This article was originally published on The Conversation. (opens on new page) The book contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.
Svetla Ben-Itzhak (opens on new page)Faculty of Space and Earth Relations, West Space Seminar, Air War College, Air University
The world is in danger. Cosmic bodies, such as asteroids and comets, are constantly expanding in the sky and frequently crashing into our planet. Most of these little things can be intimidating, but some can be a source of anxiety.
As an expert on climate and global security, my job is to ask how something can fall to Earth – and whether governments will spend the money to do so. prevent that event.
To find the answers to these questions, you need to know things close to Earth. Today, NASA has observed about 40% of the major objects (opens on new page). Amazing asteroids have visited Earth in the past and it is doubtful that it will happen in the future. When they are seen, how ready is the person?
Select: The orbit of a small asteroid constantly changes after Earth orbits
The threat from asteroids and comets
Millions of different things make up the sun. Those close to Earth include asteroids and comets whose orbits take them within 120 million miles. (opens on new page) (193 million kilometers) of the sun.
Astronomers think something close to Earth would be a threat if it came within 4.6 million miles. (opens on new page) (7.4 million km) of Earth and is 460 feet (140 meters) in diameter. If a celestial body of this size falls to Earth, it can destroy the entire city and end the great disaster of the Earth. Larger objects – 0.6 miles (1 km) or more – can have earth effects until they are destroyed.
The most famous impact and destruction occurred 65 million years ago when a 6-mile (10-km) in diameter asteroid crashed into what is now the Yucatán Peninsula. It wiped out most of the plants and animals on Earth, including dinosaurs.
But small things can hurt a lot. In 1908, a 164 -foot (50 -meter) celestial body exploded over the Tunguska River in Siberia. It has planted more than 80 million trees over 830 square miles (2,100 square km). In 2013, only 65 feet (20 meters) on the side exploded in the sky 20 miles (32 km) over Chelyabinsk, Russia. It dropped as many as 30 Hiroshima bombs worth of energy, injured more than 1,100 people and injured $ 33 million in the disaster.
The largest asteroid that can hit Earth is the 2005 asteroid ED224. When the 164-foot (50-meter) asteroid passes on March 11, 2023, there will be about 1 to 500,000 potential impacts. (opens on new page).
Look at the sky
While there is little time for a large cosmic body to attack Earth, there is a lot of damage.
The U.S. Congress recognized this threat, and in the 1998 Spaceguard Survey (opens on new page), NASA has worked to find and track 90% of the objects close to Earth 0.6 miles (1 km) in between over a 10 -year period. NASA is better than the target by 90%. (opens on new page) in 2011.
In 2005, the Legislature passed a bill (opens on new page) requiring NASA to increase its search and follow about 90% of the objects close to Earth 460 feet (140 meters) or more by the end of 2020. That year has come and gone and , Mainly due to lack of financial resources. (opens on new page)Only 40% of them are written (opens on new page).
From Feb. 14, 2022, found 28,266 astronomers (opens on new page) The closest asteroids to Earth, which are 10,033 are 460 feet (140 meters) in diameter and 888 are about 0.6 miles (1 km) in diameter. About 30 new ones are added each week.
A new mission, supported by Congress in 2018, is set to launch in 2026 an infrared, space -based telescope – NEO Surveyor – dedicated to tracking dangerous asteroids.
Cosmic wonders
We can only avoid a catastrophe if we know it is coming, and that asteroids have already flown over Earth.
An asteroid the size of a football field – dubbed the “City -killer” – will pass less than 45,000 miles from Earth in 2019. An asteroid is close to the size of a 747 aircraft per year. 2021 is the same as the 0.6-mile (1-km) wide asteroid in 2012. Each of these objects was seen about a day before they left Earth.
Research reveals one reason why the Earth is turning blind (opens on new page) where no other asteroids have been seen. This may be a problem, because some amazing asteroids are not missing from us. In 2008, astronomers saw a small asteroid 19 hours before it crashed in the Sudanese countryside. And the discovery of a 1.2 mile (2 km) in diameter asteroid shows that there are still important things to hide.
What can be done?
To protect the planet from cosmic disasters, prior knowledge is key. At the 2021 Planetary Defense Conference, scientists said it would take at least five to 10 years of preparation to put in place a defensive shield against dangerous asteroids.
If the astrologers see something terrible, there are four ways (opens on new page) to reduce damage. The first is about first aid measures and evacuation. The second method involves sending an aircraft to fly close to a small or medium -sized asteroid; The gravity of the ship slowly changes the orbit of the object. To change the course of a larger asteroid, we can either push something into it at high speed or destroy a nearby nuclear warhead.
This may sound like far -fetched ideas, but in November 2021, NASA launched a full -fledged planetary defense mission around the world as a testament to the idea: the Double Asteroid Redirection Test, or DART. The giant asteroid Didymos and its small moon do not threaten Earth. In September 2022, NASA plans to change the orbit of the asteroid by launching a 1,340-pound (610 kg) probe into the moon Didymos at a speed of 14,000 mph (22,500 kph).
It is also important to learn about how threatening asteroids work, because their composition is related to the success of our conversion to them. The Bennu asteroid is 1,620 feet (490 meters) in diameter. His orbit will take him very close to Earth in Sept. 24, 2182, and is 1 in 2,700 (opens on new page) necessity of meeting. An asteroid of this size could sweep the entire Earth, so to learn more about Bennu, NASA began the OSIRIS-Rex search in 2016. The plane arrived in Bennu, took pictures, collect samples and must return to Earth in 2023.
Turns out the earth shield
By 2021, NASA’s earth defense fund will be $ 158 million. This is only 0.7% of NASA’s total funding and only 0.02% of the $ 700 billion 2021 U.S. defense budget.
This money supports several missions, with NEO Surveyor at $ 83 million, DART at $ 324 million and Osiris Rex at about $ 1 billion over the years.
This is a reasonable amount to spend looking at the sky, as there are about 60% of asteroids that cannot be seen. (opens on new page)? This is an important question when one considers the consequences to come.
Investing in insurance is like buying homeowners insurance. The least likely is to have an event that destroys your home, but people buy insurance.
If an object hits more than 460 feet (140 meters) on the ground, there is more damage and loss of life. The catastrophe could actually wipe out most species on Earth. Even if the body of such a body is not expected to touch Earth in the next 100 years, it is not without time. In this low -cost and high -impact scenario, investing in protecting the earth from cosmic disasters gives man peace of mind and can prevent disaster.
This article is republished The Conversation (opens on new page) under the Creative Commons license. Read to Original article (opens on new page).
Follow Expert Voices issues and debates – and be part of the discussion – on Facebook and Twitter. The opinions expressed are those of the author and should not necessarily reflect the opinion of the publisher.
