7 Shining Facts About the Sun


Isaac Asimov described the solar system as the Sun, Jupiter, and debris. He wasn't wrong—the Sun is 99.8 percent of the mass of the solar system. But what is the giant ball of fire in the sky? How does it behave and what mysteries remain? Mental Floss spoke to Angelos Vourlidas, an astrophysicist and the supervisor of the Solar Section at Johns Hopkins University Applied Physics Laboratory, to learn what scientists know about the Sun—and a few things they don't.


The Sun is so incomprehensibly big that it's almost pointless to bother trying to imagine its size. Our star is about 860,000 miles across. It is so big that 1.3 million Earths could fit inside of it. The Sun is 4.5 billion years old, and should last for another 6.5 billion years. When it faces the final curtain, it will not go supernova, however, as lacks the mass for such an end. Rather, the Sun will grow to a red giant—destroying the Earth in the process, if we last that long, which we won't—and then contract down to become a white dwarf.

The Sun is 74 percent hydrogen and 25 percent helium, with a few other elements thrown in for flavor, and every second, nuclear reactions at its core fuse hundreds of millions of tons of hydrogen into hundreds of millions of tons of helium, releasing the heat and light that we love so very much.


The Sun rotates, though not quite the same way as a terrestrial planet like the Earth. Like the gas and ice giants, the Sun's equator and poles complete their rotations at different times. It takes the Sun's equator 24 days to complete a rotation. Its poles poke along and rotate every 35 days. Meanwhile, the Sun actually has its own orbit. Moving at 450,000 miles per hour, the Sun is in orbit around the center of the Milky Way galaxy, making a full loop every 230 million years.


The solar corona as captured every two hours for four days. Red is cool (~80,000°F), while yellow is hot (~2,800,000°F).Angelos Vourlidas, JHU/APL

The Sun's temperatures leave astrophysicists puzzled. At its core, it reaches a staggering 27,000,000°F. Its surface is a frosty 10,000°F, which, as NASA notes, is still hot enough to make diamonds boil. Here's the weird part, though. Once you get into the higher parts of the Sun's corona, temperatures again rise to 3,500,000°F. Why? Nobody knows!


If you saw the total solar eclipse earlier this year, you saw the Sun turn black, ringed by a shimmering white corona. That halo was part of the Sun's atmosphere. And it's a lot bigger than that. In fact, the Earth is inside of the Sun's atmosphere. "It basically goes as far away as Jupiter," Vourlidas tells Mental Floss. The Sun is a semi-chaotic system. Every 100 years or so, the Sun seems to go into a small "sleep," and for two or three decades, its activity is reduced. When it wakes, it becomes much more active and violent. Scientists are not sure why that is. Presently we are in one of those solar lulls.


The Sun lacks a solid core. At 27,000,000°F, it's all plasma down there. "That's where most of the heavy elements like iron and uranium are created—at the cores of stars," Vourlidas says. "When the stars explode, they are released into space. Planets form out of that debris, and that's where we get the same iron in our blood and the carbon in our cells. They were made in some star." Not ours, obviously, but a star that exploded in our neighborhood before our Sun was born. Other elements created from the cores of stars include gold, silver, and plutonium. That is what Carl Sagan meant when he said that we are children of the stars.


The ability to predict solar storms is the holy grail for astrophysicists who study the Sun. During a coronal mass ejection, a billion tons of plasma material can be blown from the Sun at millions of miles per hour. The eruptions carry around 300 petawatts of energy—that's 50,000 times the amount of energy that humans use in a single year. As the structures travel from the Sun, they expand, and when they hit the Earth, a percentage of their energy is imparted. Those impacts can create havoc. Spacecraft are affected, airliners receive surges of x-rays, and the energy grid can be disrupted—one day perhaps catastrophically so. "Our models say it can happen every 200 years," says Vourlidas, "but the Sun doesn't know about our models."

The last such strike on the Earth is believed to have occurred in 1859. The telegraph system collapsed, but the effect on society was minimal overall. (The widespread use of electric lighting and the first power grids were still decades away.) If the Earth were to sustain a similar such destructive event today, the effects might be devastating. "It is the most violent phenomenon in our solar system," Vourlidas explains. "We need to know when such an amount of plasma has left the Sun, whether it will hit the Earth, and how hard it is going to slap us." Such foresight would allow spacecraft to power down sensitive instruments and power grids to switch off where necessary, among other things.


Wind moving off of the Sun in visible light. If you were in a spaceship and didn't melt, that's what you would see. The zooming effect simulates what an imager on the Parker Solar Probe will see. Angelos Vourlidas, JHU/APL

Next year, NASA will launch the Applied Physics Laboratory's Parker Solar Probe to "kiss" the Sun. It will travel to within 4 million miles of our star—the closest we've ever come—and will study the corona and the solar wind. "At the moment, the only way we understand that system is by seeing what the properties of the wind are at Earth, and then trying to extrapolate back toward the Sun," says Vourlidas. "It's an indirect exercise. But the probe will measure the wind—how fast it is, how dense, what is the magnetic field—across multiple locations as it orbits the Sun." Once scientists get those measurements, theorists will attempt to devise new models of the solar wind, and ultimately help better predict solar storms and space weather events.

Editor's Note: This post has been updated. 

Kodak’s New Cameras Don't Just Take Photos—They Also Print Them

Your Instagram account wishes it had this clout.
Your Instagram account wishes it had this clout.

Snapping a photo and immediately sharing it on social media is definitely convenient, but there’s still something so satisfying about having the printed photo—like you’re actually holding the memory in your hands. Kodak’s new STEP cameras now offer the best of both worlds.

As its name implies, the Kodak STEP Instant Print Digital Camera, available for $70 on Amazon, lets you take a picture and print it out on that very same device. Not only do you get to skip the irksome process of uploading photos to your computer and printing them on your bulky, non-portable printer (or worse yet, having to wait for your local pharmacy to print them for you), but you never need to bother with ink cartridges or toner, either. The Kodak STEP comes with special 2-inch-by-3-inch printing paper inlaid with color crystals that bring your image to life. There’s also an adhesive layer on the back, so you can easily stick your photos to laptop covers, scrapbooks, or whatever else could use a little adornment.

There's a 10-second self-timer, so you don't have to ask strangers to take your group photos.Kodak

For those of you who want to give your photos some added flair, you might like the Kodak STEP Touch, available for $130 from Amazon. It’s similar to the regular Kodak STEP, but the LCD touch screen allows you to edit your photos before you print them; you can also shoot short videos and even share your content straight to social media.

If you want to print photos from your smartphone gallery, there's the Kodak STEP Instant Mobile Photo Printer. This portable $80 printer connects to any iOS or Android device with Bluetooth capabilities and can print whatever photos you send to it.

The Kodak STEP Instant Mobile Photo Printer connects to an app that allows you to add filters and other effects to your photos. Kodak

All three Kodak STEP devices come with some of that magical printer paper, but you can order additional refills, too—a 20-sheet set costs $8 on Amazon.

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How to See August’s Full Sturgeon Moon

It'd be pure lunacy to skip an opportunity to see this beauty.
It'd be pure lunacy to skip an opportunity to see this beauty.
mnchilemom, Flickr // CC BY 2.0

This summer has been an especially exciting time for avid sky-gazers—the NEOWISE comet flew close to Earth in mid-July, and the ongoing Perseid meteor shower is gearing up for its peak around August 11. Though full moons aren’t quite as rare, the sight of a glowing white orb illuminating the night is still worth a glance out your window.

When Is August’s Full Moon?

As The Old Farmer’s Almanac reports, the eighth full moon of 2020 will reach its peak at 11:59 a.m. EST on Monday, August 3. If that’s daytime where you live, you’ll have to wait for the sun to set that night, or you can catch it the night before—Sunday, August 2.

Why Is It Called a Sturgeon Moon?

Each month’s full moon has a nickname (or multiple nicknames), usually of folk origin, that coincides with certain plant, animal, or weather activity common at that time of year. January’s full moon, for example, was named the “wolf moon” because wolves were said to howl more often during January. June’s “strawberry moon” occurred when strawberries were ripe and ready to be picked.

Since people caught an abundance of sturgeon—a large freshwater fish that’s been around since the Mesozoic era—in the Great Lakes and Lake Champlain during this part of summer, they started calling August’s full moon the sturgeon moon. It has a few lesser-known monikers, too, including the “full green corn moon” (a nod to the approaching harvest season), and the slightly wordy “moon when all things ripen.”

[h/t The Old Farmer’s Almanac]