# Broom Performance and Endurance

• 06-25-2010, 11:36 PM
Tim the Enchanter
Broom Performance and Endurance
Let's just use the Firebolt as our model.

The Firebolt is said to reach 150 miles per hour in ten seconds. Let's just ignore air resistance for the moment and assume this is constant acceleration.

150 miles per hour = 67 metres per second

acceleration = change in velocity / change in time

a = Δv / Δt
a = (67 m/s)/(10 s)

acceleration = 6.7 m/s/s

That's pretty impressive. Almost exactly on par with a Ferrari Enzo going to 100 mph in 6.6 seconds!

Unfortunately, we have no way of knowing the mass of the broomstick pilot when they compiled that figure. So let's just ignore the varying masses of different potential riders and concentrate on the broom.

Anyway, here's the question: What is the Firebolt's top speed in an atmosphere?

I do not think the 150 mph figure is an indication of its top speed, rather it is a measure of its acceleration. Much like how in the Muggle world, in which the performance of cars is expressed in how many seconds it takes for the vehicle to reach 60 mph, wizards seem to express acceleration by switching the two factors - having time as the fixed number, and seeing how fast the broom will go in that period.

We have two canon examples:

Firebolt: 0 to 150 mph in 10 seconds
Cleansweep 11: 0 to 70 mph in 10 seconds

Given that the time factor is the constant, this leads me to believe that both of these broomsticks are capable of going faster than the respective 150 and 70 mph figures.

But how fast?

Without a rider, a broomstick by itself is a relatively aerodynamic object. Let's just say that this Firebolt can fly without a rider. What do you think would be its top speed at sea level? At jet-cruising altitude (around 10,668 metres for many airliners)?

And for that matter, what do you think would be the maximum cruising altitude of a riderless Firebolt? Considering that brooms do not need any kind of fuel or oxygen to operate (as far as we know), could a broom conceivably just fly off into space, if we ignore the human factor?

Now for a rider. A Harry Potter-shaped mass is not very aerodynamic, obviously. What do you imagine to be the top speed of a Firebolt with a rider? Given air resistance, could it even be lower than 150 mph, as stated in the advertisement? Of course, there are probably spells to reduce drag, so how much would this increase performance?

~~~~~~~~~~~

And here's another question. What do you think is the endurance of a Firebolt?

Brooms don't need fuel. Given this fact, we have several options:
1. The broom can fly until it feels 'tired'
2. The broom can fly until the charm that makes it fly wears off
3. The broom can fly forever

What do you think would be the endurance, given options one or two?

And to get a bit science-fictional, let's contemplate what would happen if you stick a broom in the vacuum of space.

First of all, do you think a broom will be able to operate in space? Remember, it doesn't require fuel or air to burn, as it is propelled by magic. But could this magic still work in a vacuum?

And now for the big one:

If the broom can work in the vacuum of space, could it reach the speed of light? Beyond?

For all intents and purposes, the broom is a reactionless drive, meaning it doesn't need to throw stuff out the back in order to go forward. So, freed from fuel constraints, the broom could just keep accelerating until the spell on the broom wears off, which could be a very long time. Now, 6.7 m/s/s is rather slow acceleration when we're talking about interstellar distances, but the broom could feasibly accelerate at this rate for years, if the spells hold up. And if it can accelerate at 6.7 m/s/s constantly, and with no pesky fuel and reaction mass issues to worry about, I believe it is possible for this broom to get to 99.99% of light speed (since Einstein says you can't actually reach it) in less than two years (at 1 g, or 9.81 m/s/s, you can almost reach light speed in just about a year). What do you think?

But what about faster-than-light travel (FTL)? The laws of physics say that FTL travel is impossible, but as we well know, magic laughs in the face of science. Is it possible that this broom, being a reactionless drive (and possibly also having spells to reduce its mass to nil), could travel faster than light? Is magic the solution to the problems of FTL and interstellar travel?

Tim the Enchanter
• 06-26-2010, 12:47 AM
HARRYHARRYHARRYs_twin
First of all, I'm undecided on whether you're mad or brilliant, Tim, or a bizarre mix of the two. I'm leaning toward the latter.

First of all, do you think a broom will be able to operate in space?

With how I concieve the charms on the brooms work, I think not. I always considered brooms to propel themselves by kind of pushing off the air. With the lack of that ability, I think a broom would either be useless or very close to it in space.

And how is the broom entering space? There are charms that prevent burning in fires, but I doubt that would be effective enough to prevent death of the person and destruction of the object attempting to escape Earth's atmosphere. Charms would have to be developed to allow And how fast would the broom need to be moving in order to escape the atmosphere, anyway? Would that velocity be attainable with the Firebolt?

Yeah, I have no coherent ideas with the rest of the questions. . . . I'll think on them, and prehaps come back later.
xxSelina
• 06-26-2010, 12:59 AM
Tim the Enchanter
Quote:

Originally Posted by HARRYHARRYHARRYs_twin
First of all, I'm undecided on whether you're mad or brilliant, Tim, or a bizarre mix of the two. I'm leaning toward the latter.

Thank you Selina, you are too kind!

Quote:

Originally Posted by HARRYHARRYHARRYs_twin
And how is the broom entering space? There are charms that prevent burning in fires, but I doubt that would be effective enough to prevent death of the person and destruction of the object attempting to escape Earth's atmosphere. Charms would have to be developed to allow And how fast would the broom need to be moving in order to escape the atmosphere, anyway? Would that velocity be attainable with the Firebolt?

For now, I am shamelessly ignoring the human element and the problem of getting the broom into space the first place. The scenario I am postulating assumes that the broom is already floating in space, and does not have to worry about a rider.

EDIT: I am also ignoring drag. Yes, though space is a near-perfect vacuum, there are still trace amounts of hydrogen atoms, dust, and other particulates hear and there. But even hitting a speck of dust at something like 90% of lightspeed (.9c) would unleash just about the same energy as a nuclear bomb, which is not good for the structural integrity of the broomstick. For my scenario, I am ignoring this tricky factor.

Quote:

Originally Posted by HARRYHARRYHARRYs_twin
Yeah, I have no coherent ideas with the rest of the questions. . . . I'll think on them, and prehaps come back later.
xxSelina

Thanks for replying, Selina. I look forward to seeing what thoughts you come up with.

Tim the Enchanter
• 06-26-2010, 02:11 AM
AidaLuthien
My initial reaction is to sing a bit of "De-lovely". You've won my heart and I've lost my brain! :D Oh, Tim, you mad genius.

Quote:

Anyway, here's the question: What is the Firebolt's top speed in an atmosphere?
First off, a straight line test wouldn't be of any use to something which has to be extremely manuverable. That being said, something that can go at jet cruising speed would be horrifying for a person riding it... not that it's impossible.

But judging by the numbers offered, I would agree that the top speed has to be over 150 mph. I'm not willing to do math right now to try and figure it out though.

Quote:

What do you think is the endurance of a Firebolt?
Everything breaks. Eventually. So I am going to immediately discount that it can go on forever, because nothing can.

An inanimate object can't feel tired as far as I'm concerned.

I think if you made someone ride a Firebolt constantly, eventually, the wear and tear on the broom would destroy either the charm or the wood itself. Which ought to be among the tests that broom makers subject it to actually.

I'll answer the sci-fi ones later. Maybe. ;)
• 06-30-2010, 07:03 AM
Tim the Enchanter
Quote:

Originally Posted by HARRYHARRYHARRYs_twin
With how I concieve the charms on the brooms work, I think not. I always considered brooms to propel themselves by kind of pushing off the air. With the lack of that ability, I think a broom would either be useless or very close to it in space.

I always thought that brooms were charmed to simply GO, but you present a very interesting theory. Reminds me of the caterpillar drive in The Hunt for Red October movie, in which the titular Soviet submarine uses an electric current to sort of push against the water.

Quote:

Originally Posted by AidaLuthien
An inanimate object can't feel tired as far as I'm concerned.

But the Weasley's enchanted Ford Anglia did express some recognisable emotions like fatigue and even anger. After all, Harry and Ron did crash because the car felt 'tired', even to the point of waving its windscreen wipers in protest.

Tim the Enchanter
• 06-30-2010, 06:12 PM
msk8
Interesting.

Okay.

What is the Firebolt's top speed in an atmosphere? I would imagine it to be about 200, 250 miles per hour, but that's just going straight. In, say, a game of quidditch, I would imagine that it would probably get to about 100, 125 miles per hour for chasers and beaters because they have to maneover with lots of sharp turns and the like, and it would be bad to have them getting injured because the broom turned too sharply. I'd imagine that for seekers, like Harry, the brooms probably do get to their top velocity when seekers chase the snitch. I think that Keepers would probably also get to a high velocity because they have to have amazing reaction time and all that to be able to get to the correct hoop and block the quaffle before it goes in.

What do you think is the endurance of a Firebolt? I imagine that, like the Weasleys' car, it would get tired. It could probably not keep going forever; there would probably otherwise be some really ancient brooms that are like 800 years old and still work like new. Also, the school brooms are said to be really bad. That could be because they are old, and the technology for them was poor, so they have always been this bad; It could also be because the brooms, like other things, get worn-out as they age and don't work as well. If we say the latter, it could be because the charm wears off or because the broom loses the "will" to keep going. I would say that it loses the "will" because otherwise the charm could probably be renewed. I suspect that the will of the broom decays much faster when it is in use than when it is not. I would say that it does not decay when not in use, but then we might still have 800-year old brooms flying around.

Do you think a broom will be able to operate in space?
No. I imagine that the broom somehow does run on air. The Knight Bus is incapable of running underwater, which leads me to believe that it somehow uses air to transport itself. I suspect that it is much the same with broomsticks. I, like Selina, think that the broomstick somehow pushes off the air(off each molecule, maybe?) or uses the energy in the molecules of the air. I would say that it used the energy in atoms, but that would involve splitting them and causing nuclear radiation, which doesn't seem to fit. Because wizards seem woefully ignorant of science(apart from astronomy)(Judging by Molly Weasley's reaction to Arthur's expirementation with Muggle remedies), especially science on a microscopic and sub-microscopic level, (they have no microscopes or anything like that(Because wizards have telescopes, I would assume that they would need microscopes)) I would suggest that they don't really know how the broomstick propelsion charms work, only that they do work.

If the broom can work in the vacuum of space, could it reach the speed of light? Beyond?
Hmm. I know I just went into a long explanation of how they wouldn't work, but I'm going to answer this anyway. I think not for both questions. I imagine that the broomstick would get much too tired to be able to reach light speed. If it somehow could, I think I heard somewhere that if mass can be speeded up to the speed of light, it turns into light. I think that the broomstick would either turn into light at this point, or be completely destroyed. (Destroyed because the charms placed upon it might prevent it from becoming light.) (by destroyed I mean its mass would just vanish, even if that means disregarding the law for the conservation of mass. Poof.)Oooh, there's also the idea that when it reaches the speed of light and is destroyed/vanishes, it reappears in some other dimension/universe. (I'm just going with that idea; I've got no actual scientific theories or anything to back it up) I do not think the broomstick would, under any circumstances, ever be able to go beyond the speed of light or sustain the speed of light. If the broomstick somehow got to the speed of light, I think it would have to vanish/transport elsewhere, turn into light, or slow down immediately.(The third option would probably not be possible, because reaching the speed of light would probably trigger the vanishing/transformation, making it inevitable once it reached the right speed. I suspect, though, that the vanishing/transformation would be instantaneous.) In the event that the broomstick could make it to past the speed of light without vanishing/transforming, I think it would be much too tired to hold the speed for longer than about ten seconds. (but that's just speculation, no backup, nothing, because physics says it's impossible anyway) I think that with the idea I mentioned before, that broomsticks get "tired" just from being in use, past speeds of about 5000 miles per hour, the speed by which it tired out would grow exponentially.

Hope that helped, even if it was a bit disorganized and ramble-y.

Megan:D
• 06-30-2010, 09:12 PM
Rosi Zeller
I have to agree with Megan; as much as I would love the thought of a broomstick travelling faster than light (If your twin brother went to Sirius (that is, the star) and back at twice the speed of light, how long would he use? And how much younger than you would he be when he got back?), I just can't get over the fact that the broom is made of wood and ... well, mass. Mass can't move faster than light.

I don't agree with Megan, however, on the fact that the broom uses the energy in the molecules in the air. Please tell me if I'm wrong (I have been studying chemistry for three years, but hey, it's summer), but this would mean one of two things: Either the atoms rearrange and form new molecules (which I find highly unlikely) or you lower the air temperature (which would explain why the weather always seem to be rotten at Quidditch matches, but I thought that was just the famous Scottish weather).

Keep in mind, however, that faster-than-light travel is achievable by magic. After all, you've always got Apparition, or Floo powder. I think the difference is that when you use these techniques, you don't travel through
• 07-10-2010, 06:26 PM
Tim the Enchanter
Quote:

Originally Posted by Rosi Zeller
I have to agree with Megan; as much as I would love the thought of a broomstick travelling faster than light (If your twin brother went to Sirius (that is, the star) and back at twice the speed of light, how long would he use? And how much younger than you would he be when he got back?), I just can't get over the fact that the broom is made of wood and ... well, mass. Mass can't move faster than light.

True, but could there be spells that eliminate mass? If so, could a magically mass-less broom feasibly reach c given constant acceleration.

Quote:

Keep in mind, however, that faster-than-light travel is achievable by magic. After all, you've always got Apparition, or Floo powder. I think the difference is that when you use these techniques, you don't travel through
Well, we don't know if these methods are FTL. If they were, Apparation and Portkeys would take you to your destination instantaneously. Unfortunately, they do take a few seconds at least each, which could imply that the time increases with distance. Of course, this would be a problem for interstellar travel.

The other possibility is that Apparation and Portkeys always take a constant amount of time (lets say two or three seconds) to travel to a destination regardless of distance, since I doubt either methods actually transport you across physical space (if they did, people would be crashing through walls whenever they Apparate from indoors). If this is the case, then FTL could be magically feasible. Unfortunately, safely Apparating or creating a Portkey for a destination a few light years away would be a problem.

Tim the Enchanter