Theresa Machemer

Theresa Machemer is a freelance writer based in Washington DC. Her work has also appeared in National Geographic and SciShow. Website: tkmach.com

A nurse administers the Pfizer-BioNTech COVID-19 vaccine to a patient in London on December 8. Some experts say the fastest way to test second-generation COVID-19 vaccines is through human challenge trials.

A Brief History of Human Challenge Trials

For more than two centuries, scientists have been intentionally infecting patients with dangerous diseases in order to learn more

PEZ has designed about 1,400 different character heads and innumerable variations.

How PEZ Evolved From an Anti-Smoking Tool to a Beloved Collector's Item

Early in its history, the candy company made a strategic move to find its most successful market

The vaccination effort underway is the biggest in United States history.

Distribution Begins for First Covid-19 Vaccine Authorized in the United States

Pfizer-BioNTech’s vaccine received emergency use authorization from the FDA last week

Tasmanian devils nip at each other's faces while eating carcasses and during mating season, providing opportunities for infectious face cancer to spread.

Study Offers Hope for Tasmanian Devils, Once Thought Doomed by Infectious Cancer

In the late 1990s, one affected devil infected an average of 3.5 others, but now each only infects about one

About two dozen dogs were removed from the study because they were too excited and couldn't provide clear data.

Dogs Can't Tell the Difference Between Similar-Sounding Words

Sit, sat or set? It's all the same to Fido as long as you give him a treat

The world's highest-altitude peak is called Sagarmatha in Nepal and Chomolungma in Tibet.

Is Mount Everest Really Two Feet Taller?

The new height measurement comes from an updated survey and decades of slow tectonic movement, not a sudden growth spurt

Researchers recorded 38 instances of pandas covering themselves in horse manure between June 2016 and June 2017.

In Winter, Pandas Love to Roll in Horse Poop

To deal with crappy weather, the black-and-white bears may be slathering themselves in feces to stay warm

The new A.I. systems are more complex than this bot photographed in 2005.

Human Interruption Slows Down Military Robots in Simulations

A.I. can make decisions faster than humans, raising a myriad of ethical questions when applied to weapons systems

Surveyor 2 launched on a Centaur/Atlas rocket in September of 1966. The upper stage, called Centaur, was lost in space until it returned to Earth's orbit this November.

Astronomers Confirm Earth's Newest Mini-Moon Is Actually a Long-Lost Rocket

The piece of space debris, called 2020 SO, is the upper stage rocket booster from a failed 1966 mission to the moon

The researchers worked with otters at Newquay Zoo, Tamar Otter and Wildlife Centre and New Forest Wildlife Park.

Otters Solve Puzzles Faster After Seeing a Friend Do It First

Conservation scientists could use the information to teach previously captive animals how to live in the wild

AlphaFold's protein structure in blue is shown overlaid with the lab results in green for two kinds of proteins.

Breakthrough A.I. Makes Huge Leap Toward Solving 50-Year-Old Problem in Biology

Proteins are vital biological molecules, and it can require years of lab-based experiments to tease out the 3-D shape of just one

A keyhole wasp can block up an airplane's external sensor in as little as 30 minutes.

In Australia, Just One Wasp Can Ground an Airplane With a Strategically Placed Nest

Invasive keyhole wasps were building nests in the equipment pilots use to measure how fast they’re flying

The wildlife crossing is about 50 feet wide and 320 feet long and is covered in rocks and logs.

Animals Are Using Utah's Largest Wildlife Overpass Earlier Than Expected

The state will conduct a full analysis of the bridge after three to five years, but early results are promising

The giraffe's white color comes from a genetic condition called leucism.

World's Only Known White Giraffe Now Has a GPS Tracker

The young bull used to be one of a trio of white giraffes, but the two others were found dead in March

70 percent of drowning deaths in Canada involve lake ice, and these accidents are becoming more common as climate change causes more temperature swings and moderate weather

Climate Change Causes Weaker, More Dangerous Lake Ice

Global warming causes temperature swings that leave ice weakened for days, with deadly consequences

The Blue Ring Nebula is invisible to the human eye, but telescopes can measure the ultraviolet light, which is shown here in blue.

Astronomers Crack the Case of the Blue Ring Nebula

The source of the dazzling display puzzled scientists for more than a decade

The study was small, lacked diversity in its participants and may have been affected by the volunteers’ expectations of taking the psychedelic drug. However, it suggests that this may be a fruitful path in the search for new antidepressants.

Active Ingredient in 'Shrooms' Shown to Help Treat Depression

A small study on the effectiveness of psilocybin and psychotherapy presents promising evidence

Black-and-white tegus are more resistant to cold than most reptiles because they can raise their body temperature about 50 degrees Fahrenheit above that of the environment

These Four-Foot Lizards Will Eat Anything—and They're Invading the Southeastern U.S.

Tegus first appeared in the wild of southern Florida a decade ago, but now they're in Georgia and South Carolina, too

The vaccine candidate produced by Pfizer and BioNTech is stable at minus 94 degrees Fahrenheit, so Pfizer developed a suitcase-sized box that uses dry ice to keep between 1,000 and 5,000 doses that cold for 10 days.

Why the Most Promising Covid-19 Vaccines Require Super-Cold Storage

Both Moderna and Pfizer’s vaccines contain mRNA, which must be stored in frigid conditions

Researchers from the Georgia Institute of Technology designed a peer-reviewed tool to estimate the risk of attending an event with someone infected with the coronavirus that causes Covid-19.

Five Online Tools for Evaluating Covid-19 Risk Ahead of the Holidays

Of course, the safest option is holding events virtually and skipping in-person, indoor gatherings altogether this year

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