Oldest material on Earth found inside meteorite - CBC.ca | Canada News Media
Connect with us

Science

Oldest material on Earth found inside meteorite – CBC.ca

Published

 on


A scanning electron micrograph shows a silicon carbide grain, about 8 micrometres in its longest dimension, from a meteorite that crashed into Australia in 1969. The image was released in Chicago on Monday. (Janaina N. Avila via REUTERS)

A meteorite that crashed into rural southeastern Australia in a fireball in 1969 contained the oldest material ever found on Earth, stardust that predated the formation of our solar system by billions of years, scientists say.

The oldest of 40 tiny dust grains trapped inside the meteorite fragments retrieved around the town of Murchison in Victoria state dated from about seven billion years ago, about 2.5 billion years before the sun, Earth and rest of our solar system formed, the researchers said.

In fact, all of the dust specks analyzed in the research came from before the solar system’s formation — thus known as presolar grains — with 60 per cent of them between 4.6 and 4.9 billion years old, and the oldest 10 per cent dating to more than 5.6 billion years ago.

The stardust represented time capsules dating to before the solar system. The age distribution of the dust — many of the grains were concentrated at particular time intervals — provided clues about the rate of star formation in the Milky Way galaxy, the researchers said, hinting at bursts of stellar births rather than a constant rate.

“I find this extremely exciting,” said Philipp Heck, an associate curator at the Field Museum in Chicago who led the research published in the scientific journal Proceedings of the National Academy of Sciences.

“Despite having worked on the Murchison meteorite and presolar grains for almost 20 years, I still am fascinated that we can study the history of our galaxy with a rock,” Heck added.

The grains are small, measuring from 2 to 30 micrometres in size. A micrometre is a one-thousandth of a millimetre, or about 0.000039 of an inch.

Blown by stellar winds

Stardust forms in the material ejected from stars and carried by stellar winds, getting blown into interstellar space. During the solar system’s birth, this dust was incorporated into everything that formed, including the planets and the sun, but survived intact until now only in asteroids and comets.

The researchers detected the tiny grains inside the meteorite by crushing fragments of the rock and then segregating the component parts in a paste they described as smelling like rotten peanut butter.

Dust-rich outflows of evolved stars similar to the pictured Egg Nebula are plausible sources of the large presolar silicon carbide grains found in meteorites like Murchison. ( ESA/Hubble and NASA. Inset courtesy of Janaína N. Ávila)

Scientists have developed a method to determine stardust’s age. Dust grains floating through space get bombarded by high-energy particles called cosmic rays. These rays break down atoms in the grain into fragments, such as carbon into helium.

These fragments accumulate over time and their production rate is rather constant. The longer the exposure time to cosmic rays, the more fragments accumulate. The researchers counted these fragments in the laboratory, enabling them to calculate the stardust’s age.

Scientists previously had found a presolar grain in the Murchison meteorite that was about 5.5 billion years old, until now the oldest-known solid material on Earth. The oldest-known minerals that formed on Earth are found in rock from Australia’s Jack Hills that formed 4.4 billion years ago, 100 million years after the planet formed.

This is a large chunk of the Murchison meteorite from the Field Museum of Natural History meteorite collection in Chicago. The meteorite is a carbonaceous chondrite. (James St. John/Wikimedia Commons, licenced under CC BY 2.0)

Let’s block ads! (Why?)



Source link

Continue Reading

Science

The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

Published

 on

 

NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.

Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.

She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.

Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.

“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.

It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.

Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.

Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.

Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.

“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.

He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.

The Canadian Press. All rights reserved.

Source link

Continue Reading

News

The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

Published

 on

 

TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

Source link

Continue Reading

News

B.C. sets up a panel on bear deaths, will review conservation officer training

Published

 on

 

VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.

Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”

Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.

“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.

B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.

Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.

Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.

Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.

“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”

Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”

“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.

Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.

“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.

This report by The Canadian Press was first published Sept. 9, 2024.

The Canadian Press. All rights reserved.

Source link

Continue Reading

Trending

Exit mobile version