20 Weird Facts About Earth to Remind You Why It’s Amazing

“Within uncertainty, the temperature at the center of the Earth is the same as the temperature at the surface of the sun (5800 K),” Caltech geochemist Paul Asimow tells Popular Mechanics. At about almost 10,000 degrees Fahrenheit, that’s hot.

In total, Earth generates as much as 40 terawatts of heat, half of which comes from radioactive decay in its core, according to a 2011 study. Scientists measured particles called antineutrinos that streamed up from Earth’s core and found that half of Earth’s heat is generated through the radioactive decay of certain elements.

Tom Crafford, a Mineral Resources Program Coordinator at the U.S. Geological Survey (USGS) tells Popular Mechanics: “Most of the internal heat that keeps Earth a living, vibrant planet comes from the radioactive breakdown of elements like thorium, uranium, and potassium.”

“The sediments underlying Earth’s oceans are home to approximately 2.9 x 10^29 microorganisms, existing at depths as great as 2.5 km below the seafloor. The majority of this deep subseafloor biosphere grows extremely slowly relative to life in the surface world, with estimates of cell division once every 10 to 1000+ years,” Caltech geobiologist Victoria Orphan tells Popular Mechanics.

Scientists are finding new sources of microbial life deeper and deeper below the seafloor than ever before. In March 2020, a team of scientists revealed that they had found traces of bacteria (try 10 billion bacterial cells) in rocks 400 feet below the seafloor—deeper than ever before.

“Mosses live on the surface soils in deserts all across the world. A cool thing about moss is that they have the ability to capture water straight out of the air using these specialized structures that look like little hairs coming out of their leaves—called awns,” USGS research ecologist Sasha Reed, tells Popular Mechanics. “In the dry places that these mosses live, this is a pretty cool trick!”

“Each culture has its own version of ‘earthquake weather’ to rationalize when and where an earthquake will hit,” seismologist Dr. Lucy Jones of Caltech tells Popular Mechanics. “Earthquakes are below the surface and need a constant fault to happen and this has nothing to do with weather.”

“We are headed toward a two-foot sea level rise by the end of this century,” climate scientist Tapio Schneider of Caltech tells Popular Mechanics. “Consequences from a one- to two-foot sea level rise could mean severe threats to low-lying island nations, loss of narrow, shallow beaches, and a demise of marine ecosystems.”

“If you bring all water droplets in clouds to the surface, you would cover Earth with a liquid film no thicker than a human hair,” Schneider of Caltech tells Popular Mechanics. “And yet, this tiny amount of water makes the difference between cool overcast summer days and warm clear days. And it is immensely important for climate. On average, clouds cool Earth by 13 degrees Fahrenheit relative to what global temperatures would be without clouds.”

“How much global warming we get crucially depends on whether we get more or fewer clouds as the climate warms,” Schneider says. “Climate models do not agree on the answer, because simulating clouds and the tiny amount of water in them is hard. At Caltech, we are working on using AI to make climate models and their cloud simulations better, to get more precise answers about how climate will change.”

“Planet Earth has an estimated age of 4.5 billion years,” Jeremiah P. Ostricker, senior research scholar at Princeton University, tells Popular Mechanics. “Homo Sapiens has been around for at most 450,000 years, that is 1/10,000 the age of the planet. And then, more recently, we spread over the whole globe in 1/100,000 of the age of the planet.”

Unlike other planets, no real historical data can be found on the person (or group) that named our planet “Earth.” The term Earth comes from Old English and High Germanic, and it is the only planet not named after a Greek or Roman god.

“Earth is a giant heat engine. Heat from the Sun is absorbed where it is warm (the low latitudes and the surface) and heat is radiated as infrared where it is cold (the higher latitudes and the atmosphere),” Andy Ingersoll, a planetary scientist at Caltech, tells Popular Mechanics. “The work of the heat engine goes into the kinetic energy of winds and storms.”

“The Earth is not a very efficient heat engine,” says Ingersoll. “The temperature difference between the warm parts and the cold parts is a few tens of K, so the theoretical Carnot efficiency is about 10 percent. But most of that is wasted by the warm parts radiating their heat to the cold parts, creating entropy. The heat engine is about one percent efficient in generating kinetic energy, but that creates more entropy when the winds dissipate.”

“The boundary between Earth’s mantle and core is roughly 3,000 kilometers below our feet—a little less than the total length of America’s ‘Mother Road,’ Route 66,” seismologist Jennifer Jackson of Caltech tells Popular Mechanics. “Thought to be a simple interface between solid rocks and liquid iron-rich metal, this remote region is almost as complex as Earth’s surface.”

“Impossible to reach in person, geophysical and experimental studies of this distant region reveal a fascinating landscape of chemical and structural complexity that influence what’s happening on Earth’s surface,” Jackson says. “For example, the complex dynamics of Earth’s core-mantle boundary affects Earth’s protective geomagnetic field and the motion of tectonic plates.”

“We’ve never seen anything larger than 9.5 and it was longer than the state of California,” says Jones. “It would be theoretically impossible to have a magnitude 13 earthquake since it would require a fault bigger than the Earth.”

“Earthquakes can happen over 400 miles below the Earth’s surface, and be felt literally on the other side of the Earth,” seismologist Zhongwen Zhan of Caltech tells Popular Mechanics. “In 2013, a magnitude 8 occurred near the Kuril Islands at about 400 miles depth. People in Australia felt the event!”

Scientists discovered the first hole in the ozone layer, located directly above Antarctica, in 1985. The Montreal Protocol of 1987 was the first plan approved by every country in the United Nations, and focused on the restriction of chlorofluorocarbons (CFCs that emitted ozone-destroying chlorines).

“The number of microbes in a teaspoon of soil is estimated to be roughly equivalent to the number of humans currently living in Africa (one billion),” biologist Dianne Newman of Caltech tells Popular Mechanics.

Planet Earth is shaped more like an oblate spheroid which looks like a flatter circle. But it’s definitely not flat.

“The tides are the small differences between the gravitational pull of the moon and the Sun and the centrifugal forces in the opposite directions. The tides on Earth are strongest when the three bodies are in a line, which happens near full moon and new moon. Then the Earth is being stretched out along that line,” says Ingersoll.

“The ocean responds the most, but even the solid Earth responds to the tidal forces,” he says. “The response consists of water moving in the oceans and rocks moving underground, both of which dissipate kinetic energy. The net result is that the Earth is spinning down—the day is getting longer.”

“Groundwater pumping can cause significant land surface subsidence—enough so that it can be ‘seen’ from space,” Sheets says. Researchers use satellites and GPS stations to track how far the Earth has sunk.

Earth is teeming with viruses. There are an estimated 10 nonillion individual viruses on the planet. That’s “enough to assign one to every star in the universe 100 million times over,” Katherine J. Wu writes in National Geographic.