How Many Light Years Away From the Sun Are We?

iStock.com/BlackJack3D
iStock.com/BlackJack3D

Viktor T. Toth:

You could look up the numbers easily enough: The astronomical unit (the average distance between the Earth and the Sun) is defined as exactly 149,597,870,700 meters, whereas the light year is defined as the distance covered by light in a Julian year (365.25 days), which means exactly 9,460,730,472,580,800 meters. The rest is a simple division.

But instead of typing 149597870700/9460730472580800 into Google for you (yes, Google can serve as your calculator) let me show you how you can estimate the answer to this question reasonably accurately without looking up anything or using any calculator, so long as you remember two useful numbers.

It is not hard to remember that the Earth-Sun distance is roughly 150 billion meters; that is, the digits 15 are followed by 10 zeroes.

It is also not too hard to remember that a light year is roughly 10,000 trillion meters; that is, the digit 1 is followed by 16 zeroes.

So 15 followed by 10 zeroes divided by 1 followed by 16 zeroes … that's the same as 15 followed by no zeroes at all divided by 1 followed by 6 zeroes; or 15 parts in a million. And that answer is correct within about 5.5 percent.

[The error is due mainly to the fact that the light year is overestimated by more than 5 percent, so we underestimated the ratio. "Boosting" that 15 parts in a million by an extra 5 percent gives 15.8 parts in a million, which is actually quite accurate. But at this point, you’re probably better off using a calculator after all.]

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

Why Are There 10 Hot Dogs to a Pack But Only 8 Buns?

tacar/iStock via Getty Images
tacar/iStock via Getty Images

Watching competitive eating champion Joey Chestnut cram dozens of hot dogs down his throat would make anyone crave a grilled log of processed meat this summer. But shopping for hot dogs can be a confusing experience. The dogs are typically sold in packs of 10, but the buns are sold in packs of eight. What's behind this strange dog and bun inequality?

According to the National Hot Dog and Sausage Council—yes, there is a National Hot Dog and Sausage Council—there’s a good reason for the discrepancy. For starters, distributors of hot dogs are almost always different from manufacturers of baked goods like rolls. The hot dogs are sold in packs of 10 because producers of meat (or meat-like) products selected that quantity when hot dogs started to sell at retail grocery stores in the 1940s. Oscar Mayer, which led the charge into direct-to-consumer hot dog packaging, sold hot dogs by the pound in accordance with how meat is typically priced. Having 10 dogs that weighed 1.6 ounces each seemed like the ideal distribution of weight.

Bakeries, meanwhile, have standards of their own. Buns and sandwich rolls are usually sold eight to a pack because the baking trays for the elongated buns are typically sized to fit that number. Two sets of four buns come off the tray, which is the reason why buns are often still attached to one another when you open a bag.

These standards were created independently of one another: Bakeries weren’t too preoccupied with hot dogs when they were settling on a four-roll tray standard, and hot dog manufacturers weren’t thinking about how difficult it would be for bakeries to break from their conveyor system to offer 10 buns to a pack.

It can be frustrating if you buy just one or two packages of each, but if you’re hosting a big enough party, the uneven number doesn’t matter. You just need to buy five packages of buns and four packages of hot dogs to have 40 matching pairs. No complicated calculations required.

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When Are the Dog Days of Summer?

Dorottya_Mathe/iStock via Getty Images
Dorottya_Mathe/iStock via Getty Images

The official “dog days” of summer begin on July 3 and end on August 11. So how did this time frame earn its canine nickname? It turns out the phrase has nothing to do with the poor pooches who are forever seeking shade in the July heat, and everything to do with the nighttime sky.

Sirius, the Dog Star, is the brightest star in the sky. The ancient Greeks noticed that in the summer months, Sirius rose and set with the Sun, and they theorized that it was the bright, glowing Dog Star that was adding extra heat to the Earth in July and August.

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