Madrid, Jun 29 (EFE) .- When we think of asteroids, large masses of stone that stalk the Earth come to our imagination, and this is partly so, but those rocks that roam space are also a source of scientific and technological wealth .
Raising public awareness of the opportunities and challenges that these objects represent is the task of Asteroid Day, which is celebrated every June 30, date in 1908 when a meteorite caused serious damage in Tunguska (Siberia), where it devastated 2,000 square meters of taiga.
Asteroids are the remains of the births of the planets of the Solar System and many are fragments of tiny protoplanets that never reached maturity, so their study is vital to understand the origin of our home in the universe.
“I see them as a source of scientific and technological wealth,” says astrophysicist Josep Maria Trigo, from the Institute of Space Sciences of the CSIC and the Institute of Space Studies of Catalonia.
More than 75% of asteroids are chondritic type. Amalgams of the primeval materials that condensed around the Sun 4.565 million years ago and, he explains, “contain the fossil remains of those early times, being rich in metals, rare earths, and some of them, even in primordial water.”
This year is special, because the return of the Japanese probe Hayabusa 2 is expected in December, which, after six years of mission, will return with fragments of Ryugu, a 900-meter diameter asteroid located 280 million kilometers from Earth.
When the pieces can be examined, it is hoped to obtain “a plethora of information”, as happened with the samples that Hayabusa brought from the asteroid Itokawa a decade ago, says Trigo, whose team was the only Spaniard who could examine them and aspires to do so. same with Ryugu’s.
But this is not the only asteroid that can be analyzed, because in three years the Osiris Rex mission from NASA should return with material from Bennu.
These two missions are an “exciting” moment, in the words of Javier Licandro, from the Canary Islands Institute of Astrophysics (IAC), who last week participated in one of the virtual talks organized by the European Space Agency (ESA) on the occasion of the Asteroid Day.
Hayabusa 2 and Osiris Rex are “complementary missions” that “are already giving surprising results,” said Lycandro, explaining that on the surface of the asteroids, it was expected that there would be a lot of dust, but in reality they are “basically a scree,” which complicated Find a place for the Japanese probe to land.
Meteorites, fragments of rocky bodies that reach Earth, may also contribute to the exploration of Mars, says Wheat.
In the analysis of the Martian meteorite ALH 84001, about 4.1 billion years old and discovered in Antarctica in 1984, the Wheat team found evidence of water.
This is just one example of the meteorites that enter our atmosphere each year, where they are normally destroyed, although some overcome that barrier and fall to Earth. The most famous is Chicxulub, which 66 million years ago hit the Gulf of Mexico and killed the dinosaurs.
And it is that “dinosaurs did not have a space agency” to monitor space, as recalled by an old and ironic ESA slogan printed on some of their shirts.
The risk of such a rock reaching Earth is not great, but there are many smaller and potentially dangerous ones, which is why there are identification and monitoring programs, and planetary defense projects are being launched.
Over the past two decades, “tremendous progress has been made” in identifying asteroids in the near-Earth region, says Wheat, but what’s important now is completing the search for those small objects.
75% of objects between a kilometer and 300 meters in diameter are already known, but between 300 and 100 meters we know only 15%, a percentage that drops to 0.5% for those between 100 and 30 meters, he adds the astronomer, who notes that the Tunguska meteorite is believed to have been no more than 50 meters.
But will it be possible one day to deflect an asteroid that threatens Earth? That is the objective of both planetary defense missions of ESA and NASA, which have their sights set on the asteroid Didymos, which is orbited by a smaller one called Dimorphos, whose size is similar to an Egyptian pyramid.
NASA’s DART probe will travel to this binary asteroid system in two years, making a hypervelocity kinetic impact against Dimorphos to try to vary its speed and deviate its course. “This seems the most consistent technique to apply with these small asteroids,” says Wheat.
Two years later, ESA’s Hera probe will visit “that fascinating binary system, to characterize both bodies and test the effects of the impact.”
Carmen Rodriguez
(c) EFE Agency
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