# Driving to another planet (please check my math)

**URL:** <https://boards.straightdope.com/t/driving-to-another-planet-please-check-my-math/286683>\
**Category:** Miscellaneous and Personal Stuff I Must Share\
**Created:** [January 26, 2005, 2:02am UTC](https://boards.straightdope.com/t/driving-to-another-planet-please-check-my-math/286683 "2005-01-26T02:02:50Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Llama\_Llogophile](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@Llama\_Llogophile](https://boards.straightdope.com/u/Llama_Llogophile)\
**Post date:** [January 26, 2005, 2:02am UTC](https://boards.straightdope.com/t/driving-to-another-planet-please-check-my-math/286683/1 "2005-01-26T02:02:50Z")

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I’m giving a talk to some kids tomorrow about astronomy, and I wanted to give an idea of the distances we’re talking about. I researched lots of ways to demonstrate the scale of the solar system, but these are little kids, and none seemed appropriate.

So I had the idea to put it to them in what are hopefully familiar terms. Assume we are travelling on a school bus, and we’ve got the sucker cranked up to 100 mph. Using the average distances of the planets from the sun, I came up with these numbers for driving time to the planets:

```
                Point to point (years) : Cumulative               

```

Mercury 41 : 41  
Venus 35 : 76  
Earth 29 : 106  
Moon 99.52 (days)   
Mars 55 : 161  
Jupiter 390 : 551  
Saturn 459 : 1011  
Uranus 1025 : 2036  
Neptune 1153 : 3189  
Pluto 999 : 4189

This really blows me away. I had a hard time deciding to where to post this. I mean, it hardly seems mundane and pointless…

And could someone please check my math for me? I got my data from the JPL web site. They give one astronomical unit as 92,955,820 miles. Driving at 100mph I figure that distance to take 106.1139498 years. I used that figure, rounding off the decimals to make the other calculations (which is why they are slightly off - all those decimals eventually add up). Average distance to the moon from earth was listed as 238,855 miles. That would take just over 99 days. I fudged that, and called it a third of year.

Do I have it close enough to right to make my point?

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**Author:** ![Podkayne](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Podkayne](https://boards.straightdope.com/u/Podkayne)\
**Post date:** [January 26, 2005, 2:31am UTC](https://boards.straightdope.com/t/driving-to-another-planet-please-check-my-math/286683/2 "2005-01-26T02:31:04Z")

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Fred Hoyle used to say, “Space isn’t remote at all. It’s only an hour’s drive away if your car could go straight upwards.” Your project reminds me of that. 🙂

My only criticism is that the average length of a year is 365.24 days (remember leap years!), and it looks like you used 365.

Also, you might want to remind your students that the planets _never_ line straight up, and it would take _even longer_ to take your tour of the Solar System if you consider that the planets are all in different parts of their orbits.

Otherwise, looks good to me. (Confession: I only spot-checked your math Pluto, Mercury, and Jupiter. Just by eyeball the rest looks good.)