission tried to find out whether a "kinetic impactor" could do the job: smashing a 600kg spacecraft the size of a fridge into an asteroid the size of an Aussie Rules football field.

Early results from this first real-world test of our potential planetary defense systems looked promising. However, it's only now that the first scientific results are being published: five papers in Nature have recreated the impact, and analyzed how it changed the asteroid's momentum and orbit, while two studies investigate the debris knocked off by the impact.

The conclusion: "kinetic impactor technology is a viable technique to potentially defend Earth if necessary".

Small asteroids could be dangerous, but hard to spot

Our solar system is full of debris, left over from the early days of planet formation. Today, some 31,360 asteroids are known to loiter around Earth's neighborhood.

Although we have tabs on most of the big, kilometer-sized ones that could wipe out humanity if they hit Earth, most of the smaller ones go undetected.

Just over ten years ago, an 18-meter asteroid exploded in our atmosphere over Chelyabinsk, Russia. The shockwave smashed thousands of windows, wreaking havoc and injuring some 1,500 people.

A 150-meter asteroid like Dimorphos wouldn't wipe out civilization, but it could cause mass casualties and regional devastation. However, these smaller space rocks are harder to find: we think we have only spotted around 40% of them so far.

The DART mission

Suppose we did spy an asteroid of this scale on a collision course with Earth. Could we nudge it in a different direction, steering it away from disaster?

Hitting an asteroid with enough force to change its orbit is theoretically possible, but can it actually be done? That's what the DART mission set out to determine.

Specifically, it tested the "kinetic impactor" technique, which is a fancy way of saying "hitting the asteroid with a fast-moving object".

The asteroid Dimorphos was a perfect target. It was in orbit around its larger cousin, Didymos, in a loop that took just under 12 hours to complete.

The impact from the DART spacecraft was designed to slightly change this orbit, slowing it down just a little so that the loop would shrink, shaving an estimated seven minutes off its round trip.

A self-steering spacecraft

For DART to show the kinetic impactor technique is a possible tool for planetary defense, it needed to demonstrate two things:

• that its navigation system could autonomously maneuver and target an asteroid during a high-speed encounter

• that such an impact could change the asteroid's orbit.

In the words of Cristina Thomas of Northern Arizona University and colleagues, who analyzed the changes to Dimorphos' orbit as a result of the impact, "DART has successfully done both".

The DART spacecraft steered itself into the path of Dimorphos with a new system called Small-body Maneuvering Autonomous Real Time Navigation (SMART Nav), which used the onboard camera to get into a position for maximum impact.

More advanced versions of this system could enable future missions to choose their own landing sites on distant asteroids where we can't image the rubble-pile terrain well from Earth. This would save the trouble of a scouting trip first!

Dimorphos itself was one such asteroid before DART. A team led by Terik Daly of Johns Hopkins University has used high-resolution images from the mission to make a detailed shape model. This gives a better estimate of its mass, improving our understanding of how these types of asteroids will react to impacts.

Asteroid statistics and the threats posed by asteroids of different sizes. Credit: NASA's DART press brief

Dangerous debris

The impact itself produced an incredible plume of material. Jian-Yang Li of the Planetary Science Institute and colleagues have described in detail how the ejected material was kicked up by the impact and streamed out into a 1,500km tail of debris that could be seen for almost a month.

Streams of material from comets are well known and documented. They are mainly dust and ice, and are seen as harmless meteor showers if they cross paths with Earth.

Asteroids are made of rockier, stronger stuff, so their streams could pose a greater hazard if we encounter them. Recording a real example of the creation and evolution of debris trails in the wake of an asteroid is very exciting. Identifying and monitoring such asteroid streams is a key objective of planetary defense efforts such as the Desert Fireball Network we operate from Curtin University.

A bigger than expected result

So how much did the impact change Dimorphous' orbit? By much more than the expected amount. Rather than changing by seven minutes, it had become 33 minutes shorter!

This larger-than-expected result shows the change in Dimorphos' orbit was not just from the impact of the DART spacecraft. The larger part of the change was due to a recoil effect from all the ejected material flying off into space, which Ariel Graykowski of the SETI Institute and colleagues estimated as between 0.3% and 0.5% of the asteroid's total mass.

A first success

The success of NASA's DART mission is the first demonstration of our ability to protect Earth from the threat of hazardous asteroids.

At this stage, we still need quite a bit of warning to use this kinetic impactor technique. The earlier we intervene in an asteroid's orbit, the smaller the change we need to make to push it away from hitting Earth. (To see how it all works, you can have a play with NASA's NEO Deflection app.)

But should we? This is a question that will need answering if we ever do have to redirect a hazardous asteroid. In changing the orbit, we'd have to be sure we weren't going to push it in a direction that would hit us in future too.

However, we are getting better at detecting asteroids before they reach us. We have seen two in the past few months alone: 2022WJ1, which impacted over Canada in November, and Sar2667, which came in over France in February.

We can expect to detect a lot more in future, with the opening of the Vera Rubin Observatory in Chile at the end of this year.

More information: R. Terik Daly et al, Successful Kinetic Impact into an Asteroid for Planetary Defense, Nature (2023). DOI: 10.1038/s41586-023-05810-5

Andrew F. Cheng et al, Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos, Nature (2023). DOI: 10.1038/s41586-023-05878-z

Cristina A. Thomas et al, Orbital Period Change of Dimorphos Due to the DART Kinetic Impact, Nature (2023). DOI: 10.1038/s41586-023-05805-2

Jian-Yang Li et al, Ejecta from the DART-produced active asteroid Dimorphos, Nature (2023). DOI: 10.1038/s41586-023-05811-4 Ariel

Graykowski et al, Light Curves and Colors of the Ejecta from Dimorphos after the DART Impact, Nature (2023). DOI: 10.1038/s41586-023-05852-9

by Eleanor K. Sansom

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