NASA on TuesdayCelebrated beyond expectations during a mission to deflect a distant asteroidIn a sci fi-fi-like examination of humanity’s ability stop a cosmic object threatening Earth from destroying life on Earth,
NASA chief Bill Nelson said that the fridge-sized Double Asteroid Redirection Test impactor (DART), deliberately struck into Dimorphos, causing it to orbit in a smaller, more efficient orbit around Didymos.
That changed its orbital period by four percent, or 32 minutes – from 11 hours 55 minutes to 11 hours 23 minutes, bettering an expectation of 10 minutes.
Nelson said to AFP, “At some time in the future if we find an asteroid threatening Earth and large enough for some damage, we will have this successful test.”
The asteroid pair orbits our Sun once every 2.1 year and is not a threat to our planet.
They are also ideal for studying “kinetic impact”, a method of planetary defense.
DART’s success as a proof-of-concept has made a reality what was once science fiction – notably films such as Armageddon, Deep ImpactAnd Don’t look up.
Never before photographed, Dimorphos measures 530 feet (160m) in circumference and is roughly the same size that a large Egyptian pyramid. It was visible as a speck around an hour before impact.
Its egg-shaped shape and boulder-dotted, craggy surface make it unique. Suddenly, it was clear.DART was racing towards it at approximately 14,500 miles (23.500 km) an hour.
Pseudo-comet
In the days that followed, astronomers rejoiced in stunning images of matter spreading out thousands of miles – pictures collected by Earth and space telescopes, as well as a tiny companion satellite that traveled to the zone with DART.
Dimorphos is now a man-made comet thanks to its temporary tail.
However, to quantify the effectiveness of the test, it was necessary to analyze light patterns taken from ground telescopes. This took several weeks.
Binary asteroid systems are visible as one dot at the ground. They were approximately 6.8million miles (11,000,000 km) away when they struck Earth.
As Dimorphos passes by Didymos, the dot’s brightness changes. Didymos is considerably larger at half a mile in diameter.
Four optical telescopes were involved in measuring the orbital period – all in Chile and South Africa – while two US-based radar telescopes helped confirm the finding, said NASA planetary scientist Nancy Chabot.
Researchers also found that the asteroid was less solid than a rock and more like an “rubbish pile”, composed of boulders bound by mutual gravitation.
A spaceship can only impart limited momentum to an asteroid that is larger and more solid. However, a spaceship can push significant mass at high velocity in the opposite direction of impact to give it an extra boost.
At a briefing, NASA scientist Tom Statler stated that “it looks like the recoil caused by the ejectablast off the surface was an important contributor to the overall push given asteroid.”
He said that the test will be used as an “anchor” to simulate and calculate future impacts.
Mass extinction
No known asteroid larger than 140 meters (460 feet) in size – big enough to devastate a city – has a significant chance to hit Earth for the next 100 years, according to NASA.
Wait long enough and it will happen.
For example, the geological record records that an asteroid measuring six miles in diameter struck Earth 66 millions years ago. It sank into the Earth’s long winter, causing mass extinction. dinosaursTogether with 75 percent for all species.
The agency will launch a telescope called Near-Earth Object Surveyor (NEO) in 2026 to better understand potentially dangerous 140-meter asteroids, and comets within 30 million miles.
Only half of the estimated 25,000 NEOs measuring 140 meters have been found so far.
The only way to defend the planet is by kinetic impact using a spaceship, but it’s the only option with the current technology.
If an object approaching is detected quickly, a spaceship can be sent to fly along its path using the ship’s gravity pull to divert it. This is called a gravity tractor.
Another option is to launch nuclear explosives to destroy or redirect an asteroid.
NASA believes that the best method to deploy such weapons is from a distance. This would allow the weapon to exert force without damaging the asteroid.
