Harvard Scientists Say Earth Was Struck by an Interstellar Object 5 Years Ago

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It was unprecedented. In 2017, astronomers discovered the first known interstellar object in our Solar System: ‘Oumuamua, a mysterious cigar-shaped enigma, identified as our first visitor from outer, outer space.

But just because ‘Oumuamua was the first detected interstellar object, doesn’t mean it was the first ever. Just five years ago, in fact, Earth’s atmosphere was struck by something that may have originated far outside our own Solar System – and we never even realised it.

In a new paper, a pair of Harvard researchers propose that a meteor that collided with Earth’s atmosphere in January 2014 was actually another interstellar traveller with distant, mysterious origins.

But unlike the hurtling ‘Oumuamua – which is on a 20,000-year trajectory that will see it eventually exit our Solar System – this meteor’s long journey was fated to be a one-way ticket, ending with a fiery finale five years ago, as the object burnt up in the skies above Papua New Guinea.

While ‘Oumuamua is a large object, and was detected very far from Earth, the team behind the meteor hypothesis says much smaller interstellar immigrants could be far more commonplace, and potentially exist a lot closer to home.

“Instead of looking far out into space, and given the fact that there should be a higher abundance of interstellar objects smaller than ‘Oumuamua, we thought, ‘Why not look locally and find these smaller interstellar objects as they collide with the Earth’s atmosphere?'” first author, astronomer Amir Siraj told Newsweek.

Working with Harvard astrophysicist Avi Loeb, Siraj pored through a catalogue of meteor impacts kept by NASA’s Centre for NEO Studies (CNEOS).

Hidden in the CNEOS data, there lurked a remarkable outlier: a 2014 fireball that rushed Earthwards at a velocity of around 60 kilometres per second (37 mps) as it passed the Sun.

We can be grateful that this object was quite small – less than a metre across in total – because if it were significantly larger, it could have made for a disastrous impact with Earth’s surface, rather than the harmless atmospheric fizzle that eventuated.

But that happy anti-climax isn’t the primary takeaway of the meteor’s blistering speed.

When Siraj and Loeb calculated the meteor’s orbital trajectory based on its velocity, their numbers suggested the object wasn’t orbitally bound to the Sun: it was travelling so fast before its fiery end, it slipped straight through the Sun’s gravitational pull.

For that to be possible, the researchers suggest, the meteor had to originate from somewhere else, far beyond our Solar System.

Per their calculations, the meteor’s speed “implies a possible origin from the deep interior of a planetary system or a star in the thick disk of the Milky Way galaxy”.

It’s a wild idea, but while the findings remain purely hypothetical for now, Siraj and Loeb’s paper – which has not yet been peer-reviewed – has been welcomed by some in the astronomy community.

“I think it is reasonable to conclude that this very high speed impactor came from the population of interstellar objects,” theoretical astrophysicist Kat Volk from the University of Arizona, who wasn’t involved with the study, told National Geographic.

“I expect interstellar objects to be common enough – both from theoretical considerations and from the implications of ‘Oumuamua – that I think an interstellar origin is the simplest explanation for this bolide.”

But while ‘Oumuamua’s discovery has definitely shifted the landscape, helping to make real the previously theoretical underpinnings of interstellar migrations, not everybody is yet convinced that this 2014 bolide held such a fantastic passport.

“The result is interesting, but rests upon measurements for a single event,” astronomer Eric Mamajek from NASA’s Jet Propulsion Laboratory told Science News.

“Was the event a statistical fluke or an actual interstellar meteor?”

The jury is still out on that one, but the hypothetical possibilities in this area of science are as beguiling as an invitation to trek beyond the stars.

Per Siraj and Loeb’s calculations, these interstellar bolide events would have already occurred countless times in Earth’s history, and by looking out for future visits, we could learn much about these distant travellers’ backgrounds.

“Future meteor surveys could flag incoming objects with excess heliocentric velocities for follow-up pre-impact observations,” the researchers write.

“Spectroscopy of gaseous debris from these objects as they burn up in the Earth’s atmosphere would reveal their composition… Potentially, interstellar meteors could deliver life from another planetary system and mediate panspermia.”

Any way you look at it, amazing things are coming our way.

The findings are available on the pre-print website arXiv, and have been submitted to the Astrophysical Journal Letters.

Astronomers Finally Spot Universe’s First Molecule in Distant Nebula

It was the first molecule to form after the Big Bang.

A flying observatory has pinpointed the first type of molecule that formed in the universe after the Big Bang.

Helium hydride — a combination of helium and hydrogen — was detected roughly 3,000 light-years from Earth by NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA). The molecule was found in a planetary nebula, NGC 7027, which is the dusty remnant of a sun-like star. 

For hundreds of thousands of years after the Big Bang, the universe was too hot and too full of radiation for atoms to bond together. At that time, only a few types of atoms existed, including hydrogen, helium and lithium. However, the new study shows that 100,000 years after the Big Bang, the universe cooled enough for helium and hydrogen to combine, forming the molecule known as helium hydride. 

While helium hydride has been produced and tested in a laboratory setting, this discovery marks the first time that the molecule has been detected in space — which sheds light on the chemistry of the early universe, according to a statement from NASA. 

“This molecule was lurking out there, but we needed the right instruments making observations in the right position — and SOFIA was able to do that perfectly,” Harold Yorke, director of the SOFIA Science Center in California’s Silicon Valley, said in the statement

Once the universe cooled down, hydrogen atoms started to interact with helium hydride, creating molecular hydrogen, which set the stage for star formation. From that point on, stars created the other elements of the cosmos, according to the statement.

“The lack of evidence of the very existence of helium hydride in interstellar space was a dilemma for astronomy for decades,” Rolf Guesten, lead author of the study from the Max Planck Institute for Radio Astronomy in Bonn, Germany, said in the statement. 

NGC 7027 has been a location of interest for helium hydride since the late 1970s. Ultraviolet radiation and heat from the aging star led scientists to believe that its environment would be suitable for helium hydride to form. However, astronomers were unable to confirm this theory until now. 

The SOFIA instrument is a telescope that is flown on a Boeing 747-SP airplane at up to 45,000 feet, where its observations are not impacted by interference from Earth’s atmosphere. SOFIA returns to Earth after every flight, allowing scientists to regularly update the instrument with the latest technology. One of the most recent upgrades included adding a specific channel to detect signatures of helium hydride, which previous telescopes did not have.

“This flexibility allows us to improve observations and respond to the most pressing questions that scientists want answered,” Naseem Rangwala, SOFIA deputy project scientist, said in the statement.

Their findings were published April 17 in the journal Nature.

Manual Command Likely Caused Israeli Moon Lander’s Crash

Final results of the crash investigation are expected in the coming weeks.

Israel's Beresheet spacecraft snapped this selfie shortly before crash-landing on the moon on April 11, 2019.

Israel’s Beresheet spacecraft snapped this selfie shortly before crash-landing on the moon on April 11, 2019.(Image: © SpaceIL/IAI)

A preliminary investigation into what caused Israel’s Beresheet spacecraft to crash-land on the moon April 11 puts the apparent blame on a  “manual command” that was entered into the spacecraft’s computer.

“This led to a chain reaction in the spacecraft, during which the main engine switched off, which prevented it from activating further,” according to a statement released today (April 17) by Beresheet’s handlers, the nonprofit group SpaceIL and the company Israel Aerospace Industries (IAI).

Teams continue to investigate further, in order to understand the full picture of what occurred during the mission, the statement says. “In the coming weeks, final results of the investigation will be released.”

Related: Israel’s 1st Moon Lander Beresheet in Pictures

LRO lookout

Meanwhile, researchers are on the lookout for a NASA piggyback experiment that may have survived Beresheet’s destructive April 11 crash landing.

NASA’s Lunar Reconnaissance Orbiter (LRO) will target the crash site repeatedly, eyeing the area with its high-powered cameras. In addition, LRO will use its onboard Lunar Orbiter Laser Altimeter (LOLA) in an attempt to detect a NASA-provided laser retro-reflector array in the Beresheet wreckage zone.

Called the NASA Goddard Space Flight Center/MIT Laser Retroreflector Array(LRA) for Lunar Landers, the ball-shaped device was located on the top side of Beresheet.

The size of a computer mouse, LRA is composed of eight mirrors made of quartz cube corners that are set into a dome-shaped aluminum frame. That array is lightweight, radiation-hardened and long-lived.

From the high-flying LRO, laser beams generated by LOLA would strike the device and then bounce back to the orbiter. For each laser beam, LOLA measures its time of flight, or range.SpaceIL’s Beresheet Took Selfie Minutes Before Crashing Into MoonVolume 0% 

Overhead passes

While there will be many attempts to target the wreckage, LRO is directly over the site only twice per month, and one of those passes occurs in darkness (which is not an issue for the laser), explained the Massachusetts Institute of Technology’s David Smith, the principal investigator for LOLA and an emeritus researcher at NASA Goddard in Greenbelt, Maryland.

“But the site can be viewed on several passes around the ‘overhead’ pass by looking off to the side or forward or backward. This requires the spacecraft to slew or roll to see the target,” Smith said. 

“That’s a decision that LRO makes to ensure there are no issues with regard to constraints on pointing close to the sun or star cameras being able to see the stars (and not the lunar surface),” he added., So, the process requires requests for slew and role magnitudes and directions to the LRO project for a specific observation time.‘Return to the Moon: Seconds to Arrival’ – Science Channel ClipVolume 0% 

Pointing requests

This is normal procedure, Smith said, but typically researchers need to submit pointing requests about a week in advance. That allows the LRO project to check on pointing abilities (there are limits) of LRO and on thermal effects and spacecraft solar array pointing for charging the batteries.

“It may take 10 to 15 minutes for the spacecraft to turn to the desired direction and another 15 minutes to return to its normal nadir mode for just a few seconds of observations,” Smith told Inside Outer Space.

“I am sure the project will start to attempt observations as soon as possible,” Smith said. LRO’s camera system and the laser are co-boresighted, “so when the camera slews to take an image, the laser altimeter automatically goes with it and will attempt to make a range observation at the same time.”

At a speed of over 3,300 mph (5,310 km/h), the whole LRO observation period is over in a few seconds, Smith said.

Leonard David wrote the forthcoming book “Moon Rush: The New Space Race,” to be published by National Geographic in May 2019. A longtime writer for Space.com, David has been reporting on the space industry for more than five decades. Follow us on Twitter @Spacedotcom or Facebook