# Why does mass increase the closer you get to light speed? **URL:** \ **Category:** Factual Questions\ **Created:** [August 8, 2003, 9:42pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918 "2003-08-08T21:42:09Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [August 9, 2003, 1:49pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/21 "2003-08-09T13:49:28Z")
In one sense the mass does _not_ increase as you accelerate. If you have two objects orbiting each other around their common center of gravity, their gravitational pull on each other doesn’t change regardless of how fast they’re moving relative to you. Technically, what’s increasing is the objects’ momentum, and it’s not a property of the objects themselves but of the difference between your reference frames. In a sense it’s spacetime itself that’s soaking up the extra energy. ---
**Author:** ![wolf\_meister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolf_meister/32/15202_2.png) [@wolf\_meister](https://boards.straightdope.com/u/wolf_meister)\ **Post date:** [August 9, 2003, 4:23pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/22 "2003-08-09T16:23:25Z")
**friedo** Sorry, what I did was to refer to a situation that was brought up in another thread about speed of light travel. Still, I think the power (or thrust) source is the real problem. ---
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [August 9, 2003, 4:45pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/23 "2003-08-09T16:45:11Z")
> [@](#): > > \*Originally posted by wolf\_meister \* > \*\* > Still, I think the power (or thrust) source is the real problem. \*\* Well, yes, but only in the sense that it would take an infinite amount of energy to boost something with mass to a speed even approaching an appreciable fraction of the speed of light. Its fairly easy to get something to accelerate at a greater rate than the Earth’s gravity - how do you think anything is ever launched into space? ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [August 9, 2003, 5:26pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/24 "2003-08-09T17:26:33Z")
Depends what you mean by an appreciable fraction; if you only want 0.2 c, relativistic effects are not very great; it takes a massive amount of energy required to get to that speed, but not infinite. Especially if the payload is small. ---
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [August 9, 2003, 5:33pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/25 "2003-08-09T17:33:20Z")
> [@](#): > > \*Originally posted by Angua \* > \*\*Well, yes, but only in the sense that it would take an infinite amount of energy to boost something with mass to a speed even approaching an appreciable fraction of the speed of light. Its fairly easy to get something to accelerate at a greater rate than the Earth’s gravity - how do you think anything is ever launched into space? \*\* Your an astronomer, you should know better than that! It takes a finite amount of energy to boost something with mass to any appreciable fraction of c less than 1 and for a subatomic particle with mass that amount of energy’s not that huge. IIRC solar sails could feasibly reach speeds of 0.5c. Anyway, back to the orginal question, something with a relative velocity, v, travelling along the x axis of a an observer has the relative mass: m[sub]v[/sub] = m[sub]0[/sub]/(1 - v[sup]2[/sup]/c[sup]2[/sup])[sup]1/2[/sup] taking the liming case of v=c, you end up with: m[sub]v[/sub] = m[sub]0[/sub]/0 which basically means that travelling at the speed of ligth for anything with mass is impossible. ---
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [August 9, 2003, 7:40pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/26 "2003-08-09T19:40:37Z")
> [@](#): > > \*Originally posted by MC Master of Ceremonies \* > \*\*Your an astronomer, you should know better than that! > > It takes a finite amount of energy to boost something with mass to any appreciable fraction of c less than 1 and for a subatomic particle with mass that amount of energy’s not that huge. IIRC solar sails could feasibly reach speeds of 0.5c. > \*\* Sorry. That’s what I was trying to say. But say, trying to get a rocket to an appreciable fraction of c is very difficult. You’re right, I should know better, I deal with galaxies which have relativistic plasma jets travelling at at least 0.5c. :smack: ---
**Author:** ![Janus20](https://avatars.discourse-cdn.com/v4/letter/j/91b2a8/32.png) [@Janus20](https://boards.straightdope.com/u/Janus20)\ **Post date:** [August 14, 2003, 6:43am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/27 "2003-08-14T06:43:17Z")
It only increases if you believe in Einsteins elastic time concept and when physicists apply this theory it delivers answers which are described as ‘infinite singularities’. Infinite singularities are a mathematical euphemism for ‘absurdities’. The layman would ask ‘Why not stupidities?’. Physics spin doctors argue that ’ It is far, far better to die stupid than to stop the money that helps us die stupid in relative comfort’. This makes more sense than Einstein ever made and they do not have to attend to more stupities called the Thermodynamic Laws. Mass not time is relative and proof is at [www.thewebspert.com/cresswell/](http://www.thewebspert.com/cresswell/) but you will not find help on this or any other Forum. Until all physicists and other charlatans are pitched out into a lonely street with an empty rice bowl; you must grin and bear it. Janus20 ---
**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\ **Post date:** [August 14, 2003, 7:07am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/28 "2003-08-14T07:07:25Z")
Dude, we don’t even get rice? At least when mainstream physicists depose our nemeses, we give them a pack of crackers… Maybe a candy bar… I think it’s pretty easy to distinguish the good side from the evil side here. ---
**Author:** ![Janus20](https://avatars.discourse-cdn.com/v4/letter/j/91b2a8/32.png) [@Janus20](https://boards.straightdope.com/u/Janus20)\ **Post date:** [August 14, 2003, 7:31am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/29 "2003-08-14T07:31:56Z")
> [@](#): > > \*Originally posted by Achernar \* > \*\*Dude, we don’t even get rice? > > At least when mainstream physicists depose our nemeses, we give them a pack of crackers… Maybe a candy bar… > > I think it’s pretty easy to distinguish the good side from the evil side here. \*\* I have just been to your website and it is clear that in addition to the rice you say you ‘don’t got’, you clearly don’t got much else as well. At the age of 22 you publish **RESEARCH WORK YOU HAVE DONE**? Tell me about good, evil, Einstein and the thermodynamic laws. Give full reign to your intellectual powers. Impress me. Impress others. Impress yourself. Tell me at what age did you recite your 7 times table. ---
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [August 14, 2003, 7:47am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/30 "2003-08-14T07:47:51Z")
> [@](#): > > \*Originally posted by Janus20 \* > [B > > Mass not time is relative and proof is at [www.thewebspert.com/cresswell/](http://www.thewebspert.com/cresswell/) > Janus20 \*\* And has this proof been published in a _respected_ peer review journal? BTW - just a note from a “charlatan” who’s spent an awful lot of time being a charlatan, time is the relative concept, not mass, and that _can_ be proved. **Achernar** , I agree. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [August 14, 2003, 9:23am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/31 "2003-08-14T09:23:47Z")
> [@](#): > > \*Originally posted by Janus20 \* > **Mass not time is relative and proof is at [www.thewebspert.com/cresswell/](http://www.thewebspert.com/cresswell/) but you will not find help on this or any other Forum. Until all physicists and other charlatans are pitched out into a lonely street with an empty rice bowl; you must grin and bear it.** In order to challenge a particular theory, you must show that the predictions from the theory contradicts observed facts. If you want to claim that another theory is better, you must show that it makes correct predictions where the old theory does not. Your link does not seem to show any such examples. The only thing that comes close is “relativity makes unreasonable predictions such as singularities,” but it does not explain why singularities are “unreasonable.” Your ad hominem attack on **Achernar** will not get you anywhere either. ---
**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\ **Post date:** [August 14, 2003, 9:56am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/32 "2003-08-14T09:56:57Z")
That was an attack? I didn’t want to say anything because I really couldn’t tell. ---
**Author:** ![Ms2001](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ms2001/32/18463_2.png) [@Ms2001](https://boards.straightdope.com/u/Ms2001)\ **Post date:** [August 14, 2003, 10:32am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/33 "2003-08-14T10:32:38Z")
> [@](#): > > \*Originally posted by Janus20 \* > **It only increases if you believe in Einsteins elastic time concept and when physicists apply this theory it delivers answers which are described as ‘infinite singularities’. Infinite singularities are a mathematical euphemism for ‘absurdities’. The layman would ask ‘Why not stupidities?’.** Of course time is relative. Don’t you know there are [4 different simultaneous 24 hour days within a single rotation of Earth? Greenwich 1 day is a lie.](http://www.timecube.com) 🙂 ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [August 14, 2003, 10:34am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/34 "2003-08-14T10:34:40Z")
Hmm, maybe it wasn’t meant as an attack, my apologies to **Janus20** if I misunderstood. ---
**Author:** ![Angua](https://avatars.discourse-cdn.com/v4/letter/a/8baadc/32.png) [@Angua](https://boards.straightdope.com/u/Angua)\ **Post date:** [August 14, 2003, 10:35am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/35 "2003-08-14T10:35:58Z")
I don’t think you did misunderstand. ---
**Author:** ![Janus20](https://avatars.discourse-cdn.com/v4/letter/j/91b2a8/32.png) [@Janus20](https://boards.straightdope.com/u/Janus20)\ **Post date:** [August 14, 2003, 11:57am UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/36 "2003-08-14T11:57:39Z")
> [@](#): > > \*Originally posted by Angua \* > \*\*And has this proof been published in a _respected_ peer review journal? > > BTW - just a note from a “charlatan” who’s spent an awful lot of time being a charlatan, time is the relative concept, not mass, and that _can_ be proved. > > **Achernar** , I agree. \*\* ‘Respected journal’ of a mutually masturbating self appreciation Cult. Just how naff and naive can you get. I have a picture of half a million ‘peers’ queing up for their euthanasia pop. I would rather appeal to a cuckoo to stop its egg laying habits at the expense of other bird species. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [August 14, 2003, 12:37pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/37 "2003-08-14T12:37:22Z")
I don’t know if this is worth debating, but anyway… I think people like **Janus20** have never talked with a real scientist. Scientists are genuinely interested in truth and not concerned with protecting some mysterious set of sacred text. To a scientist, nothing is more exciting than the prospect of _dis_proving the accepted theories because that would bring us closer to the truth (and bring fame and fortune to the discoverer - well, at least fame). Unfortunately there are some cases of peer review which rejected papers that challenged the reviewer’s pet theory, but that’s very rare. If a new theory agrees with all known observed facts and makes some interesting predictions, then I don’t think any reviewer can reject it with good conscience. Same with observations that seem to contradict the currently accepted theories. I’ve met respected scientists who said they spent all their lives trying to disprove the theory of relativity and failed. And threre’s nothing wrong with that - that’s what scientists are supposed to do. ---
**Author:** ![Janus20](https://avatars.discourse-cdn.com/v4/letter/j/91b2a8/32.png) [@Janus20](https://boards.straightdope.com/u/Janus20)\ **Post date:** [August 14, 2003, 2:51pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/38 "2003-08-14T14:51:38Z")
> [@](#): > > \*Originally posted by scr4 \* > \*\*I don’t know if this is worth debating, but anyway… > > I think people like **Janus20** have never talked with a real scientist. Scientists are genuinely interested in truth and not concerned with protecting some mysterious set of sacred text. To a scientist, nothing is more exciting than the prospect of _dis_proving the accepted theories because that would bring us closer to the truth (and bring fame and fortune to the discoverer - well, at least fame). Unfortunately there are some cases of peer review which rejected papers that challenged the reviewer’s pet theory, but that’s very rare. If a new theory agrees with all known observed facts and makes some interesting predictions, then I don’t think any reviewer can reject it with good conscience. Same with observations that seem to contradict the currently accepted theories. I’ve met respected scientists who said they spent all their lives trying to disprove the theory of relativity and failed. And threre’s nothing wrong with that - that’s what scientists are supposed to do. \*\* It must be ten years since Stephen Hawking predicted a Unified theory in about 30 years time. He also said that it would mean ‘the end of physics’. Diagram 2 totally destroys the thermodynamic laws. Hawking has known about this March 1989 and one of his sychophants promised me a reply but I must understand how very busy he was and it would take some time. Since then Hawking has been touring the world as an electronic voice cabbage. He has become Norman Bates’ mother. It is obscene that the Cambridge U Newtonian chair uses him in such a disgraceful fashion. A Unified theory means the end of physics government funding for the universities. Who is ‘us’ that is seeking the exciting truth. ‘Us’ do not want the truth. They want an infinite supply of money to keep the search going. Grow up. If ‘us’ were to float on the stock market it would not attract a single dud penny. In less than two years physics and astronomy will be removed from all dictionaries in the world. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [August 14, 2003, 3:32pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/39 "2003-08-14T15:32:11Z")
> [@](#): > > \*Originally posted by Janus20 \* > **Diagram 2 totally destroys the thermodynamic laws.** This claim is refuted in [this thread](http://boards.straightdope.com/sdmb/showthread.php?threadid=203580). > [@](#): > > \*\* Stephen Hawking predicted a Unified theory in about 30 years time. He also said that it would mean ‘the end of physics’… A Unified theory means the end of physics government funding for the universities. They want an infinite supply of money to keep the search going.\*\* This is completely ridiculous. First of all, it’s bleeping ovious that when two laws contradict with each other (quantum mechanics and relativity), there must be law that unifies both. That doesn’t mean we have any clue as to what that law is. And do you seriously think scientists have some pact to make sure we never reach the holy grail? It’s like mountain climbers saying “let’s agree never to reach the top of Mt. Everest, that way we can all continue to get funded to keep trying.” Nobody is going to agree to that, because the potential benefits from being first on the top is far, far greater. Whoever discovers the Grand Unified Theory (GUT) can live like a king for the rest of his/her life just by giving public lectures. Besides, the GUT is not the end of physics. It may be the end of the quest for understanding the fundamental laws of physics, but that’s only a small part of physics. Applying those laws is far more important. There are scientists who make a living by using nothing more than Newton’s Laws to explain astronomical phenomena (e.g. those working on numerical simulations of galaxies.) I myself work on trying to understand solar flares, and a GUT will not make this quest easier or meaningless. I should also note that applied science is where the money is even now - the supercollider never got built while fusion research and environmental science seem to be well funded. You see, even if you know the fundamental laws, it doesn’t mean it allows us to predict the behaviour of any system we want. You’d think quantum mechanics would allow us to calculate the emission spectrum of any type of ion. But the calculations involved is so complex that we still rely on measurements instead. The GUT will not solve this problem because all it does is apply a negligibly small correction to the equations. (Negligible for this particular problem, that is.) ---
**Author:** ![KidCharlemagne](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@KidCharlemagne](https://boards.straightdope.com/u/KidCharlemagne)\ **Post date:** [August 14, 2003, 4:28pm UTC](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918/40 "2003-08-14T16:28:42Z")
**Janus20** , Stop being a dick. [Previous page](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918.md?page=1) [Next page](https://boards.straightdope.com/t/why-does-mass-increase-the-closer-you-get-to-light-speed/193918.md?page=3)