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Fossil of Hemirhodon amplipyge trilobite, dating to the Cambrian Period. Photo: DeAgostini/Getty Images
On the banks of the Danshui River in China, scientists have unearthed a treasure-trove of pristine fossil remnants from one of the most important periods in the history of life on Earth.
The big picture: The Cambrian explosion, which occurred a little more than 500 million years ago and lasted for about 40 million years, is the period when nearly all the major groups of multicellular life forms currently on Earth first appeared. It was a period of frenzied evolutionary development and biodiversity buildup, mainly in the world's oceans.
Why it matters: Understanding the creatures that came into existence at that time will improve scientists' knowledge of where animals alive today fit into the planet's evolutionary history, and it could help researchers better understand some of the most complex organisms, such as humans.
What they found: The newly analyzed Qingjiang fossil site yielded 4,351 specimens, and it is expected to contain many more. So far, 53% of them are new to science, according to the study published Thursday in the journal Science.
Like other Cambrian fossil sites, the majority of fossils are of soft-bodied creatures, including jellyfish and sea anemones, both of which exist close to the base of the animal family tree.
The new life forms that first showed up during the Cambrian explosion include creatures that are related to modern animals, but would be utterly unrecognizable if you came across them today.
Study co-author Robert Gaines of Pomona College says the Qingjiang site shows that differences among fossil assemblages can be traced to environmental conditions that influence ecosystem structure.
One cool thing: Many of the Cambrian creatures were truly bizarre looking.
The bottom line: Gaines says a central lesson from the Cambrian explosion is that it takes a rare combination of ingredients to produce a tremendous diversity of life forms, and that once it exists, such biodiversity should be preserved.
The asteroid Bennu ejecting particles from its surface on Jan. 19, as seen from cameras aboard NASA’s OSIRIS-REx spacecraft. Photo: NASA
The near-Earth asteroid Bennu is an active asteroid that periodically ejects rocky material into space, according to early results from NASA's OSIRIS-REx Mission.
Why it matters: This is surprising, as the vast majority of known asteroids are inactive. In addition, NASA scientists hoping to land a spacecraft on Bennu to take samples back to Earth in 2023 have found the asteroid contains larger rocks than earlier thought, which could complicate the sampling mission.
What they found: The OSIRIS-REx mission began orbiting the asteroid on Dec. 31, seeking to learn more about its composition and movement. It's thought that some asteroids may contain material dating back to the beginning of our solar system, NASA says.
“The discovery of plumes is one of the biggest surprises of my scientific career,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “We don’t know the mechanism that is causing this right now," he said.
One cool thing: Scientists have identified magnetite on Bennu's surface, which is indicative of interactions between rock and liquid water, most likely on the parent body that the asteroid spun off from.
Meanwhile, some of the first discoveries of Japan's Hayabusa2 mission to the asteroid Ryugu were revealed in a series of studies published in Science on Tuesday.
12-week-old Grady, born from cryopreserved testicular tissue. Photo: Oregon Health and Science University
Scientists successfully froze immature testicular tissue and later transplanted it so it could mature and produce sperm that successfully led to a baby in primates — the first time a live birth resulted from a graft of this type of tissue, according to a study published in Science Thursday, Eileen Drage O'Reilly writes.
Why it matters: This research is a step toward the goal of young male cancer patients being able to reproduce later in life if they so choose.
As cancer treatments improve, more than 80% of U.S. kids who get cancer now survive, but 30% of those will have permanent infertility due to their treatments.
Background: While adult males can undergo successful cryopreservation of their sperm before their treatments start, prepubescent males' stem cells haven't yet gained the ability to turn into sperm.
What they did: Over a 2-year period, the research team removed and froze testicular tissue from 5 young rhesus macaques and implanted the tissue back into the monkeys once they reached puberty.
What they found: Both the fresh and frozen tissue had successfully and safely produced sperm.
"It was important to demonstrate that this would work with frozen and thawed tissues because young cancer patients may need to keep their tissues in cryostorage for years or even decades before they return to use those tissues to have a child," Orwig says.
Go deeper: Read the rest of Eileen's story.
Satellite view of flooding at Offutt Air Force Base in Nebraska, HQ of Strategic Command. Image: DigitalGlobe.
NOAA warns of "unprecedented flood season" across U.S.: The flooding in Nebraska is already a billion dollar disaster.
The "inland ocean" in the Indian Ocean: Water-borne diseases are a major threat given the lack of clean drinking water in the storm's wake.
World Health Organization calls for strong gene editing framework: Top experts warned it would be "irresponsible" to allow this in clinical practice.
Record flooding on Plains as seen through before and after photos: The extreme nature of the floods is best seen from high above.
Meet Aurora, soon to be the first "exascale" supercomputer in the U.S.: The performance will be one "exaFLOP," which is equal to a quintillion floating point computations per second.
People with untreated HIV transmitted 80% of new infections: The vast majority of new HIV infections in the U.S. in 2016 were transmitted from the less than 40% of people with HIV who were not receiving care, the CDC reports.
Tardigrades, also known as water bears or moss piglets, survive temporary freeze, extreme heat and stays in outer space. Photo: Waltraud Grubitzsch/picture alliance via Getty Images
Karen Uhlenbeck Is First Woman to Win Abel Prize for Mathematics (Kenneth Chang, NYT)
Scientists rise up against statistical significance (Valentin Amrhein, Sander Greenland, Blake McShane, Nature)
Biogen halts studies of closely watched Alzheimer’s drug, a blow to hopes for new treatment (Adam Feuerstein, StatNews)
The smallest and farthest worlds ever explored by NASA are really, really weird (Sarah Kaplan, Washington Post)
Science Says: Tiny ‘water bears’ can teach us about survival (Seth Borenstein, AP)
The near-Earth asteroid Bennu is spinning faster.
The reason is my favorite science acronym of the week: YORP, which stands for the Yarkovsky-O'Keefe-Radzievskii-Paddack effect, after its discoverers.
Details: As Bennu rotates through space, the sun heats the pile of boulders, sand and rocks unevenly, causing it to increase its rotation speed slightly. Because of this, the time it takes for the asteroid to complete a rotation around its axis of rotation is decreasing by about 1 second every 100 years, NASA said in a press release.
How it works: When an asteroid is warmed by sunlight, it gives off infrared energy.
According to Daniel Scheeres of the University of Colorado at Boulder, the asteroid Bennu may eventually spin itself apart, due to the tug of war between a gradually accelerating spin rate and its small gravitational field that is greatest around its equator.
“So far, that material has been trapped by gravity, but at some point, if the asteroid keeps spinning faster, then you fall off the cliff,” Sheeres said in a press release.
Thanks for reading, see you again next Thursday!