I just realized we won't be able to go at the speed of light.

[dt890]

Has anyone in this thread touched on the problem of microscopic particles becoming a deadly hazard at near to light speed? Due to collisions?

I bring this up because I have recently read 'The songs of distant Earth' by Arthur C Clarke, and in this story, the spacecraft cannot exceed light speed, but instead can only get close to it, putting it at risk of destruction should it be impacted even by a piece of dust at such enormous speeds.

It gets around the space dust problem by carrying a shield of regular ice a few kilometres thick in front of it, water being a cheap and common material.

Thoughts?

they allready have that problem on the ISS space station. microscopic debris is hitting the station at near light speeds, causing holes and damaged circuitry.

[RedDwarfIV]

they allready have that problem on the ISS space station. microscopic debris is hitting the station at near light speeds, causing holes and damaged circuitry.

Your sure they aren\'t just going at the reverse orbital velocity of the ISS?

[Kryten]

Considering the \'damaged circuitry\' bit, I think he might be thinking about solar wind particles.

[LukeTim]

they allready have that problem on the ISS space station. microscopic debris is hitting the station at near light speeds, causing holes and damaged circuitry.

Are you sure that this is at near light speed?

Seems to me like it\'s more likely to be orbital velocities... so tens of thousands of km/H.

[closette]

Changing your velocity by one unit requires the same amount of energy regardless of how fast anybody else thinks you\'re going.

I know what you mean, but more careful phrasing is needed. For instance it takes me more energy to change an object\'s speed from 10 to 11 m/s than it does from 1 to 2 m/s, since even in the Newtonian regime, kinetic energy = ¹₂ mv².

(E.g. for a m=2kg mass, the first case requires 121 - 100 = 21 Joules and the second requires 4-1 = 3 Joules).

Perhaps a better expression would be 'For you to change your velocity...', since it specifies your instantaneous rest frame as being the one where the energy is measured.

[RedDwarfIV]

Would that be in a vacuum?

[ping111]

SCREW READING, AQUIRE ANECDOTE!

Sorry, I TL;DR\'d this, but only because I don\'t understand piss. Sorry for being born in 2000! =P

Now, when I was little (I know that\'s not a very long time ago) I had just learned the meaning of e=mc2, so I thought that if we travelled at C squared, all matter involved would be reduced to pure energy. Who knows? One of you nerds geniuses will be able to set me straight here...

[LukeTim]

SCREW READING, AQUIRE ANECDOTE!

Sorry, I TL;DR\'d this, but only because I don\'t understand piss. Sorry for being born in 2000! =P

Now, when I was little (I know that\'s not a very long time ago) I had just learned the meaning of e=mc2, so I thought that if we travelled at C squared, all matter involved would be reduced to pure energy. Who knows? One of you nerds geniuses will be able to set me straight here...

I\'m not sure that\'s how it works.

I always thought that the speed of light was just the conversion rate of matter to energy because energy (in the form of photons), of course, travels at the speed of light. So, if you convert a quantity of matter to energy, then it will be converted to photons and as such a number of photons equivalent to the number of particles in the matter originally, traveling at the speed of light, will be produced.

I\'m probably wrong... or something... After CaptainArbitrary\'s post I don\'t know what I know anymore.

[CaptainArbitrary]

I know what you mean, but more careful phrasing is needed. For instance it takes me more energy to change an object\'s speed from 10 to 11 m/s than it does from 1 to 2 m/s, since even in the Newtonian regime, kinetic energy = ¹₂ mv².

It\'s neat you should use that example in a forum about a rocketship game, because the proof of your error is illustrated nowhere better than by the Tsiolkovsky rocket equation: delta vee goes by the logarithm of the mass ratio. Note that: Delta vee. Vee itself —velocity —shows up nowhere in the equation. For a rocketship of a given mass and effective exhaust velocity, it takes precisely the same amount of propellant to change its speed by a certain amount regardless of how fast any particular distant observer thinks the rocketship is moving. It takes, in other words, the same energy.

We have to be real careful not to mix up invariant quantities and coordinate-dependent quantities. Things get all confusing when we do that, and the equations stop giving us useful answers.

[Ted]

SCREW READING, AQUIRE ANECDOTE!

Sorry, I TL;DR\'d this, but only because I don\'t understand piss. Sorry for being born in 2000! =P

Now, when I was little (I know that\'s not a very long time ago) I had just learnt the meaning of e=mc2, so I thought that if we travelled at C squared, all matter involved would be reduced to pure energy. Who knows? One of you nerds geniuses will be able to set me straight here...

*Insert elitist comment here about the 20th Century and the Millennium.*

The equation e=mc² only proves the concept of mass-energy equivalence. It doesn\'t mean that when travelling at the speed of light squared that mass will turn into energy.

Now, as for setting you straight; the equation e=mc², isn\'t a rule or a prediction of what happens. It just tells us the amount of energy that is in an object of mass m, using c² as a \'conversion factor\', it could be rearranged to tell us the mass of an amount of energy; m=e/c².

But to move away from the mechanics of the equation and onto what it can mean in reality; the equation was an important stepping stone in the road toward understanding the nuclear capabilities of matter around us. It also proved that concepts such as binding energy and the \'mass defect\' were in fact a reality, as well as further confirming theories such as the conservation of energy meaning that energy could not be created or lost, only turned into matter and vice versa.

The whole concept of mass-energy equivalence is a far too grand of a task to cover within one forum post and even more of one to try and convey it in a manner that a 12-year-old may understand, no offence intended of course. I suggest you read up on the subject online, or maybe a fellow forum member could provide more information, you could even ask a Science teacher at your School, they would be more than happy to help.

Remember, you should always fully understand and investigate everything you\'re taught, otherwise how can you teach it to others?

PS, if I made any mistakes in this post about mass-energy equivalence, please point them out.

Hope this helps.

[ping111]

*Insert elitist comment here about the 20th Century and the Millennium.*

The equation e=mc² only proves the concept of mass-energy equivalence. It doesn\'t mean that when travelling at the speed of light squared that mass will turn into energy.

Now, as for setting you straight; the equation e=mc², isn\'t a rule or a prediction of what happens. It just tells us the amount of energy that is in an object of mass m, using c² as a \'conversion factor\', it could be rearranged to tell us the mass of an amount of energy; m=e/c².

But to move away from the mechanics of the equation and onto what it can mean in reality; the equation was an important stepping stone in the road toward understanding the nuclear capabilities of matter around us. It also proved that concepts such as binding energy and the \'mass defect\' were in fact a reality, as well as further confirming theories such as the conservation of energy meaning that energy could not be created or lost, only turned into matter and vice versa.

The whole concept of mass-energy equivalence is a far too grand of a task to cover within one forum post and even more of one to try and convey it in a manner that a 12-year-old may understand, no offence intended of course. I suggest you read up on the subject online, or maybe a fellow forum member could provide more information, you could even ask a Science teacher at your School, they would be more than happy to help.

Remember, you should always fully understand and investigate everything you\'re taught, otherwise how can you teach it to others?

PS, if I made any mistakes in this post about mass-energy equivalence, please point them out.

Hope this helps.

Thanks a billion for this. No offence taken - I TL;DR\'d this thread, anyways.

Unfortunately, until I reach highschool, I\'m stuck with an idiot science teacher who probably only knows what she reads in her teacher\'s guide. She really couldn\'t explain this in the slightest. Maybe I can set up a 'scratch-your-back' system where I teach people things they wanna know, like languages, and they teach me science and more applied studies... Hmm...

[Ted]

Thanks a billion for this. No offence taken - I TL;DR\'d this thread, anyways.

Unfortunately, until I reach highschool, I\'m stuck with an idiot science teacher who probably only knows what she reads in her teacher\'s guide. She really couldn\'t explain this in the slightest. Maybe I can set up a 'scratch-your-back' system where I teach people things they wanna know, like languages, and they teach me science and more applied studies... Hmm...

That\'s not very good, I gather you\'re American so High School is usually for ~16-year-olds? That\'s quite a while, but maybe you could ask an older sibling or friend to investigate on your behalf.

I realised a simple anecdote that will help you understand the beauty and necessity of Maths after I had posted.

Maths is pretty much the only way you can articulate the manner in which sub-atomic matter, the Universe and everything in between operates. Did you see how much writing it took for CaptainArbitrary to convey the information about faster than light travel, relativity and geometry? Those concepts and relationships can often be expressed in a few equations with perfect accuracy and no room for misunderstanding once variables etc are explained.

The only hard part, as CaptainArbitrary said earlier, is wrapping your head around abstract concepts and theories. But I often think that in the coming years the concepts we find abstract now, will be trivial, I\'m sure that people once found the concept of breaking the sound barrier, and the physics that happens with that, to be abstract and now it is common knowledge.

Also, read the thread, it\'s worth it.

[ping111]

That\'s not very good, I gather you\'re American so High School is usually for ~16-year-olds? That\'s quite a while, but maybe you could ask an older sibling or friend to investigate on your behalf.

I realised a simple anecdote that will help you understand the beauty and necessity of Maths after I had posted.

Maths is pretty much the only way you can articulate the manner in which sub-atomic matter, the Universe and everything in between operates. Did you see how much writing it took for CaptainArbitrary to convey the information about faster than light travel, relativity and geometry? Those concepts and relationships can often be expressed in a few equations with perfect accuracy and no room for misunderstanding once variables etc are explained.

The only hard part, as CaptainArbitrary said earlier, is wrapping your head around abstract concepts and theories. But I often think that in the coming years the concepts we find abstract now, will be trivial, I\'m sure that people once found the concept of breaking the sound barrier, and the physics that happens with that, to be abstract and now it is common knowledge.

Also, read the thread, it\'s worth it.

Derp, Canadian, and high school is for 14-yr olds. =P Unfortunately, HS is gonna be a huge blast of knowledge for me, seeing how much Hebrew shit I\'ve been cramming my brain with incessantly.

Back on topic, I thank you kindly for understanding that no matter how much I want to see the map, I would never understand it until I\'m in at least university. Still can\'t make me read the thread - I don\'t have any duct tape to fix my brain. ;P

Cheers!

[Endeavour]

That\'s not very good, I gather you\'re American so High School is usually for ~16-year-olds? That\'s quite a while, but maybe you could ask an older sibling or friend to investigate on your behalf.

When does High School start in other countries? In America it starts on the 9th year, so 14-15 year old kids.

[ping111]

When does High School start in other countries? In America it starts on the 9th year, so 14-15 year old kids.

Same in English Canada - I think. In Quebec, HS starts in Grade 8, and there\'s only 3 years of college, so in between there\'s CEJEP, a 2-year program. Don\'t ask. ???

[Ted]

Derp, Canadian, and high school is for 14-yr olds. =P Unfortunately, HS is gonna be a huge blast of knowledge for me, seeing how much Hebrew shit I\'ve been cramming my brain with incessantly.

Back on topic, I thank you kindly for understanding that no matter how much I want to see the map, I would never understand it until I\'m in at least university. Still can\'t make me read the thread - I don\'t have any duct tape to fix my brain. ;P

Cheers!

Haha, that\'s fair enough, as long as you are willing to learn when the time comes, that\'s half the battle over with.

On a side note, for what reason are you learning Hebrew? I didn\'t think that religious studies was done in anywhere but Europe.

When does High School start in other countries? In America it starts on the 9th year, so 14-15 year old kids.

I always thought that High School was much like the British College or \'Sixth Form\' where you studied more specific subjects in the form of A Levels-equivalents for two years before going to University, but I guess it must be for four years and you study GCSE-equivalents as well. In Britain we start Secondary School in the 7th year when the students are ~11-12 and it goes all the way up to 16 or 18, depending on the school. Also,14-15-year-olds are normally in their 10th or 11th year as well, not sure what you guys spend the extra year doing, or whether we just start counting a year earlier. Hopefully the latter.

[ping111]

Haha, that\'s fair enough, as long as you are willing to learn when the time comes, that\'s half the battle over with.

On a side note, for what reason are you learning Hebrew? I didn\'t think that religious studies was done in anywhere but Europe.

It\'s a Jewish private school. However, I am incredibly agnostic in that I only keep my religion because I can, and follow very few practices. I\'ve actually started a mini-cult with a friend where we assume that Harry Potter is the Bible and basically follow its 'laws'. ;P

But that\'s off-topic. And hells yes, I\'m willing to learn! Imagine the looks on my bullies\' faces when they see me on the news, standing in front of the first mission for Mars One, headlined as '[NAME REDACTED] - Chief Engineer'!

[Endeavour]

I always thought that High School was much like the British College or \'Sixth Form\' where you studied more specific subjects in the form of A Levels-equivalents for two years before going to University, but I guess it must be for four years and you study GCSE-equivalents as well. In Britain we start Secondary School in the 7th year when the students are ~11-12 and it goes all the way up to 16 or 18, depending on the school. Also,14-15-year-olds are normally in their 10th or 11th year as well, not sure what you guys spend the extra year doing, or whether we just start counting a year earlier. Hopefully the latter.

I left out the year of Kindergarden and the optional 4 year old version of kindergarden. After Kindergarden it starts with grade 1, so it\'s a bit confusing. So technically the first year of high school is year 10.

[Hypocee]

Funny coincidence - Tom Francis of PCGamer UK and Suspicious Developments just threw together a prototype of Lorentz contraction/Time Dilation: https://docs.google.com/file/d/0B8VooG8MuLWERXE3d3p1SjZKQlE/edit?pli=1 and got pointed to Relativistic Asteroids: http://www.referencegames.com/classic.html

[hunter558]

In order to travel at the speed of light in normal space you need to have negative mass which is unknown to be possible. But the key to science is that there are numerous unknowns, just because we haven\'t proven Einstein wrong doesn\'t mean we never will. There are also theories such as the Alcubierre Drive(look it up) which would create a warp bubble and move space around the object in the bubble. This doesn\'t violate Einstein\'s laws but would still take an innumerable amount of energy to accomplish, and we dont know how to make warp bubbles either. It seems very bleak that FTL or even light-speed will ever be accomplished but there is so little we know, never give up hope.

[Phoxtane]

Well, to create negative mass, we\'d have to increase the mass until it hit such a point that it 'rolls over' to a negative mass, much like computing. I\'ve no idea if that\'s actually possible.

[Kryten]

Well, to create negative mass, we\'d have to increase the mass until it hit such a point that it 'rolls over' to a negative mass, much like computing. I\'ve no idea if that\'s actually possible.

Unfortunately, we don\'t live in a badly coded computer program, so that\'s impossible. Heck, even a bad program just rolls to zero and counts up again, it\'d have to be massively borked to start going backwards.

[CaptainArbitrary]

In order to travel at the speed of light in normal space you need to have negative mass which is unknown to be possible. But the key to science is that there are numerous unknowns, just because we haven\'t proven Einstein wrong doesn\'t mean we never will. There are also theories such as the Alcubierre Drive(look it up) which would create a warp bubble and move space around the object in the bubble. This doesn\'t violate Einstein\'s laws but would still take an innumerable amount of energy to accomplish, and we dont know how to make warp bubbles either. It seems very bleak that FTL or even light-speed will ever be accomplished but there is so little we know, never give up hope.

Negative energy, not negative mass. And negative energy IS known not to be possible. Construct a field Lagrangian for it and you\'ll see that it results in an unstable vacuum state. Any universe that permitted negative energy wouldn\'t exist for more than a single instant before collapsing.

And why does nobody read Alcubierre\'s paper all the way through? It\'s only four pages long, and the last page is where he explains that he\'s proven you CAN\'T create such a geometry in our universe.

[hunter558]

Negative energy, not negative mass. And negative energy IS known not to be possible. Construct a field Lagrangian for it and you\'ll see that it results in an unstable vacuum state. Any universe that permitted negative energy wouldn\'t exist for more than a single instant before collapsing.

And why does nobody read Alcubierre\'s paper all the way through? It\'s only four pages long, and the last page is where he explains that he\'s proven you CAN\'T create such a geometry in our universe.

I believe its negative mass actually because photons are zero mass(or extremely close to it) and therefore travel at the speed of light, a negative mass object could be propelled at even faster speeds. Negative Energy is more along the lines of anti-matter which does indeed collapse and i never read Alcubierre\'s paper but would indeed like to, i just know of his theories. You speak in such finiteness however that its almost unscientific of you, many scientists say they would love to believe in god if there was any proof he/she or it existed for example. Very few things in science are fact, all simply theories no matter how much proof is for or against them, anything is possible.

[sal_vager]

hunter558, Alcubierre\'s paper can be downloaded for free from the Cornell University Library.

It\'s only 10 pages it seems.