Does the Sun Rotate Like the Earth?

iStock/FooAggieband
iStock/FooAggieband

Jack Fraser:

No it does not.

The Sun does rotate, but it does not rotate like the Earth.

That's because, despite its fluid center and atmosphere, the Earth rotates (more or less) like a rigid body, all of it rotating at (again: more or less) the same speed. One day is 24 hours, no matter where on—or in—the Earth you are.

The Sun, however, is manifestly not a rigid body. It is a gigantic ball of superheated plasma, which means that different parts of the sun rotate at different rates.

The equator of the Sun completes a full rotation once every 24.5 days, while the poles take almost 38 days to complete a rotation.

It can be a little bit difficult to spot with the naked eye, but you can just about appreciate the difference in speeds of the sunspots in this video:

Modern helioseismology has also provided significant evidence that the rate of rotation inside the Sun also varies hugely—so the surface can rotate up to 40 percent faster than the material halfway between the core and the surface.

Hence, the sun does rotate, but nothing like the Earth.

This post originally appeared on Quora. Click here to view.

How Did 6 Feet Become the Standard Grave Depth?

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iStock

It all started with the plague: The origins of “six feet under” come from a 1665 outbreak in England. As the disease swept the country, the mayor of London literally laid down the law about how to deal with the bodies to avoid further infections. Among his specifications—made in “Orders Conceived and Published by the Lord Mayor and Aldermen of the City of London, Concerning the Infection of the Plague”—was that “all the graves shall be at least six feet deep.”

The law eventually fell out of favor both in England and its colonies. Modern American burial laws vary from state to state, though many states simply require a minimum of 18 inches of soil on top of the casket or burial vault (or two feet of soil if the body is not enclosed in anything). Given an 18-inch dirt buffer and the height of the average casket (which appears to be approximately 30 inches), a grave as shallow as four feet would be fine.

A typical modern burial involves a body pumped full of chemical preservatives sealed inside a sturdy metal casket, which is itself sealed inside a steel or cement burial vault. It’s less of a hospitable environment for microbes than the grave used to be. For untypical burials, though—where the body isn’t embalmed, a vault isn’t used, or the casket is wood instead of metal or is foregone entirely—even these less strict burial standards provide a measure of safety and comfort. Without any protection, and subjected to a few years of soil erosion, the bones of the dearly departed could inconveniently and unexpectedly surface or get too close to the living, scaring people and acting as disease vectors. The minimum depth helps keep the dead down where they belong.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This article originally appeared in 2012.

What's the Difference Between Apple Juice and Apple Cider?

iStock/Alter_photo
iStock/Alter_photo

In a time before pumpkin spice went overboard with its marketing, people associated fall with fresh apples. Crisp and fresh, they practically beg to be crushed and pulped into liquid. But what’s the difference between apple juice and apple cider?

According to the state of Massachusetts, home to a variety of apple-picking destinations, both apple juice and apple cider are fruit beverages. But apple cider is raw, unfiltered juice—the pulp and sediment are intact. To make cider, the apples are ground into an applesauce-like consistency, then wrapped in cloth. A machine squeezes the layers and strains out the juice into cold tanks. That’s the cider that ends up on store shelves.

Apple juice, on the other hand, takes things a step further—removing solids and pasteurizing the liquid to lengthen its shelf life. It’s typically sweeter, possibly with added sugar, and may lack the stronger flavor of its relatively unprocessed counterpart. It’s also often lighter in color, since the remaining sediment of cider can give it a cloudy appearance.

But that’s just the Massachusetts standard. Each state allows for a slight variation in what companies are allowed to call apple cider versus apple juice. The cider may be pasteurized, or the cider and juice may actually be more or less identical. One company, Martinelli’s, states in its company FAQ that their two drinks are the same in every way except the label: "Both are 100 percent pure juice from U.S. grown fresh apples. We continue to offer the cider label since some consumers simply prefer the traditional name for apple juice."

The US Apple Association, a nonprofit trade organization that represents growers nationwide, indicates that apple juice can be made from concentrate, which is why you might see water as the first ingredient on the label. Generally, cider is the hard stuff: Crushed apples with minimal processing. Because it can ferment, it's usually found refrigerated. Apple juice can often be found elsewhere in stores, where it can remain stable.

Which you should buy comes down to personal preference. Typically, though, recipes calling for apple cider should use apple cider. Processed juice may be too sweet an ingredient. And you can always try making a pumpkin spice hot apple cider, although we may stop talking to you if you do.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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