内容摘要：President Joe Biden pauses before he addresses the nation from the Oval Office of the White House in Washington, Wednesday, July 24, 2024, about his decision to drop his Democratic presidential reelection bid. (AP Photo/Evan Vucci, Pool)

President Joe Biden pauses before he addresses the nation from the Oval Office of the White House in Washington, Wednesday, July 24, 2024, about his decision to drop his Democratic presidential reelection bid. (AP Photo/Evan Vucci, Pool)

Natural Resources Conservation Service, Conway, Ark. (5,171 square feet)Geological Survey, Corvallis, Ore. (6,849 square feet)

Railroad Retirement Board, Covina, Calif. (2,270 square feet)National Park Service, Crane Lake, Minn. (2,512 square feet)United States Fish and Wildlife Service, Daphne, Ala. (7,087 square feet)

Natural Resources Conservation Service, Dayton, Wash. (4,320 square feet)Office of the Inspector General, Diamond Bar, Calif. (3,058 square feet)

United States Fish and Wildlife Service, Doral, Fla. (7,747 square feet)

Geological Survey, Dover, Del. (5,724 square feet)The Chinese Academy of Sciences’ Sen Hu said he and his team received 5 grams of soil samples, then selected 578 particles for detailed analysis using electron microscopes.

They estimated the water abundance at less than 1.5 micrograms per gram, on the dry end of what’s been found in samples gathered over past decades from the moon’s near side. Measurements on samples from the near side have ranged between 1 microgram and 200 micrograms per gram.Given the limited sampling, it’s uncertain how widespread this dry condition might be, the scientists noted in their study published in the journal Nature.

“More far side samples are required for testing and further unraveling” how much water there is, Hu said in an email.It’s possible the impact that created this basin may have blasted water elements to the near side, leaving the far side depleted. Another possibility is that the vertical distribution of water could be different between the two hemispheres.