3306: Accelerator Energies

Accelerator Energies

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Title text: Fans at Daytona always get extra excited when officials decide to introduce some antimatter cars circling the track in the opposite direction.

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Explanation

This is one of 53 incomplete explanations: This page was created by JEFF GORDON COLLIDING WITH A RELATIVISTIC PROTON. We should explain why Daytona and particle accelerators aren't comparable like this, and overview at least a few of these accelerators. Don't remove this notice too soon. You can help by editing the explanation!

This comic demonstrates a relatively linear relationship between the length of various particle accelerators and the collision energy they are capable of producing. It then adds an outlier data point for the Daytona International Speedway, a track for car races, which suggests it is much more efficient for its size than the accelerators. This is not a particularly meaningful comparison, since the two are completely different things.^{[citation needed]} Utilizing the collision energy related to the Daytona Speedway, i.e. aligning cars for controlled collision in a detector section, may give rise to ethical concerns, in case human drivers are involved.

eV stands for electronvolt, a non-SI unit of energy. It is typically used in particle physics, where exceedingly small and light particles are accelerated to exceedingly high velocities approaching the speed of light, thus boosting their energy; it is also sometimes used as a unit of mass through E = mc², such as in 2186: Dark Matter and 2035: Dark Matter Candidates. Trying to increase the energy as much as possible to create collisions that allow us to probe ever deeper in subatomic physics leads to ever-larger machines, some having circumferences of dozens of kilometers, necessary because particles' energy losses are smaller with larger, gentler curves. This also makes accelerators far more expensive.

Judging by collision energy alone, a race car is a far more space-efficient way to cause a collision than a particle accelerator. At first glance, it may seem remarkable that a simple raceway produces collisions with energies so much higher than those of the various particle colliders, by about 10 orders of magnitude. It is important to note that the comparison needs to take into account the masses of the colliding objects. A vehicle might have a mass of 1000 kg or more, with a current Next Gen vehicle specified for a minimum operational mass of 1542 kg with driver and fuel. The Large Hadron Collider operates on particles ranging from protons (1 atomic mass unit, 1.66 x 10^-27 kg) to lead atom nuclei (204 to 208 AMUs, 3.388 x 10^-25 to 3.45 x 10^-25 kg). Race cars are thus more than 10²⁷ times as massive as the particles accelerated by the LHC, and therefore have higher collision energies despite their much, much slower speeds. Particle colliders do, however, provide much higher energy-divided-by-mass values. Racetracks can be shorter than the largest accelerators but, beyond a certain point, this isn't hugely relevant to the collision speed, which has more to do with the capabilities of the cars.

Some particle accelerators have been designed for collisions between matter and antimatter, such as between electrons and positrons or protons and antiprotons, in which all matter is typically destroyed and converted into energy (at least in theory; with baryons, it is often the case that only some of the quarks/antiquarks annihilate). Introducing antimatter circling in the opposite direction allows more energy to be put into the collision products because the original particles are destroyed, so the equivalent energy of their rest mass—and, more significantly, their remaining kinetic energy after the collision—does not detract from the energy budget available to create collision products. This does not matter as much as people think it does, but it could lead to audience excitement because of pure energy (light) that would be emitted.

Introducing a hypothetical antimatter race car would not only result in even more carnage but in a huge explosion as well. The Hiroshima atomic blast released energy equivalent to less than a gram of matter, so a matter-antimatter annihilation of 1000 kg race cars would be more than a million times larger — more than sufficient to excite the particles of all spectators present to the point of their complete destruction. Since the track and the air above the track are both made of matter, said annihilation would start immediately; sending the antimatter cars around the track to collide into matter cars would require finding some way to delay matter/antimatter reactions.

Randall has compared a race track with a particle accelerator before.

Transcript

This is one of 35 incomplete transcripts: There's a rough graph of the energies here. Don't remove this notice too soon. You can help by editing the transcript!

[A scatter-plot graph. The Y axis is labeled "Collision Energy" and shows values from 1 eV to 10²⁷ eV, marked at every 3rd order of magnitude, using SI prefixes up to 1 PeV, then switching to scientific notation from 10¹⁸ eV; the SI prefixes Eta, Zetta, Yotta and Ronna are not used for higher values. The X axis is labeled "Track Length" and shows values from 10 cm to 100 km, marked at every order of magnitude. Three of the datapoints lowest to the left on the graph are each labeled as "First Cyclotrons" and are numbered #1, #2, and #3 below. Based on manual fitting, the datapoints in the scatter plot are as follows, with the location and the label applied:]

[Length of 0.28 metres, energy of 3.00E+04 electronvolts:] First Cyclotrons [first of three points pointed at by this label]

[Length of 2.9 metres, energy of 3.00E+06 electronvolts:] First Cyclotrons [second of three points]

[Length of 5.7 metres, energy of 9.50E+06 electronvolts:] First Cyclotrons [third of three points]

[Length of 4.8 metres, energy of 2.80E+08 electronvolts:] ADA

[Length of 54 metres, energy of 2.10E+09 electronvolts:] COSMOTRON

[Length of 101 metres, energy of 1.10E+10 electronvolts:] BEVATRON

[Length of 250 metres, energy of 3.50E+09 electronvolts:] BEPC-II

[Length of 1460 metres, energy of 3.00E+10 electronvolts:] J-PARC

[Length of 2500 metres, energy of 8.00E+09 electronvolts:] CEBAF

[Length of 4300 metres, energy of 6.00E+10 electronvolts:] RHIC

[Length of 4800 metres, energy of 4.70E+24 electronvolts:] Daytona Speedway

[Length of 6200 metres, energy of 8.00E+11 electronvolts:] TEVATRON

[Length of 17500 metres, energy of 1.20E+13 electronvolts:] Large Hadron Collider

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Discussion

I asked Gemini and the data point actually makes sense: A 1000 kg car driving at 60 km/h has approximately 8.67 x 10^{23}{ eV} (or about 867 sextillion electron volts) of kinetic energy. Andy311 (talk) 00:42, 3 October 2026 (UTC)Andy03

Did you really need Gemini to calculate ½mv² for you? Wolfram Alpha could probably have given you that answer without burning the rainforest... as much. 2A02:6EA0:C803:6245:0:0:0:32 03:50, 3 October 2026 (UTC)

Even better question would be "did you really need to mention what you used?". Imo that's an ad bot and that comment should be removed 159.224.64.162 09:35, 3 October 2026 (UTC)

I agree, and also it's a bad answer for scientific reasons. The assumptions (1000 KG & 60 KM/H) are bad - the cars used in that racetrack weigh at min 3200 lb empty & 3400 lb with driver + fuel; 3300 lb (~1500 kg) is a better estimate; similarly, track averages for an entire race are vastly higher, and during an entire race, average speeds appear to be ~230-240 KM/H for recent Daytona 500's (single lap records are significantly higher, but from context it seems Randall is looking for an average race) - 60 km/h is so far off that it's a common minimum speed limit on US interstates. And lastly, the estimates in the original post have only one significant figure, so the output can't have more.

Wolfram Alpha says the kinetic energy of 3000 kg @ 465 KM/h (double both single car estimates, because two cars in opposite directions) is 25 MJ, aka ~1.6x10^26 eV. As a bonus, since other people can see my work and reasoning, they can easily spot where (if anywhere) I messed up. 9x10^23 is more than two orders of magnitude off from my answer, and also clearly not Randall's, because I think we can all agree the track is placed above 10^24.

I wouldn't entirely commit to it being spam - but I think "I asked a LLM how to think" is antithetical to XKCD & all wikis everywhere, and so I think it should be removed either way. 2603:8002:AE00:2F2D:79A6:33F0:A067:813 18:38, 4 October 2026 (UTC)

You can't "double both single car estimates" (you can, but it is wrong). This would magically increase the energy by a factor of 8 (instead of 2). Hitting an opposing car of same mass and speed is effectively like hitting an indestructible/inflexible wall. --134.102.219.31 14:24, 5 October 2026 (UTC)

It's still really impressive that the LHC can accelerate fundamental particles weighing less than a trillionth of a trillionth of a kilogram to even a trillionth of the kinetic energy of a race car. That means a single bunch of 100 billion protons (with total rest mass 10^-16 kg) accelerated by the LHC will have energy comparable to a race car. 174.160.19.108 07:48, 3 October 2026 (UTC)

We should get two remote controlled stock cars going in opposite directions and different lines going around Daytona. Once they reach top speed (which takes a few laps, thanks to restrictor plates), crash them headlong into each other and see what's left--2600:6C50:D00:6:8D06:71D6:F0A2:C19C 08:26, 3 October 2026 (UTC)

Description for Daytona Speedway. I don't trust myself to actually edit the wiki, but it would be useful to describe what the Daytona Speedway is for people like me who don't know. Also linking the wiki page for it is a good idea. Da0neDatGotAway (talk) 09:07, 3 October 2026 (UTC)

Done Elektrizikekswerk (talk) 12:38, 3 October 2026 (UTC)

Each lap is 2 1/2 miles, or about 4 km. I'm guessing "8 km" in the graph is "4 km for the regular car, 4 km for the antimatter car." 150.221.155.241 23:02, 3 October 2026 (UTC)

@Da0neDatGotAway Wait, why do you not trust yourself to edit our wiki? We want everyone to want to help! Is there something that we can do to make the experience of editing the wiki more enjoyable/less stressful for you?? FaviFake (talk) 19:44, 3 October 2026 (UTC)

I'd like to see more attention to the "excited" pun: the spectators are emotionally excited, and very soon their atoms and subatomic particles will be excited into higher energy states by the influx of energy emitted by the the matter/antimatter collision. 2601:19B:4103:97F0:4C25:69BD:828:E819 12:38, 3 October 2026 (UTC)

Someone needs to add a table listing parameters for each of the accelerators listed on the plot. And the transcript should just list the approximate X/Y values for them. Barmar (talk) 13:25, 3 October 2026 (UTC)

Check the history for the Transcript when it was temporarily a table. You can use that actual table in the Explanation and 'make more approximate and only casually informative' the Transcript, without losing any hard-won original researched information. 92.23.3.72 21:19, 5 October 2026 (UTC)

There are names for the higher orders of magnitude too. In increasing order, starting from 10¹⁸: EeV, ZeV, YeV, ReV (and QeV also exists, but is not on the graph, for it only goes up to 10 ReV). 1 QeV would be close to the upper end of the image. 2001:4C4D:12D3:9400:482:1C16:1CFB:F131 15:26, 3 October 2026 (UTC)

Seems dubious to me - how would you even go about fitting 10^27 EVs into Daytona Speedway? You'd have to stack them ridiculously high. 86.22.132.121 08:29, 5 October 2026 (UTC)
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