By Ashley Strickland Ko

Rising temperatures are causing ice to melt in regions that were once Earth’s coldest extremes — and revealing remnants of the ancient world.

Scientists have recovered well-preserved specimens of extinct creatures from Arctic permafrost, including a tissue fragment from a woolly rhino found within the stomach contents of a 14,000-year-old wolf pup.

Another research team was even able to revive a roundworm frozen 46,000 years ago, and it’s not the only thing scientists have awakened in a controlled environment after a long dormancy.

“Zombie viruses” and bacteria trapped and preserved for millennia in the now-thawing top layer of soil have sparked concern among some researchers. By reviving these ancient microbes in the lab, scientists are working to determine whether they could pose a threat to modern-day animals and humans.

A bacterial strain discovered in a 5,000-year-old layer of ice in Romania's Scarisoara cave (above) is resistant to 10 modern antibiotics.

Scarisoara cave in western Romania houses one of the world’s largest underground glaciers — and lurking within the ice is a 5,000-year-old strain of bacteria.

Scientists extracted samples from the 13,000-year-old monumental slab and revived the bacterial strain. The team found that it’s resistant to 10 modern antibiotics used to treat diseases such as urinary tract infections and tuberculosis.

“Ancient bacteria can resist modern antibiotics because antibiotic resistance is an ancient evolutionary characteristic that was shaped over millions of years by competition between microbes,” said Cristina Purcarea, a senior scientist in the department of microbiology at the Institute of Biology Bucharest of the Romanian Academy.

The cold-loving microbe, called Psychrobacter SC65A.3, does not endanger humans and could be used in the fight against modern superbugs.

Hydrogen, the lightest element in the universe, is a tiny, finicky molecule that packs a powerful punch.

Such a unique combination of properties makes it ideal for rocket fuel — but difficult to contain.

Engineers first began using hydrogen as rocket fuel in the mid-20th century in a trend that continues today. Nearly all launch vehicles relying on hydrogen — including the Apollo and Artemis moon rockets — have encountered leaks, but many trade-offs keep NASA using such fickle fuel.

The persistent leaks were kept under control for this week’s second attempt of the wet dress rehearsal, a crucial test of the Space Launch System rocket and Orion capsule. And NASA said it’s now aiming to launch Artemis II as soon as March 6, pending completion of some work at the launchpad and a flight readiness review.

Meanwhile, the troubled test flight of Boeing’s Starliner spacecraft — which turned into an unexpectedly monthslong stay in low-Earth orbit for NASA’s Butch Wilmore and Sunni Williams — was in the same league as US space shuttle disasters, according to a new report by the agency.

Watch a roughly 12-foot sleeper shark cruise past an underwater camera in the Southern Ocean, off the coast of the South Shetland Islands — a first-of-its-kind sighting. Many scientists didn’t think sharks could be found lurking in Antarctica’s deep, frigid waters, and some believe the creature’s presence may be a recent development.

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A recent wildlife survey in northern Saudi Arabia turned up an unexpected finding: the first known naturally mummified cheetahs, discovered in five caves.

Researchers dated the well-preserved remains from about 130 to 1,870 years ago, determining through DNA analysis that at least two subspecies of cheetah once roamed the Arabian Peninsula.

Today, only a small, critically endangered population of the Asiatic cheetah exists in Iran, and conservationists have deemed the cats extinct across the peninsula since the 1970s.

Understanding which cheetah lineages once successfully inhabited the peninsula could now be used to bring the rare cats back to Saudi Arabia.