Astrophysics: the relativity of time

General scientific debates. Presentations of new technologies (not directly related to renewable energies or biofuels or other themes developed in other sub-sectors) forums).
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963




by Ahmed » 17/12/14, 16:22

Obamot, the "conquest of space" is obviously a commercial and highly fanciful presentation and we are durably *, as a species, under house arrest on our planet, without any prospect of escape, especially since it would not be "enough" not to transport "only" humans, but also all the other species essential to our survival (and, in saying that I am not thinking of the Christmas turkey, you bunch of greedy!).

You seem a bit depressed to me, this is not the time, with the approach of the Trade Fairs and its parade of nonsense ... Hold on!
To cheer you up, and in the style of your message, here is one of the definitions that Desproges gave death: it is when the right of man is erased before that of the maggot.


* From a technical point of view which does not prejudge our capacity to last; what is important is that fleeing is not an option as a solution to the destruction of living conditions on earth ...
0 x
"Please don't believe what I'm telling you."
User avatar
Capt_Maloche
Moderator
Moderator
posts: 4559
Registration: 29/07/06, 11:14
Location: Ile-de-France
x 42




by Capt_Maloche » 17/12/14, 19:08

Gaston wrote:Result which obviously does not take into account the relativistic effects that will manifest themselves after a few months of acceleration.

The formula which gives the speed of an object subjected to a constant force F is:

V = gt / rac (1 + g²t² / c²) with g = F / m

In the above case, after 353 days the speed will be "only" 212 132 031,7 m / s

To reach 99% of the speed of light, it will take 214615410 seconds or 408 years ...


Very complicated this formula for a constant acceleration, are you sure of yourself? can you identify the units?

In fact we don't care about the force, it depends on the mass of the vessel
To simplify a thrust representing an acceleration of 9.81 m / s² allows to consider an ideal artificial gravity, with a simple calculation: a speed of 9.81 m / s more every 1 seconds
0 x
"Consumption is similar to a search consolation, a way to fill a growing existential void. With, the key, a lot of frustration and a little guilt, increasing the environmental awareness." (Gérard Mermet)
OUCH, OUILLE, OUCH, AAHH! ^ _ ^
User avatar
Capt_Maloche
Moderator
Moderator
posts: 4559
Registration: 29/07/06, 11:14
Location: Ile-de-France
x 42




by Capt_Maloche » 17/12/14, 19:19

Ahmed wrote:Obamot, ... especially since it would not "be enough" to transport "only" humans, but also all the other species essential to our survival (and, in saying that I am not thinking of the Christmas turkey, band gluttonous!).


Are you thinking of females? :D
0 x
"Consumption is similar to a search consolation, a way to fill a growing existential void. With, the key, a lot of frustration and a little guilt, increasing the environmental awareness." (Gérard Mermet)
OUCH, OUILLE, OUCH, AAHH! ^ _ ^
User avatar
Capt_Maloche
Moderator
Moderator
posts: 4559
Registration: 29/07/06, 11:14
Location: Ile-de-France
x 42




by Capt_Maloche » 17/12/14, 19:26

Obamot wrote:
Long live the belief in science which is in the process of replacing that which we had in "god"! : Mrgreen: : Cheesy: 8)

Long live man and ruchti graben (!) which brings us back to the autism intrinsic to our species! Image

And since they remind us of the faults of humanity: "long live the terrorists»Threatening to blow himself up then eliminated / executed with machine-gun fire in a democratic state with parliamentary justice - without trial and without anyone judging the disproportion of the facts given the threat and the expeditious methods used - in the mood hushed up the swanky chocolates of the Judeo-Christian aristocracy in the middle of the business district ... of our kind, which can only be a real masterpiece of evolutionary theory (I am no more neither creationist nor for Daesh or the National Guard ...! No, we will need even more " muscular "than that to understand our drifts ...?)

Roughly speaking, in the current situation, we are not much better!


Oh man of little faith : Cheesy:

So say, you let go, and we didn't offer you chocolate, it looks like :P
0 x
"Consumption is similar to a search consolation, a way to fill a growing existential void. With, the key, a lot of frustration and a little guilt, increasing the environmental awareness." (Gérard Mermet)
OUCH, OUILLE, OUCH, AAHH! ^ _ ^
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963




by Ahmed » 17/12/14, 20:09

No, Capt_Maloche, because half of the men are women! :D
0 x
"Please don't believe what I'm telling you."
User avatar
Obamot
Econologue expert
Econologue expert
posts: 28725
Registration: 22/08/09, 22:38
Location: regio genevesis
x 5538




by Obamot » 18/12/14, 01:44

: Lol:

Capt_Maloche wrote:
Obamot wrote:
Long live the belief in science which is in the process of replacing that which we had in "god"! : Mrgreen: : Cheesy: 8)

Long live man and ruchti graben (!) which brings us back to the autism intrinsic to our species! Image

And since they remind us of the faults of humanity: "long live the terrorists»Threatening to blow himself up then eliminated / executed with machine-gun fire in a democratic state with parliamentary justice - without trial and without anyone judging the disproportion of the facts given the threat and the expeditious methods used - in the mood hushed up the swanky chocolates of the Judeo-Christian aristocracy in the middle of the business district ... of our kind, which can only be a real masterpiece of evolutionary theory (I am no more neither creationist nor for Daesh or the National Guard ...! No, we will need even more " muscular "than that to understand our drifts ...?)

Roughly speaking, in the current situation, we are not much better!


Oh man of little faith : Cheesy:

Arf! Erected hypotheses between astronomy / origins and ...end of the world: this thread inspires! ;)

(Hence this vitriolic prose ... Because guess a little what we would be closest!) : Mrgreen:

I have not yet spoken of the wisdom of the lesson-givers of the planet, and altruistic to the highest point since they generously share their wars and their debt (worth half of the world's GDP through petrodollars and political assassinations. ..) A model for "humanity" without doubt exemplary when it compares itself ... to itself (there would be "we"on the one hand which we take for god since the advent of the higgs bosons VS the"nature"on the other) we live in a formidable age of blind people in which one-eyed navelists rule the law ...!

Capt_Maloche wrote:So say, you let go, and we didn't offer you chocolate it looks like :P

I don't care: if we remain passive, it is we who will find ourselves ... chocolates! :P

*) And I don't see why we had to tackle kosher chocolate when there is ḥalāl ... >>> Come on, let's keep hitting each other with drones and human bombs, and close our eyes, we may well end up getting there to ... disappear ... Because going through a wormhole, if so is that one day we would acquire the techniques (and not just a theoretical fantasy) we still have to live and last until then ... And as it will be imperative to have everything "managed" on Earth so that the mankind outlasts itself, perhaps we will no longer even have the urgent need to go elsewhere to escape our destiny, deep down.
0 x
User avatar
Gaston
Econologue expert
Econologue expert
posts: 1910
Registration: 04/10/10, 11:37
x 88




by Gaston » 18/12/14, 09:58

Capt_Maloche wrote:Very complicated this formula for constant acceleration,
I said constant strength.
In classical mechanics constant force is equivalent to constant acceleration, but not in relativism because to have a constant acceleration, one would need a force which increases with speed (since the apparent mass increases).

Capt_Maloche wrote:Are you sure?
Yes.

We can verify that
  • for t "small", g²t² / c² is very small in front of 1, so 1 + g²t² / c² is close to 1 and we find V ~ gt.
  • when t tends towards infinity, V tends towards c.

Capt_Maloche wrote:can you identify the units?
Yes.
g in m / s²
t in s
c in m / s (speed of light in a vacuum)

so
g²t² in m² / s²
g²t² / c² without unit
Rac (1 + g²t² / c²) without unit

Therefore V homogeneous at gt in m / s.



Capt_Maloche wrote:In fact we don't care about the force, it depends on the mass of the vessel.
To simplify a thrust representing an acceleration of 9.81 m / s² allows to consider an ideal artificial gravity, with a simple calculation: a speed of 9.81 m / s more every 1 seconds
Yes, in classical mechanics.
In relativist, as the apparent mass increases, maintaining a constant acceleration supposes a propelling force which can increase until infinity.
This is what would make it possible to reach the speed of light in a finite time.
0 x
User avatar
Capt_Maloche
Moderator
Moderator
posts: 4559
Registration: 29/07/06, 11:14
Location: Ile-de-France
x 42




by Capt_Maloche » 18/12/14, 12:00

So you mean that the mass of an object increases with its speed in a vacuum? the Lorentz factor? I forgot that

Silly question, a guy in a capsule who takes 1G will see his mass increase (and therefore his apparent weight) in what proportion according to his speed?

Would you be able to integrate this relationship into the formula that you presented?

Mass Speed ​​Relation
Last edited by Capt_Maloche the 18 / 12 / 14, 13: 59, 1 edited once.
0 x
"Consumption is similar to a search consolation, a way to fill a growing existential void. With, the key, a lot of frustration and a little guilt, increasing the environmental awareness." (Gérard Mermet)
OUCH, OUILLE, OUCH, AAHH! ^ _ ^
User avatar
Capt_Maloche
Moderator
Moderator
posts: 4559
Registration: 29/07/06, 11:14
Location: Ile-de-France
x 42




by Capt_Maloche » 18/12/14, 13:54

Not to mention that it becomes fun, because we are moving in our universe at the rate of expansion (constant of Hubble) of 72 km / s / mgpsc 1 megaparsec = 3.5 light year if I read correctly

Diantre we accelerate therefore compared to a hypothetical zero point, and our mass would be affected, to what extent? : Cheesy:
0 x
"Consumption is similar to a search consolation, a way to fill a growing existential void. With, the key, a lot of frustration and a little guilt, increasing the environmental awareness." (Gérard Mermet)
OUCH, OUILLE, OUCH, AAHH! ^ _ ^
User avatar
Gaston
Econologue expert
Econologue expert
posts: 1910
Registration: 04/10/10, 11:37
x 88




by Gaston » 18/12/14, 15:07

Capt_Maloche wrote:Silly question, a guy in a capsule who takes 1G will see his mass increase (and therefore his apparent weight) in what proportion according to his speed?
The moving mass (M) is linked to the mass at rest (m) by the relation:
M = m / (1-v² / c²)

Capt_Maloche wrote:Would you be able to integrate this relationship into the formula that you presented?
It is integrated, precisely by the fact that a constant force produces an acceleration decreasing with speed.
0 x

Back to "Science and Technology"

Who is online ?

Users browsing this forum : Macro and 190 guests