The edge of the observatory space is about 270,000,000,000,000,000,000,000 miles away.
If you’re traveling at a steady 65 miles per hour, it will take you 480,000,000,000,000,000 — that’s 4.8 × 10¹⁷ — years to get there, or 35 million times the current age of the universe.
It will be a dangerous trip. I don’t mean because of the space stuff – we don’t worry about all that – but because driving itself is dangerous enough. In the United States, the average middle-aged driver has about one fatal accident per 100 million miles driven. If someone built a highway outside the solar system, most drivers wouldn’t make it past the asteroid belt. Truck drivers who are used to driving long distances on highways have a lower number of accidents per mile than other drivers, but they still probably wouldn’t make it to Jupiter.
Based on national accident rates, the odds of a driver going 46 billion light years without an accident would be about 1 in 10¹⁰^¹⁵. That’s about the same as the probability of a monkey with a typewriter transcribing the entire Library of Congress, without typos, 50 times in a row. You’ll want a self-driving car, or at least one with one of those alarms that alert you if you drift out of your lane.
The trip would use a lot of fuel. At 33 miles per gallon, it would take a glob of gasoline the size of the moon to reach the edge of space. (As of 2021, NASA’s New Horizons spacecraft has traveled about five billion miles on a budget of about $850 million, which works out to 17 cents a mile — pretty much the same as the cost of gas and snacks on a road trip.) You would go through about 30 quintillion oil changes, which would require a container of motor oil the size of the Arctic Ocean. (Old advice says to change the oil every 3,000 miles, but most auto experts agree that’s a myth—modern gasoline engines can comfortably travel two or three times that distance between changes.
You would also need 10¹⁷ tons of snacks. Hopefully there are plenty of intergalactic rest stops or your suitcase will be pretty full.
It will be a very long journey and the scenery will not change at all. Most visible stars burn out before you even leave the Milky Way galaxy. If you want to try to touch a room temperature star, I suggest planning a route that takes you around Kepler-1606. It is 2,800 light years away, so when you pass by it after 30 billion years, it will have cooled down to a comfortable room temperature. It currently has a planet, though it will likely be absorbed before you get there.
Once the stars burn out, you’ll have to find a new source of entertainment. Even if you bring every recorded audiobook and every episode of every podcast, it won’t last you to the edge of the solar system.
British anthropologist Robin Dunbar famously suggested that the average person maintains about 150 social relationships. The total number of people who have ever lived is somewhere north of 100 billion. A 10¹⁷-year trip would be long enough to replay the lives of each of these people in real time—in a sort of unedited documentary—and then watch again each of these papers 150 times, each time with a different commentary from 150 people who knew the subject best.
By the time you’d finish watching this complete documentary on the human perspective, you’d still be less than 1 percent of the way to the edge of the universe, so you’d have plenty of time to rewatch the entire project—every human life. with all 150 comments – 100 times before you finally arrived.
Once you reach the edge of the observable universe, you can spend another 4.8 × 10¹⁷ years traveling back home, but since there will be no Earth to return to—only black holes and the frozen shells of stars—you can just keep going.
As far as we know, the edge of the observable universe is not the edge of the real universe. It is only the farthest we are able to see because there has not been time for light to reach us from the more distant parts of the universe. There is no reason to think that space itself ends at this particular point, but we don’t know how far it goes. It can just go on forever. The edge of the observable universe is not the edge of the universe, just the edge of the map. There is no way to be sure what you will find when you cross it.
Don’t forget to pack extra snacks.
Adapted from What If? 2: More Serious Science Answers to Absurd Hypothetical Questions,” published by Riverhead Books, a member of Penguin Random House LLC.