OK Google, How Big is a Light-year

A while back, I was sitting outside on the deck at night working and, while
waiting for a build, I was looking at the stars. Then I got curious, how
big a is light-year? OK, I can look it up and it’s ~5.9 x 10¹² miles. So more
miles than the US Government’s annual budget in dollars. I can’t comprehend either.

At the time I started playing with Google searches, but I wanted to try using only Google Assistant.

OK Google, how big is a grain of sand?

Sand ranges in size from 2–64mm. Close enough, call it 1mm for really fine sand. [Edit: I misunderstood Google: 2–64mm is the range for gravel, and sand is smaller than that. So 1mm for very coarse sand. Thanks, Johnathan, for the correction.]

OK Google, what is the diameter of the Earth in millimeters?

12.742 x 10⁹ mm. There’s our scale factor.

OK Google, how big is a light-year in millimeters?

9.461 x 10¹⁸ mm.

OK Google, what is 9.4 x 10¹⁸ / 12.742 x 10⁹?

3 x 10²⁷. Wrong. It got the parens wrong.

OK Google, what is 9.461 / 12.742?

Some answer in Quora. Nope.

OK Google, calculate 9.461 / 12.742

0.743 x 10⁹ or 743 million. Doing 18–9 in my head is easier than trying to figure out how to speak the parens to Google.

OK Google, convert 7.43 x 10⁸ mm to miles

461.7 miles. This took a couple of tries and I had to phrase it this way. Using “743 million millimeters” seemed to confuse it. But there we have it, if the Earth was 1mm in diameter, one light-year is 462 miles, about an 8 hour drive by car.

OK Google, what is the nearest star?

It correctly said Proxima Centauri is the nearest neighbor to the Sun, not the snarky (but correct) answer of “the Sun”. Some phrasings return Alpha Centauri, of which Proxima Centauri is the nearest of the three small stars.

OK Google, how far is Proxima Centauri?

4.24 light-years from Earth

OK Google, calculate 4.24 * 462

1959 (miles).

OK Google, how far is it from Austin, TX to Boston, MA?

1956.7 miles driving distance.

So there we have it. If the Earth was 1mm in diameter, somewhere in size between coarse sand and small gravel, the nearest star system, Alpha Centauri, is road trip from Austin to Boston with only small detours to get food and charge the batteries. That’s a long trip.

This kind of exercise always highlights to me the vast emptiness of space. Think about it: there is a bit of tracked-in dirt in Austin, TX and nothing until three small areas of dirt in Boston, MA!