Things I learned in physics class

POSTED BY: BadgersHat
UPDATED: Friday, August 12, 2005 15:00
VIEWED: 25158
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SIGMANUNKI

Sunday, July 17, 2005 3:12 AM

Quote:
Originally posted by Finn mac Cumhal:

Actually there is a little criterion concerning zero mass. To travel at speed of light something must have zero mass, otherwise momentum becomes infinite at the speed of light. And beyond the speed of light, the mass must be negative. If you assume negative mass is meaningful and extant, then a massive objective simply cannot accelerate (or decelerate) to the speed of light.

So if you don’t rule out magic, a lot of possibilities open up.

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Qui desiderat pacem praeparet bellum.

I was just not discounting future developments. Things do change radically from time to time.

*sigh* I've spent too much time in pure math. Going to have to refresh my physics.

----
"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show

SIGMANUNKI

Sunday, July 17, 2005 3:23 AM

@FourSkys:
Also, according to Dr. Greene's infomercial, string theory doesn't allow for wormholes.

I have no doubt that science cannot be its own undoing. It will evolve as it makes new discovers and perhaps in a few centeries, it'll look very different.

I would think that the only part science may play in mankinds undoing, is when some dumbass gets hold of something that they don't understand and mis-uses it. My only hope is that, as a race, when we get far enough when that becomes possible, that we've learned enough that that is highly unlikely.

@Zoid wrote:
"""
but, QM says you can't know, so don't bother asking. Yikes.
"""
I would think that it would be more appropriate to say that we are just coming to start to understand what QM says. Maybe in the next few decades some questions will be answered. But, I would gather that more tougher questions would be added to the list.

And physics is not faith.

From the wife:
QM does not say that you cannot know about the underlying framework, it only places limitations on how much you can know.

----
"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show

SIGMANUNKI

Sunday, July 17, 2005 3:56 AM

Zoid wrote:
"""
Likewise, even though most scientists engaging in these endeavors adhere to Dirac's commandment, "Just shut up and calculate",
"""

In my experience, knowning people pesonally from 3 Universities. Most? No. Some? Yes.

Zoid wrote:
"""
I don't like being told what to think.
So, I'll just stick to reading the available literature and having fun wondering about the universe. Youse guys can have the formalism and 'don't ask questions' ground rules. I couldn't turn off my imagination if I tried.
"""

From the wife:
This is exactly why a lot of people go into the science; because they are questioning things. It's an important part of the scientific culture to question things but on the other hand to know where it makes sense to rely on other peoples results. Knowing the difference and being able to do both is exactly what makes a good scientist. The bad ones are those that never question things.

Applying the formalism to find out more about the universe actually makes it more fun. Reading pop science books is (with very few exceptions) like watching a movie with the sound turned off: you get some vague ideas, you see some pretty pictures, but you don't understand what it's all about.

----
"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show

ZOID

Sunday, July 17, 2005 4:41 AM

SigmaNunki:

Some movement away from the precipice of our dis-communication, perhaps? I welcome that.

You wrote:

Quote:
...Applying the formalism to find out more about the universe actually makes it more fun. Reading pop science books is (with very few exceptions) like watching a movie with the sound turned off: you get some vague ideas, you see some pretty pictures, but you don't understand what it's all about.

...But not everyone can be a physicist. Who would carry away the trash? Who would keep the peace on our streets? Stop our houses from burning down? Keep our skies (and airport terminals

) safe? Go to the jungles of PNG to provide desperately needed medical services? (NB: With a tip o' the tam to minime, whom I'm still sending regular updates of FFFn. Browncoats might consider emailing her sometime. She's terribly isolated. How would you like to be stuck in the boondocks watching 4-year olds die of curable illnesses, with only zoid emailing you? *shiver*)

What about the rest of us non-physicists? Should we just mind our own business, if we haven't been schooled with the rod of formalism? Can we lesser humans not wonder and seek knowledge, too? If we ask those who have traveled such paths what they have found along their way, can we only expect to be told that we could never hope to understand?

Maybe so. In which case, perhaps we must settle for a "movie with the sound turned off", or else live in darkness...

Respectfully,

zoid

THEGREYJEDI

Sunday, July 17, 2005 5:35 AM

Quote:
Originally posted by Finn mac Cumhal:
Quote:
Originally posted by SigmaNunki:
Also, with regards to the faster than light thing. The only thing that is stated is that things can't accelerate to the speed of light. It says nothing about things already at the speed of light and/or beyond. Nor does anything state that there isn't another way to get to speed without acceleration. It's just that that is the only way we know how right now.

That being said, there is nothing to indicate that there is another way to get to speed aside from accelerating.
Actually there is a little criterion concerning zero mass. To travel at speed of light something must have zero mass, otherwise momentum becomes infinite at the speed of light. And beyond the speed of light, the mass must be negative. If you assume negative mass is meaningful and extant, then a massive objective simply cannot accelerate (or decelerate) to the speed of light.

So if you don’t rule out magic, a lot of possibilities open up.

-------------
Qui desiderat pacem praeparet bellum.

Which is why I like my idea. If we can pop into the fourth dimension, we could travel distances along the same position in time. Likewise same position in space, different position in time. Just hope you don't travel to a position in time or space where there's, say, an orbiting planet or star. That'd end your day real quick. At least all that's my little theory. I have no clue what the scientific relevance of the whole thing is. Might all be hogwash. But it would solve the acceleration/zero mass issue.

--------------------------------------------------------------
Chief Engineer - USS SereniTREE
http://tomeofgrey.blogspot.com
Real Fans Wait - 09/30/05

THEFORGE

Sunday, July 17, 2005 7:52 AM

Quote:
Originally posted by StarPilotGrainger:
"Remember, the enemy's gate is down."

Ender's Game RULES! ...yo Grainger, go nova!

I like your idea about constant 1g acceleration, though I'd have to sit down and do the math (after remembering) to figure out how long it would take you to get to any significant speed. As far as your thought of a brief period of freefall: You could simply have your ship make a wide turn using some sort of RCS - without cutting the main drive - until it pointed in the opposite direction. That would eliminate any weightlessness. If you stretched that manouver out over a long enough period of time, the passengers/crew would barely notice the change in direction.

Orbiting a planet would present a difficulty to this method of artificial gravity...with centrifugal/centrepital forces being equal, you're back to freefall. Bah!

(Oh well...freeze your shooting arm, freeze those knees, blast the other toon to pieces!)

"The Killing Sword...The Life-Giving Sword"

BARKINGDOC

Sunday, July 17, 2005 9:21 AM

This doesn't have very much to do with any advanced concepts of physics: Just addressing the fuel issue in Firefly (and possible real travel)--- whatever you ultimately discover about propulsion and velocity, it appears to me that Serenity draws all of its power, including life support, from it's engine, which runs on fuel. Direct fuel is always going to be the easiest and most bang-for-your-buck way of powering any motorized vehicle (as opposed to batteries or something else less efficient and reliable) so it seems like a legitimate concern--- at least from a storytelling standpoint, but also probably from a real world perpective as well. If you are building a single craft to perform a single trip in a single direction, then a single launch and stored energy would be groovy. But a Firefly wants to keep flying forever, wherever it wants to go, as well as being a home to those on board. And that means money for gas, baby, however you can get it.

As for velocity and fusion and all the other science, I absolutely love talking about it, and I hope that as long as Firefly/Serenity lives such things NEVER become a part of the story in the ridiuclous ways they have on other sci-fi. I for one am happy to know the engine runs and they use some kind of fuel for it. Including silly psuedo-science just makes stories less and less about real humans living their lives.

God grant me steel to protect the folks I cannot charge,
the cash on hand to charge the folks I can,
and the wisdom to know when to break for it.

ZOID

Sunday, July 17, 2005 3:25 PM

BarkingDoc:

I -- along with many others -- am intrigued by the gravitational aspects of Serenity's (and every other ship in the 'verse?) propulsion and environmental systems. It has been suggested that it's just a convenience to keep the actors from having to deliver lines while floating around the ship, as in every other sci-fi property from Star Trek to Star Wars and beyond.

But the author(s) have gone out of their way to include terms like 'grav boot' when describing Serenity's drive, and in the pilot, Mal and his cohorts are weightless -- as are the crates they are towing -- until they reenter Serenity and close the cargo door, at which time the crates fall to the deck. When Mal and Zoe describe the terraforming efforts on the Rim (again from the pilot), she says, "...All those moons -- just like the central planets, they're as close to Earth-That-Was as we could make 'em: atmosphere, gravity and such, but..." (emphasis mine). Something purposeful is going on as regards artificial gravity, or else the writers -- including JW in the pilot -- are going out of their way to rub our noses in a convenient dramatic device. And the gravity stays on, even when Serenity's drive is disabled ("Out of Gas")...

This is why I always figured Mal's homeworld of Shadow was destroyed by the Alliance simply turning off the planet(oid)'s gravity generator(s). Just let the atmospheric gases explode away from the surface under their own pressure, once the Earth-normal gravity was turned off. That'd be a nasty way for an entire planetoid's ecosystem to die...

Respectfully,

zoid

P.S.
I've always playfully thought the sequels to "Serenity" should be "Shadow" and "Firefly". Did anyone read Joss' post about Summer portraying Kitty Pryde in X3? He mentions the sequels as: "SERENITY II: RICARDO MONTALBAN'S STILL PISSED" ("Wrath of Khan" reference, for the uninitiated) and "SERENITY III: SO VERY NUDE". I definitely like his 3rd idea better than mine...
_________________________________________________

"Burn the land and boil the sea..." -The Ballad of Serenity

SIGMANUNKI

Wednesday, July 20, 2005 5:28 AM

@zoid:
Dude, you missed my point enitrely (as you have all along).

First off, it was my wife that wrote that, not me. And that was just to say, that we should all know the limitations of what we know/our capabilities/etc. ie I'll never write a great novel, but I probably stand to do some good work in math or physics or...

Second, I never stated that you couldn't know, but that you don't. And I stated this explicitly above. Please read my posts, I don't think that I should have to state this yet again.

Thirdly, I don't expect everyone to be a physicist. Just that they accept that the don't actually know and acknowledge there limitations (which you've yet to actually do).

Asking questions is always a good thing. Giving answers is a good thing as well. It is never bad when knowledge is spead. My problem is when people spread clear dis-information (well, clear to those who know).

Now, I don't expect the average Joe to know that they don't understand if they indeed don't, as they typically don't have someone who actually knows to bounce what they think off of.

But when these people spread what they think (which is wrong) around, that is when I step in (or try to anyway) to correct the situation when I can.

The actual problem comes in when the people that don't know take offense and don't acknowledge that they don't know crying foul and such.

This is my problem with you. In that last thread I proved that you didn't know what you were talking about and you freaked out. You lashed out at me not even taking the time to assimilate the correct information. Which you are actually doing again now in a less agressive fashon than before.

So, ask away. Just don't get pissy when someone proves you wrong/corrects you/etc.

----
"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show

SIGMANUNKI

Wednesday, July 20, 2005 5:33 AM

Quote:
Originally posted by BarkingDoc:

As for velocity and fusion and all the other science, I absolutely love talking about it, and I hope that as long as Firefly/Serenity lives such things NEVER become a part of the story in the ridiuclous ways they have on other sci-fi. I for one am happy to know the engine runs and they use some kind of fuel for it. Including silly psuedo-science just makes stories less and less about real humans living their lives.

I entirely agree. Leaves a lot of room for story, instead of the inconsistancies that will creep in otherwise.

----
"Canada being mad at you is like Mr. Rogers throwing a brick through your window." -Jon Stewart, The Daily Show

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