# Can I build a space elevator from superman's hair?

In Superman IV: The Quest for Peace (imdb) a single strand of Superman's hair is seen suspending a 1000lbs weight.

Is is possible to build a space elevator from strands of a super strong human-hair-like material?

How long would it take to harvest enough hair from a superbeing like superman to build a space elevator?

http://en.wikipedia.org/wiki/Space_elevator

• Assume that Superman's hair grows at the same rate as an average human.
• Assume that other than strength, the properties of the hair are the same as human hair.
• Assume that the museum got the maximum stable tensile strength of the hair roughly right.
• The space elevator need only be the minimum height for functional use.
• The elevator will be used to lift general payloads into orbit, ship parts, people, fuel etc.
– Jax
Commented May 19, 2015 at 13:36
• It seems like this just turned into a what-if-xkcd question... Commented May 19, 2015 at 21:36
• I wonder how he cuts his hair... Commented May 25, 2015 at 17:56
• @WayneWerner Kryptonite-edged razor? Commented May 26, 2015 at 13:55
• In the short term it'd be easier to recruit Superman to just lift things into space. Really, if Superman wanted to contribute to the world, he'd stop bothering with crime-fighting which we have a reasonable handle on and turn his powers to space programmes Commented Aug 25, 2015 at 10:55

Lets assume that 1000lbs(453.592 KG) is close to the limit of a single strand of his hair.

Lets assume his hair weighs about the same as an average humans hair by length. http://www.answerbag.com/q_view/2159502 "a single strand of hair 4 1/2(11.43 cm) inches in length weighs, on average, 0.62 milligram" Which gives us about 5.42 mg per meter.

A space elevator has to reach beyond geostationary (35,786 kilometres) so lets say 36000km for round numbers.

So at a minimum the hair has to be able to support its own length.

36000km of this hair would weigh 195.1 kg, less than half our limit.

So far so good.

The hair is about twice as strong as the absolute minimum needed but we're not going to be able to put much weight on it, a strong wind or a few people climbing it would breach our limit so we're likely going to need a thick braid to do anything useful.

From a little reading of the wiki the lift capacity for a reasonable space elevator is given as 20 tons so to get this we're going to need a cable at least 100 hairs thick, 200 to be safe.

Here's where we hit a problem.

How long would it take to harvest the needed hair? In a lifetime a human might grow 590(949.5km) miles of hair.

http://www.express.co.uk/news/weird/437344/Average-human-grows-590-miles-of-hair-and-eats-35-tons-of-food-AMAZING-human-stats

Lets assume this is over about 80 years so 11.86875 km per year for a normal human.

This is a lot of hair but not nearly enough for even a single strand in our braid.

If superman used his (so far undocumented) super-hair-growing powers how fast would he have to push out hair material to make a 100 thick braid cable in a reasonable time? Lets give him 20 years of doing nothing but sitting and growing hair as hard as he can.

To build our 100 strand elevator we're going to need 3,600,000 km of hair.

It would take a normal human 303317.5 years to grow enough. To grow enough in 20 years superman is going to need to grow it about 15166 times faster than that. Normal human hair growth is 0.44 mm per day, superman would need to grow his head of hair at 66.73 meters per day, if you talked to him you would see it visibly coiling out of his head.

Though he might just volunteer to spend a few years carrying mountain-sized chunks of equipment into space for us instead.

• @AndrewCoonce The 66.73 meters per day was assuming his whole head of hair growing that fast. I think with it all focused on only 200 hairs coming out at once it might be shooting out like a party popper. Commented May 19, 2015 at 14:44
• The cable can be tapered to improve the efficiency of material use. It gets weaker as it has less to weight below it. Commented May 19, 2015 at 15:46
• I think you could arrange some Rogain to acquire super powers. Objets are often enchanted in this way in such stories as part of the plot. If this will be fan fiction, ask on Fiction SE about what means have been used in canon. Oh, you might also find a way to synthesize it or culture his cells. What you need is a flock of Kryptonian sheep. Commented May 19, 2015 at 15:51
• There's still 1 problem: Cutting the hair .. O.o Commented May 19, 2015 at 19:05
• Perhaps if Superman has ten Superchildren, they each have ten, etc; for four or five generations, it would be faster. Ahh, those good times we used to have together when we sat around a picnic blanket in the local park and grew hair! Commented Jul 9, 2015 at 1:48

Well, it's going to take a while.

We can assume we need about a minimum of 25,000 miles of cable (22,000 miles for geosync orbit, plus 3000 for the counterweight).

The elevator car will weigh about 100,000 lbs. Why? Because it's a round number in the range of the Space Shuttle's empty weight. The payload needs to support 40,000lbs, because that's the range of the first ISS module. So we need to support 140,000lbs of cargo.

For simplicity, let's just say we need 200,000 strands of hair 25,000 miles long, with 10% extra for joining and split ends. So 5.5 million miles of hair, or one 36,000 mile long head of superhair (see below).

Superman is superhuman, so while the average dark haired person has only about 110,000 hairs on his head, he has 150,000. Each hair grows at 0.04cm/day or about 0.016in/day. That's $2.5 \times 10^{-7}$ miles per day. We'll need his whole head for the weight we need to support.

Google says that's 144,000,000,000 days. That's just shy of 400,000,000 years. By that time, humans could be a type III civilization, rendering the whole thing moot.

Just for the sake of an argument, let's say superman's hair is infinitely strong, like the magic alien spear. Now a single strand can support the whole weight of the elevator system.

We still need 36,000 miles, but now the hair grows at 0.037 miles/day! And since hairgrowing is one of his superpowers, he can do it 500× faster than the average human. So now we have 1.86 miles every day! In that case it will take us only 53 years to grow a space elevator. Since superman has been around since the 1930s, we should have enough of his hair laying around to make this work!

• The redhead comment is funny if you know that people with red hair have on average only 90,000 hairs rather than the 140,000 that people with blond hair can have, but for people who don't know that, the redhead comment might sound a bit odd ;) Commented May 19, 2015 at 18:44
• That's exactly it @trichoplax. I guess most people wouldn't necessarily know that bit of trivia. :) Commented May 20, 2015 at 3:20
• The space shuttle had engines, cockpit and aerodynamic surfaces. None of which our car needs. Commented May 20, 2015 at 6:30
• Car Weight: Space Shuttle weighed 165000 lbs empty, excluding all external engines/tanks. I guessed 100,000 lbs for the car, assuming there would be weight for significant failsafe mechanisms, life support, etc; but there may be some fat there. Commented May 20, 2015 at 14:05

Everyone is missing a big problem here: How do you scale from hair to a cable? The hair is strong enough, but how do you bond the hairs together?

We already have fibers that are strong enough to build a space elevator, it's the scaling problem that is the current showstopper.

• Teeny Tiny knots. I added 10% for "joining and split ends". Commented May 20, 2015 at 3:21
• @Josiah And why would they not simply slip given the loads on the cable? Commented May 20, 2015 at 4:22
• Knots are usually weaker than the material they're made from, so that would have to be taken into account. Commented May 20, 2015 at 9:10
• Yes, the knots will lose some strength, but a double fisherman's knot has something like 80% strength according to the cordage institute and in 12,000 lb tests wasn't susceptible to pulling out. I also noted that the 1000lb weight was apparently secured with a knot, so presumably that margin was already included (at least to some extent). Commented May 20, 2015 at 14:19