the edge of the visible The universe is about 270,000,000,000,000,000,000 miles away.
If you were driving at a constant 65 miles per hour, it would take 480,000,000,000,000,000,000 – that’s 4.8 x 10¹⁷ – years to get there, or 35 million times the current age of the universe.
This would be a dangerous road trip. I don’t mean because of the space stuff – we don’t worry about all that – but because driving itself is very dangerous. In the United States, a middle-aged driver suffers one fatal accident for every 100 million miles. If someone built a highway outside the solar system, most drivers wouldn’t be able to get past the asteroid belt. Truck drivers, who are used to driving long distances on highways, have a lower crash-per-mile rate than other drivers, but they are less likely to make it to Jupiter.
Based on national collision rates, the odds of a driver traveling 46 billion light-years without a collision would be about 1 in 10¹⁰^¹⁵. That’s about the same as the probability of a monkey with a typewriter typing the entire Library of Congress, no typos, 50 times in a row.. You’ll need a self-driving car, or at least one that has one of those alarms that warn you if you veer off your lane.
The trip will take a lot of fuel. At 33 miles per gallon, it would take a moon-sized ball of gasoline to reach the edge of the universe. (As of 2021, NASA’s New Horizons spacecraft has traveled about five billion miles on a budget of about $850 million, which comes out to 17 cents per mile—much like the cost of gas and snacks on a road trip.) You were going to do about 30 quintillion oil changes, which would require a container of motor oil the size of the Arctic Ocean. (Old advice says you need to change your oil every 3,000 miles, but most auto experts agree that’s a myth—modern gasoline engines can go two or three times that distance between changes.)
You will also need 10 tons of snacks. Hopefully there will be plenty of intergalactic comfort zones, or your trunk will be too full.
It would be a very long journey, and the landscape wouldn’t change much at all. Most of the visible stars will burn out before they leave the Milky Way. If you want to try touching a star at room temperature, I suggest planning a path that takes you beyond Kepler-1606. It’s 2,800 light-years away, so when you pass it after 30 billion years, it will cool to comfortable room temperature. She currently has a planet, although it will likely have devoured it by the time she gets there.
Once the stars burn out, you will have to find a new source of entertainment. Even if you brought every audiobook ever recorded and every episode of every podcast, it wouldn’t even last you to the edge of the solar system.
British anthropologist Robin Dunbar suggested that the average human maintains about 150 social relationships. The total number of humans who have ever lived is somewhere north of 100 billion. A 10-year road trip would be long enough to bring each one of these people back to life in real time — in some sort of unedited documentary — and then rewatch. Each of those documentaries 150 times, each time with a different commentary track by 150 people who know the topic better.
By the time you finish watching this full human perspective documentary, you’ll still be less than 1 percent of the way to the edge of the universe, so you’ll have plenty of time to rewatch the entire project – every human life with all 150 commentary tracks – 100 times before you finally arrive.
Once you reach the edge of the observable universe, you could spend another 4.8 x 10 years driving home, but since there’s no Earth to go back to – only black holes and frozen star crusts will remain – maybe ok keep going.
As far as we know, the edge of the visible universe is not the edge of the actual universe. It’s only the farthest we can see, because there hasn’t been time for light to reach us from any farther parts of space. There is no reason to believe that space itself ends at that particular point, but we don’t know how far it goes. It may last forever. The edge of the visible universe is not the edge of space, just the edge of the map. There is no way to be sure of what you will find when you cross it.
Be sure to pack extra snacks.
Adapted from “What If? 2: Additional Serious Scientific Answers to Absurd Hypothetical Questions,” published by Riverhead Books, a member of Penguin Random House LLC.
