The article was originally published at The Conversation.
Svetla Ben-Itzhak is an assistant professor of space and international relations.
There is a dangerous environment on Earth. asteroids and comets crash into our planet as they zoom through space. Some of these are cause for concern because they are too small to pose a threat.
As a scholar who studies space and international security, it is my job to ask what the likelihood of an object crashing into the planet really is, and whether governments are spending enough money to prevent such an event.
One needs to know what near-Earth objects are out there to find the answers to these questions. 40% of the bigger ones have been tracked by NASA. Surprise asteroids have visited Earth in the past and will do so in the future. How prepared will humanity be when they show up?
A small asteroid is changed forever after a close flyby of Earth.
There are millions of objects on the sun. Near-Earth objects are asteroids and comets that will travel within 120 million miles of the sun.
Astronomers consider a near-Earth object to be a threat if it comes within 4.5 million miles of the planet and is at least 140 meters in diameter. If a body of this size crashes into Earth, it could cause a lot of damage. Larger objects could have global effects and even cause mass extinctions.
65 million years ago, an asteroid crashed into the Yucat Peninsula, causing a lot of damage. It wiped out most plant and animal species on Earth.
Smaller objects can cause damage. A body of water exploded in Siberia in 1908. More than 80 million trees are over two hundred square miles. An asteroid exploded in the atmosphere over Chelyabinsk, Russia, in 2013. It injured over 1,100 people and caused $33 million in damage.
2005 ED224 is the next large asteroid that could hit Earth. There will be a chance of an impact when the asteroid passes by on March 11, 2023.
The chances of a larger body impacting Earth are small, but the damage would be enormous.
The 1998 Spaceguard Survey was mandated by the U.S. Congress to find and track 90 percent of near-Earth objects within 10 years. NASA surpassed the goal in 2011.
The Congress passed a bill in 2005 that requires NASA to find at least 90% of all near-Earth objects by the end of 2020. The year was mostly due to a lack of financial resources and only 40% of the objects have been mapped.
Astronomers have found 28,266 asteroids, of which 10,033 are larger in diameter and at least 1 km across. 30 new objects are added each week.
A new mission is scheduled to launch in the year 2026 and is dedicated to searching for potentially dangerous asteroids.
asteroids have sneaked up on Earth before and we can only prevent a disaster if we know it is coming.
An asteroid the size of a football field passed less than half a mile from Earth in 2019. An asteroid the size of a jet came close to us in 2011. They were discovered a day before they passed Earth.
There is research suggesting that the Earth's rotation may cause a blind spot where some asteroids remain undetected. Some asteroids do not miss us, so this may be a problem. Astronomers spotted a small asteroid 19 hours before it crashed into Sudan. The recent discovery of an asteroid 1.2 miles in diameter suggests that there are still big objects on the horizon.
Early detection is important to protect the planet. Scientists recommended a minimum of five to 10 years preparation time to mount a successful defense against asteroids.
There are four ways to mitigate a disaster if an astronomer finds a dangerous object. The first involves first-aid and evacuate measures. A second approach would involve sending a craft to fly near the asteroid, and the gravity of the craft would slowly change the object's position. We can either crash something into the asteroid at high speeds or blow it up.
NASA launched the world's first full-scale planetary defense mission as a proof of concept: the Double Asteroid Redirection Test, or DART. There is no threat to Earth from the large asteroid Didymos and its small moon. NASA plans to crash a 1,340-pound probe into the Didymos moon at a speed of over 15,000 mph in September 2022.
Learning more about the composition of threatening asteroids is important, as it may affect how successful we are at defusing them. Bennu is 1,620 feet in diameter. There is a chance that it will collide with Earth on Sept. 24, 2182. NASA launched the OSIRIS-Rexprobe in 2016 to learn more about Bennu, an asteroid that could wipe out an entire continent. After arriving at Bennu, the spacecraft collected samples and will return to Earth in three years.
The planetary defense budget for NASA was $150 million in 2011. The total budget of NASA is just 0.7% of the US defense budget.
The budget supports a number of missions, including the DART at $324 million and Osiris Rex at $1 billion over several years.
Is this the right amount of money to invest in keeping an eye on the skies, given the fact that many potentially dangerous asteroids remain undetected? When considering the potential consequences, this is an important question to ask.
Buying homeowners insurance is similar to investing in planetary defense. People buy insurance even though they don't know if the house will be destroyed.
The destruction and loss of life would be extreme if a single object larger than 140 meters hit the planet. Most species on Earth could be wiped out by a bigger impact. The chance of a body hitting Earth in the next 100 years is not zero. Investing in protecting the planet from dangerous objects may give humanity some peace of mind and could prevent a catastrophe.
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