A radar on Zhurong can penetrate the surface to a depth of 100 metres.Credit: Xinhua/Shutterstock
China’s Zhurong rover has peered deep under the surface of Mars, finding evidence of two major floods that probably shaped the region the robot has been exploring since it landed in May 2021.
An analysis published in Nature today1 is the first result from Zhurong’s radar imager, which can probe up to 100 metres below the surface. “It is a very interesting paper, and I was particularly impressed by how deep they can see with this radar,” says Svein-Erik Hamran, a planetary scientist at the University of Oslo, who analysed the only previous data from ground-penetrating radar used on the planet, collected by NASA’s Perseverance rover.
The history of Zhurong’s landing site — on Utopia Planitia, vast plains in Mars’s northern hemisphere — has puzzled scientists. Some have theorized that water or ice was once a feature of the landscape. Observations from space have identified sedimentary deposits that suggest the region was once an ancient ocean or submerged by huge floods, and geological features, such as pitted cones, resemble structures formed by water or ice. In May, researchers analysed infrared images of the landing site taken by China’s Mars orbiter, Tianwen-1, and found hydrated minerals that could have formed when groundwater rose through the rock or ice melted.
But the region could have also been covered in lava, concealing some of these hydrological processes in the subsurface. Eruptions from the volcano Elysium Mons to the east of the landing site, or other volcanic activity, could have covered the region in magma, as has been observed in other parts of the Utopia basin. By studying the radar data, researchers hope to understand what happened, and whether water or ice could still be lurking below the rocks. “We want to know what is going on beneath the surface,” says study co-author Liu Yang, a planetary scientist at the National Space Science Center in Beijing.
Below the surface
Zhurong is China’s first rover on the red planet, and it has been exploring the southern part of Utopia Planitia. The rover’s ground-penetrating radar transmits high-frequency radio waves that can penetrate the surface to a depth of between 3 and 10 metres, and low-frequency waves that can reach up to 100 metres underground but offer poorer resolution. The study authors analysed low-frequency data taken between 25 May and 6 September over more than 1,100 metres of terrain as Zhurong travelled south of its landing site. Radar signals reflect off materials under the surface, revealing the size of their grains and their ability to hold an electric charge. Stronger signals typically indicate larger objects.
The radar did not find any evidence of liquid water down to 80 metres, but it did detect two horizontal layers with interesting patterns. In a layer between 10 and 30 metres deep, the team reports, the reflection signals strengthened with increasing depth. The researchers say this is probably due to larger boulders resting at the base of the layer, and smaller rocks settling on top. An older, thicker layer between 30 and 80 metres down showed a similar pattern.
The older layer is probably the result of rapid flooding that carried sediments to the region more than three billion years ago, when there was a lot of water activity on Mars, says co-author Chen Ling, a seismologist at the Institute of Geology and Geophysics, Chinese Academy of Sciences, in Beijing.
The upper layer could have been created by another flood some 1.6 billion years ago, when there was lots of glacial activity. Chen says it is unlikely that the upper layer contains intact lava flows, because it has a smaller ability to hold an electric charge than would be expected for intact volcanic rocks. Furthermore, the researchers didn’t see any sudden changes in layering, which would be expected when lava flows meet sedimentary material.
Volcanic or sedimentary?
But, Chen says, it is possible that a thin coat of lava once covered the upper layer and it has gradually been broken down into smaller pieces. Radar data alone cannot definitively reveal whether material is sedimentary or volcanic, says Xu Yi, a planetary scientist at Macau University of Science and Technology.
Radar data are good at indicating the layering and geometry of subsurface material, but not so good at pinpointing its composition, including whether the material is ice or rock, says Hamran. Often, researchers rely on other clues, such as rocks peering out from the surface, to build a picture of past events, he says. The authors say they can’t rule out the possibility that the region contains buried saline ice.
More radar results are expected from the mission, including data taken during Zhurong’s continued traverse of Mars, results from the high-frequency radar measurements already made, and Tianwen-1’s orbital radar observations, which penetrate deep into the planet. They could help to clarify details of the terrain. “This is only the first step,” say Ling.
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.
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.
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.”
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.
