The best gift of this holiday season came in a small package, parachuted into the far Australian desert in our solar system on December 5, 2020.
Inside, astronomers were delighted to unravel the first significant samples of a rocky asteroid now 9 million kilometers away and returned to Earth in “perfect” shape.
The photos of the clean pebbles were finally released, and while the tiny, black grains on the inside look nothing but dirty coal, this galactic gift is not a rebuke. It is the culmination of a five-year journey that requires careful planning and execution.
The samples were initially collected by the Japanese mission Hayabusa2, which was sent in a circle and tested the diamond-shaped asteroid called Ryugu, following the success of its first mission.
Samples from the Ryugu asteroid in the re-entry capsule weigh about 5.4 g! This far exceeds the target yield of 0.1 g (the amount required for the initial scientific analysis) established during the design of Hayabusa2.
(Article in Japanese: https://t.co/IZFGinhuFc)– HAYABUSA2 @ JAXA (@ haya2e_jaxa) December 18, 2020
The original Hayabusa spacecraft returned from the asteroid Itokawa in 2010 with the first direct sample of an object close to Earth. In total, the surface material weighed less than a milligram, and yet this was still enough to provide crucial information about the asteroid’s age and geological history.
The new Ryugu samples – collected last year – date even further and contain more material than astronomers have dared to expect, weighing about 5.4 grams.
The name Ryugu refers to an underwater “dragon palace” in Japanese folklore, in which a fisherman is presented with a mysterious box with which to return home – rather like Hayabusa’s sealed capsules.
The treasure in this case is believed to be over 4.5 billion years old – a relic of our early solar system, which contains potentially ancient materials that once formed the Sun and its orbiting planets.
By carefully opening the sealed chambers, astronomers found many particles larger than a millimeter. Those in Room C were slightly larger than the rest and were collected from the second touchdown of the mission.
Sample capture chamber A, captured with an optical microscope. (JAXA)
Because this landing took place just north of a deliberately created crater earlier in the mission, the researchers expected the sample to contain pieces of underground material. This would be the realization, because all the other asteroid samples collected in space come only from the surface.
Prior to these direct samples, most of our knowledge about asteroids came from meteorites, which are asteroids or comets that wake up to hit the Earth’s surface.
Unfortunately, without the protection of a man-made capsule, much of that material is destroyed or contaminated by the atmosphere of our planet at the entrance, not to mention all the weather conditions that occur once these rocks come to rest on earth.
Ryugu is a type C asteroid, which means that its rock is very porous and contains a lot of carbon and water. Astronomers suspect that this special pile of dark debris formed billions of years ago, when it broke another large body of stone somewhere in the asteroid belt between Mars and Jupiter.
Because Ryugu’s surface looks unusually dry and red, some experts believe he once flew closer to the Sun.
However, not all the material collected in these containers is so important. One of the capsules contains an obvious anachronism (pictured below).
Sample capture chamber C, captured with an optical microscope. (Jaza)
“The artificial material seems to be present in room C,” reads a press release from the Hayabusa project2.
“The origin is being investigated, but a likely source is the scraped aluminum from the spacecraft’s test horn, as the projectile was fired to shake the material during landing.”
Later, a update on Twitter they said the object was still unconfirmed, but that it could have been separated from the sampling horn used during the collection.
The cleaning work for the Ryugu sample is constantly progressing. On December 21, the B&C sampling chambers were opened and then the contents of the A&C chambers were moved to the collection containers in the photo. The largest particles in chamber C are about 1 cm! pic.twitter.com/yWO15cKhG9
– HAYABUSA2 @ JAXA (@ haya2e_jaxa) December 24, 2020
Scientists are already beginning to analyze these new samples, including some gases trapped inside the capsules, which are believed to have been collected on the surface of Ryugu.
If the researchers are right, it will be the world’s first gas sample returned from deep space.
Even the present really.