8 Things You Need to Know About Earth

It's probably best that we don't think too much about the Earth. After all, it's a tiny orb spinning more than 1000 mph at the equator while simultaneously zipping through space at 67,000 miles per hour. It circles a mysterious, 10,000°F fusion reactor that's more than 100 times its size, and spends most of its orbit narrowly (in a cosmic sense) avoiding collisions with giant chunks of rock that could practically wipe its surface clean. But if you're feeling brave, here are a few things you might not know about Earth. Mental Floss spoke to Josh Willis, a climate scientist at NASA's Jet Propulsion Laboratory, about the planet we call home.

1. EARTH, BY THE NUMBERS.

The Earth orbits the Sun at approximately 93 million miles. As you probably know, at this distance it takes one year for the Earth to complete a revolution, and 24 hours to complete one rotation. The surface of the Earth has temperatures ranging from -126°F to 136°F. The planet is about 7900 miles in diameter (though the deepest we've ever drilled is 7.6 miles). There are 332,519,000 cubic miles of water on the planet, which is enough that, if the water broke from the Earth and organized itself into a sphere, it would have a diameter of 860 miles—about 40 percent that of the Moon.

2. SEEING IS BELIEVING.

The first photograph of Earth from space was taken in 1946. It's a grainy, black-and-white shot of a tiny slice of our world, curved with the ink of space as a backdrop. In 1960, weather satellites began sending photographs back to Earth, images that were still hideously deformed but scientifically valuable, especially for meteorologists, who now had stunning views of cloud systems from which to work. NASA's ATS-III satellite in 1967 returned the first color images of the full Earth. Now at last, we could see our living world, ringed in space and wrapped in billowing clouds.

On Christmas Eve, 1968, Apollo 8 astronaut William Anders sent back "Earthrise," a now-iconic photograph of a fragile cerulean orb rising over the lunar surface. But the most famous photograph of the Earth, by far, was taken about four years later, on December 7, 1972: the "Blue Marble." You've probably seen it countless times, enough that when you think of the Earth, that's what you think of. You may be less familiar with how astronaut Harrison Schmitt described the sight to Mission Control: "I'll tell you, if there ever was a fragile-appearing piece of blue in space, it's the Earth right now."

3. WE HAVE A NATURAL SATELLITE.

The Earth is the first planet, moving outward from the Sun, that possesses a moon. We call our moon "The Moon" (which will be a real headache centuries from now, when we've colonized the solar system). Every 27.32 days, the Moon completes an orbit of the Earth, which is why it has phases. When the Earth is between the Sun and the Moon, we see the Moon in full illumination (a round orb). As it circles the Earth, less and less of its visible surface is illuminated, until at last the Moon is between the Sun and the Earth. At that point, the "far side" of the Moon is in full illumination, and from our perspective, the Moon is receiving no light at all. The cycle then repeats itself, with more of its disc being illuminated as the month elapses, until it is again full. Because the length of the Moon's orbit is just shy of a month, every so often a month (which, itself, derives from the word "moon") has two full Moons, the second of which is colloquially called a Blue Moon.

The moon does spin, but in synchronous rotation with the Earth. In other words, it spins at the same speed as its orbit. As a result, the Earth only ever gets to see one side of our only natural satellite. The best guess for the origin of the Moon involves an object the size of Mars smashing into the Earth 4.5 billion years ago, sending debris into space. This debris organized itself into a molten form of the alabaster orb we know and love. Within 100 million years, an early crust had begun to form. Today, the Moon influences the tides of the ocean and eases our axial wobble, keeping things (more or less) nice and stable—a perfect condition for life.

4. LIFE FINDS A WAY …

When it comes to life, there are a lot of maybes in the solar system. Maybe Mars supported life billions of years ago. Maybe Europa is teeming with life today. The problem is that there is no evidence anywhere of anything that wiggles, walks, or swims … except for one place. Earth is the only body in the universe known to harbor life. And it has been tough going! Four billion years ago, the Earth's surface was sterilized during the Late Heavy Bombardment, when asteroids pilloried the inner solar system. To get some idea of what things must have been like during the LHB, look at the Moon. Most of its craters were formed during that time. Life survived on Earth in large part thanks to the hydrothermal vents at the bottom of the ocean.

There have been five mass extinctions on Earth, the worst of which (the Permian-Triassic, or "P-T Event") was 250 million years ago, wiping out 96 percent of sea species and nearly three-quarters of land vertebrates. Sixty-six million years ago, the Chicxulub impact wiped out 75 percent of all life, and ended the reign of the dinosaurs. Things recovered nicely, though, and today, biologists think there are 8.7 million species of life on Earth. That's not bad considering the universe's apparent hostility to life, and makes what we have going here all the more special and worth preserving. And we'd better get on it: Many scientists argue that we're in the midst of a sixth mass extinction—and we can only partially blame it on cats.

5. … BUT WE'RE DOING A POOR JOB OF PRESERVING IT.

"Global warming is real, it's caused by people, and it's a big problem," Willis told Mental Floss. "Every year the impacts of human-caused climate change get bigger and bigger, and are felt more and more across the planet." We feel the effects of climate change today, but the worst is yet to come, both in terms of economic and social disruption. "Right now we have a choice about what kind of planet we want to have in the future. And the choice is: Do we want to continue to burn fossil fuels and heat up the Earth, or do we want to try and stabilize our climate and keep it more or less like we've had it for the last 10,000 years?"

6. THE WATER IS RISING.

Carl Sagan once observed that, to scale, the Earth's atmosphere is about as thick as the gloss coating on a globe. Our oceans, meanwhile, make Earth the only known planet with stable water at its surface. (Icy moons like Europa and Enceladus have subsurface oceans of liquid water, and Titan, in addition to a possible subsurface ocean of water, has vast lakes of liquid methane covering its surface.)

The problem is, we're causing those water levels to rise. NASA's Jason-3 spacecraft measures the height of the ocean with 1-inch accuracy. Every 10 days, it collects data on the entire ocean, revealing details about such things as ocean currents and how they change, tilts in the ocean's surface, and the average volume of the ocean. "The oceans are growing for two reasons," says Willis. "One is because they absorb heat trapped by the greenhouse gases, and the other is that the ice in places like Greenland and Antarctica and tiny glaciers all across the planet are all melting and adding extra water to the oceans. And so this satellite measures these things combined, and in a way it's really taking the pulse of our planet."

A decade ago, the ice sheets in Greenland and Antarctica were thought of as stable. They are the last remaining ice sheets that cover huge land masses, and today they are disappearing. In 50 years, their melting will be the dominant source of global sea level rise. "Every time a big discovery is made," says Willis, "it seems like the picture is worse than we thought it was. The possibility for really rapid ice loss and rapid sea level rise is greater than we thought."

7. THERE MAY BE ANSWERS UNDERWATER.

The oceans remain a giant unknown for scientists. Knowing more about them would answer many of our questions about life and the life of the Earth. "Two-thirds of the planet is covered with water, and you can't see through it. And you can't shoot microwaves through it, and radio waves, and all the other kinds of things that we use even to measure other planets," Willis says. "If you probe the ocean, there are still a lot of big mysteries down there."

To understand how oceans really work would explain, for example, where the heat from global warming is going. Though the oceans absorb 95 percent of the heat trapped by greenhouse gases, it's still a mystery where that heat energy actually goes. Similar questions exist as to how the oceans interact with ice sheets.

Considering the stakes, it seems like an intense study of the Earth and its oceans is in order. And yet the same people who claim there isn't enough evidence to explain climate change want to slash the budgets of missions designed to find the requested evidence. Among the missions set to be killed are the PACE satellite, over a decade in development and designed to study the interaction of the ocean and the atmosphere, and the CLARREO pathfinder mission, which would cut the time necessary to predict climate change in half. (An extra 20 years to prepare for climate change would save the world $10 trillion.)

8. THERE IS STILL HOPE FOR OUR PALE BLUE DOT.

But it will take a concerted effort to change our behavior—before it's too late. "We think of global warming as something that happens in our cities, and it is happening there, but really 95 percent of the heat that's being trapped is going in the oceans. And I don't think people realize that. It just seems like, well, we're getting the brunt of global warming here in Los Angeles—but that's not true, really. It's the sea life and the oceans that are getting the brunt of the change," says Willis.

"One thing we should keep in mind is that all hope is not lost," he continues. "We are beginning to see changes in our economy, we're beginning to see the growth of renewable energy, and the strong desire to move to a fuel source that doesn't cook us, and I think that's a good thing. A lot of it happens at local and state levels now, but it's beginning to have an impact for real around the world."

Two Harvard Scientists Suggest 'Oumuamua Could Be, Uh, an Alien Probe

ESO/M. Kornmesser
ESO/M. Kornmesser

An odd, cigar-shaped object has been stumping scientists ever since it zoomed into our solar system last year. Dubbed 'Oumuamua (pronounced oh-MOO-ah-MOO-ah), it was first seen through the Pan-STARRS 1 telescope in Hawaii in October 2017. 'Oumuamua moved at an unusually high speed and in a different kind of orbit than those of comets or asteroids, leading scientists to conclude that it didn't originate in our solar system. It was the first interstellar object to arrive from somewhere else, but its visit was brief. After being spotted over Chile and other locales, 'Oumuamua left last January, leaving lots of questions in its wake.

Now, two researchers at Harvard University bury a surprising suggestion in a new paper that analyzes the object's movement: 'Oumuamua could be an alien probe. Sure, why not?

First, astrophysicists Shmuel Bialy and Abraham Loeb argue that 'Oumuamua is being driven through space by solar radiation pressure, which could explain its uncharacteristic speed. But for that theory to work, they calculate that the object must be unusually thin. Bialy and Loeb then analyze how such a slender object might withstand collisions with dust and gases, and the force of rotation, on its interstellar journey.

Then things get weird.

"A more exotic scenario is that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization," they write [PDF]. They suggest that ‘Oumuamua could be be a lightsail—an artificial object propelled by radiation pressure—which also happens to be the technology that the Breakthrough Starshot initiative, of which Loeb is the advisory committee chair, is trying to send into space. "Considering an artificial origin, one possibility is that 'Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” they write.

Their paper, which was not peer-reviewed, was posted on the pre-print platform arXiv.

Loeb is well known for theorizing about alien tech. He previously suggested that intense radio signals from 2007 could be the work of aliens who travel through space on solar sails. However, Loeb acknowledged that this theory deals more with possibility than probability, The Washington Post noted. “It’s worth putting ideas out there and letting the data be the judge,” Loeb told the paper last year.

[h/t CNN]

A Team of Young Women Wants to Send Kyrgyzstan's First Satellite to Space

José Furtado y Antel, Wikimedia Commons // CC0 1.0
José Furtado y Antel, Wikimedia Commons // CC0 1.0

Kyrgyzstan is one of 123 countries that doesn't have a national space agency. That could soon change, thanks to a group of young programmers and engineers taking the matter into their own hands.

As The Next Web reports, the Kyrgyz Space Program is made up of 12 women ranging in age from 17 to 25 years old. They met in 2017, when journalist and TED fellow Bektour Iskender started a free course in his home country of Kyrgyzstan teaching young women there how to build robots and satellites.

The team has since made it its mission to build a cube satellite (CubeSat)—a smaller type of satellite that costs about $150,000 to put together. If they are able to construct the spacecraft, launch it into orbit, and send it to the International Space Station as planned, the project will mark the first time Kyrgyzstan has sent a satellite into space.

The Kyrgyz Space Program now meets twice a week in the offices of Kloop, a media outlet that's known for its support of feminist causes in a country where women still have a long way to go to reach parity. Even as more women start to get involved in Kyrgyzstan's politics, domestic violence, child marriage, and bride kidnappings are still rampant.

In order to accomplish their goal of sending a Kyrgyz satellite to orbit, the program has launched a crowdfunding campaign. Reaching the $2500-a-month marker means they can construct the CubeSat with guidance from the team who launched Lithuania's first satellite. If they reach the $10,000-a-month threshold, they will be able to send the CubeSat to the International Space Station. You can join the 120 people who've already supported their Patreon page by pledging today.

[h/t The Next Web]

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