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By Jason Davis
Maybe "Oumuamua was not the first visitor to another star system.
As the mysterious, stadium-sized object swept our Sun before it vanished in 2017, scientists thought they were watching a rare event. However, a recent newspaper suggests that an Oumuamua-like object in pint form was found in 2014, briefly flaming as a meteor in the sky over Papua New Guinea.
The newspaper's authors, Harvard astronomer Avi Loeb and Harvard student Amir Siraj, picked up data from a worldwide network of US government sensors scanning the sky for rockets and instead searched for meteors that were fast enough outside the solar system. They found a knife-sized object rammed into the earth at a speed of 37 miles per second, and tracing its path concluded it was coming from interstellar space.
It is assumed that the object has dissolved before it has reached the bottom, but its existence opens up the possibility that firsthand interstellar objects could be investigated. Loeb said the government system could be modified to alert scientists when a fast-moving meteor is discovered so they can search for fragments that have survived all the way to the ground.
"It's a new way to look for interstellar objects," said Loeb, who raised his eyebrows in 2018 when he said that Oumuamua could be an alien spaceship. "It saves you travel, you do not have to go into another planetary system, you get material objects that you may be able to examine."
If confirmed, the discovery of the meteor means that our solar system was visited by two interstellar objects in just three years. Loeb said this means that there should be at least a million more objects that we can not see whizzing through the inner solar system at all times, and that an interstellar meteor hits Earth every 10 years.
Sow life on earth
Astronomers have long hypothesized that asteroids or comets could have transported the organic molecules that became the building blocks of life to the ancient earth. However, there is no rule that says they had to come from our own solar system.
Asteroids are rockier, while comets are icy. "Oumuamua looked like an asteroid, but moved like a comet and spit out gas. Once one of these objects reaches our atmosphere, it becomes a meteor, and every piece that survives all the way to the ground becomes a meteorite.
The potential discovery of an interstellar meteor has a fascinating possibility: Scientists could potentially investigate interstellar meteorites to see if they could transport life between star systems.
"We suspected that panspermia, the seeding of life between planets and planetary systems, can help spread life in our galaxy," said Franck Marchis, a senior planetary astronomer at the SETI Institute in Mountain View, California. "It's going to be great to get a fragment of it [an interstellar meteor] Really understand the conditions of the long journey between the stars. "
He added that such a journey could take millions of years and organic molecules need to be well protected to survive.
Just a simple old meteor?
Not everyone is convinced that the meteor identified by Loeb and Siraj originated outside our solar system. The government will not say how accurate the sensors are. Therefore, it is impossible to know exactly how the actual speed and direction of the object match the reported object.
"I do not think we can rule the border [inside our solar system] Trajectories based on available evidence " Californian astronomer Quanzhi Ye said on Twitter, Peter Brown, a meteor astronomer at the University of Western Ontario, called the uncertainties a "huge red flag," adding, "It's very difficult to measure orbits and velocities with sufficient accuracy to be able to say definitively," This particular is interstellar. & # 39; "
Loeb and Siraj address the uncertainties in their article and refer to two earlier studies comparing the state sensor data with the results of known calibrated sensors. One study found that meteoric velocities could drop by as much as 28 percent, but Loeb said a 45 percent speed error would be required for the Papua New Guinea meteor to come out of the solar system.
Finally, scientists may be able to use telescopes equipped with special equipment to burn interstellar meteorites in the atmosphere and decode their compositions from the traces of the burning gas they leave behind. This could mean more opportunities for scientists studying asteroids and comets to learn more about the formation of other star systems.
"We want to understand how the building blocks of the planets formed around our sun," said Michele Bannister, a postdoctoral fellow at Queen's University Belfast in Northern Ireland. "Is this the same for other stars as well? That's the basic process we're trying to investigate here: how did the building blocks of the planets grow and grow?"
Bannister said she was still unconvinced that the Papua New Guinea meteor came from outside the solar system. "But they ask the right scientific question," she said about Loeb and Siraj.
In an unpublished paper, Loeb raises the hypothesis that interstellar meteors could be a way for aliens to communicate with Earth dwellers, though he acknowledges that the idea is far-fetched: "Some of them may even represent technical equipment of alien civilizations Randomness passed by, just like a plastic bottle that was swept ashore against the backdrop of natural shells. "
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