I understand that you need a deflector shield to clear a path in front of your starship when travelling at relativistic speeds, such as under impulse drive.    However, since the idea of warp drive is that you create a warp bubble around your ship and compress the space in front of you while expanding it behind you (basically moving the bubble of space that you're sitting in through space) then why do you need a deflector shield?  You're not moving relative to the space you're occupying.    Any particle in your path would just get pushed out of the way temporarily as you pass by.  That particle wouldn't even move relative to the space it's occupying... the space it's occupying would just get warped.    Now I can't imagine it's good for matter to exist in a highly warped area of space.  I imagine any macroscopic bit of matter entering a highly curved area of space would have a lot of internal stresses and absorb a lot of heat, perhaps becoming plasma, so perhaps the deflector shield actually deflects particles out of the path of the warp bubble itself.  That energy has to come from somewhere, which has to be the warp drive itself.  If it didn't take energy to warp through matter then you could theoretically warp right through a planet or a star without worrying about it, but that's clearly not possible.  Are there any canon explanations for why a deflector shield is needed at warp?
121981
Like something going at warp hits a planet, star, another ship, moon, satellite, alien, tribble, etc.... Basically, can stuff in subspace (warped stuff) hit stuff in real space (not warp)?  Star Trek: The Voyage Home shows us clearly that entering warp speed within Earth's atmosphere has no adverse consequences for the starship or the environment.  HMS Bounty went through miles of atmosphere, dust, birds, and clouds and nothing entered  to hit her. Enterprise did this again by dropping out of warp in Titan's atmosphere.  which explains some tech used, but now we have to ask if there is even a hazard of collision at warp. Has there ever been a collision in the franchise - any normal object being hit at warp speed? (This obviously doesn't include things traveling at warp together, like photon torpedoes from one ship to another).  Closest example I found: In  Enterprise attempts warp before balancing their warp drives and creates a wormhole instead. They nearly collide with an asteroid which was already inside the wormhole, but neither the ship not the asteroid were traveling at warp.  Compressing Space Real-world (non-canon) attempts to explain ST warp technology rely on compressing space itself in front of the vessel. The image sequence below from Star Trek: Into Darkness (canon) shows Enterprise warping past the USS Vengeance and confirms that Enterprise actually gets smaller (or compresses the space around it). The light on Vengeance shows that at the instant the two ships are side-by-side Enterprise looks like a toy beside it. (Large image needed for detail - sorry):    Thus objects at warp occupy less real space - possibly none at - because , which according to Memory-Alpha is implied to be the medium which FTL travel happens. Normally subspace and real space do not interact. When they do it is called a .  Also, objects inside the warp bubble are not moved by the warp drive:     The observer(spaceship) is still immersed in the interior of the warp bubble and this bubble is carried   out by the spacetime ”stream” at faster than light velocities with the observer at the rest with respect to   its local neighborhoods  (p. 25)   It is my belief that to be consistent with warp bubble physics derived from the Einstein Field Equations in general relativity, the ST interpretation of warp speed travel should not allow collisions between n-space objects and objects within a warp bubble and remove the phenomenon from any plotlines such that warp travel is intrinsically safe for the traveller, but possibly greatly impactful for the normal world outside.  But has it happened?  Points of clarification raised by comments  Deflector Shields: Yes, ships have them. Gene Roddenberry envisioned Navigational Shields which would deflect anything in front of the ship, from a single hydrogen atom to an asteroid (see his notes below).    It's important to note that much of what he had in this guide was changed in final production. In fact, based on this guide we could write an entire episode on a simple deflector sabotage resulting in them hitting a hydrogen atom. Real science calculations tell us that even hitting a photon of light would release incalculable energy.  These notes very much explain the many questions asking why ships don't go to warp inside a solar system. Solar systems are FULL of particles and debris, which would require a great deal of energy to deflect. Interstellar space simply draws less power because the shields work less.
49057
I understand that the event horizon of a black hole forms at the radius from the singularity where the escape velocity is $c$. But it's also true that you don't have to go escape velocity to escape an object if you can maintain some kind of thrust. You could escape the earth at 1 km/h if you could maintain the proper amount of thrust for enough time. So if you pass just beneath the event horizon, shouldn't you be able to thrust your way back out, despite the $&gt;c$ escape velocity? Or does this restriction have to do solely with relativistic effects (time stopping for outside observers at the event horizon)?
103087
The thought randomly occurred to me that a circular particle accelerator would have to exert a lot of force in order to maintain the curvature of the trajectory.  Many accelerators move particles at fully relativistic speeds, and I want to ask how that affects things.  Why does this matter?  Well, if I understand correctly, a particle in the LHC moving at $0.999 c$ would be dramatically more difficult to keep moving in the circle than a particle moving at $0.99 c$.  Reading Wikipedia, I was delighted to find a fully specified problem within a single paragraph.       The LHC lies in a tunnel 27 kilometres (17 mi) in circumference, as deep as 175 metres (574 ft) beneath the Franco-Swiss border near Geneva, Switzerland. Its synchrotron is designed to collide opposing particle beams of either protons at up to 7 teraelectronvolts (7 TeV or 1.12 microjoules) per nucleon, or lead nuclei at an energy of 574 TeV (92.0 µJ) per nucleus (2.76 TeV per nucleon).   I can (or Google can)  the proton case to come to $0.999999991 c$.  In order to correctly calculate the force that the LHC must exert on it, do I need to start from $F=dp/dt$, or can I get by with $v^2/r$ times the relativistic mass?  I'm not quite sure how to do the former.  Question: Say I have 2 protons, both moving so fast they're going almost the speed of light but one has twice the energy of the other.  They move side-by-side and enter either an electric or magnetic field that causes them to accelerate perpendicular to the velocity vector.  Is the radius of curvature mostly the same for the two, or is it different by a major factor (like 0.5x, 1x, or 2x)?  I want to read some comments from people who understand these physics well.  The particles beyond a certain energy are all going almost exactly the same speed.  Is it still okay for me to say they have the same "acceleration" too?  They just happen to have absurdly huge inertia compared to the same particle at a more modest fraction of the speed of light.  Is this the correct perspective?
41591
I've been wondering, what causes the normal force to exist?  In class the teacher never actually explains it, he just says "It has to be there because something has to counter gravity."  While I understand this is true, it never explains why.  Whenever I ask anyone else they always respond in a similar way, saying "It has to be there, because the object is not accelerating", and this has become very frustrating.  So what is the cause of the normal force? From my reasoning, it has to be one of the four fundamental forces. (Gravity, electromagnetism, the weak force, or the strong force).  It would seam to me that electromagnetism would make to most sense (electrons in the outer shells of atoms repelling each other),   However, just as I thought this had to be right, I read a thing online about "certain fundamental particles repelling each other when their wave functions overlap".  I haven't studied quantum mechanics yet so I'm not really sure what to make of that.  If anyone could shed some light on this for me it would be much appreciated.
116755
Wikipedia describes  as      a form of spacecraft propulsion using a combination of light and high speed ejected gasses from a star to push large ultra-thin mirrors to high speeds.   I understand the part where ejected gasses bump into the sail pushing the spacecraft. On the other hand, I don't understand how light can do this, since light has no mass.  How does that work? Does this mean that if I have a mirror balancing on a needle I would be able to push it over with my flashlight?
65200
Wikipedia has this page on  using planets. In some cases this effect was used to accelerate the spacecraft to a higher velocity. This diagram shows this in a very oversimplified manner.   That got me thinking that if light is affected by gravity, and if it slingshots around the black hole/massive object, can't it gain a higher speed than $c$? What limitations are stopping it from doing this?  Forgive me if the answer to this question is pretty straight-forward or staring-you-in-the-face kind. I haven't fully understood the mechanics of the gravitational slingshot fully yet, but I couldn't wait to ask this. Note: If it is possible (I highly doubt that!), could you provide an explanation using Newtonian mechanics, I'm not very familiar with general relativity because I'm in high school.
118566
When the good ship Serenity is traveling in deep space, the crew experiences what looks like an Earth-normal (or Earth That Was-normal) level of gravity. Is it ever explained how the ship is able to generate artificial gravity? The ship doesn't spin, so  is out.  is a possibility, but I think the gravity in the ship pulls in a direction that is perpendicular to the direction the ship is usually traveling in, not opposite, like this method would require.   So: how does she pull it off?   Extra credit: how does she pull it off in the episode ? Serenity's engine is totally dead, to the extent where not even life support systems are online. Yet Mal still has to valiantly haul himself around on the floor to replace the compression coil, so whatever creates the artificial gravity on Serenity is clearly still going. How?
51802
(This question is related to , and was originally posted as an answer there, but it's not the same)    In , the Empire attacks Rebel Echo Base located in Hoth. The Rebels are alerted before the attack, and raise some sort of shield to prevent orbital bombardment of their base. The Empire is then forced to deploy land forces to first disable the shield generator, before destroying the base. Presumably, the Imperial forces are deployed using dropships.  My question is about how the Rebel shield generator works, and how the Imperials manage to bypass it.  I think the shield generator is something of a plot hole. At first I incorrectly thought it was a planetary shield (i.e. a shield around all of Hoth) preventing orbital bombardment, and also preventing any dropships (with their AT-AT payload) from landing, but I think : the  states it is an energy field around just an area of Hoth, presumably Echo Base:     VEERS: My lord, the fleet has moved out of light-speed. Com-Scan has   detected an energy field protecting an area around the sixth planet of   the Hoth system. The field is strong enough to deflect any   bombardment.   So my initial objection ("how did the Imperial dropships bypass the shield?") has been answered: they didn't. They landed outside the energy field to deliver the AT-ATs. But now I have another question: does an AT-AT have to walk inside the field to fire at the generator, or can it fire into the field from outside?  Maybe the field simply cannot stop matter, only energy weapons (therefore preventing orbital bombardment), in which case the AT-ATs would be able to just walk inside. However, the script also states:     LEIA: All troop carriers will assemble at the north entrance. The   heavy transport ships will leave as soon as they're loaded. Only two   fighter escorts per ship. The energy shield can only be opened for a   short time, so you'll have to stay very close to your transports.   So it's clear that the energy field is also capable of stopping matter, in this case troop transports and fighters. It follows that it should also prevent AT-ATs from walking through it. So the only way I can see the walkers disabling the generator is by firing into the energy field!  This would mean the field is strong enough to stop matter such as ships and fighters, and energy weapons used for orbital bombardment (and also the Ion Cannon the Rebels use as an anti-orbit battery: Leia also states they must lower the shield to use it), but not able to stop whatever energy weapons the AT-ATs use!  So how on Earth did Imperial Walkers manage to disable the shield generator?
120891
The  entry on Memory Alpha states that photon torpedoes are warp-capable. Under the technical specs it says that photon torpedoes launched from a vehicle traveling at warp will remain at warp, but will not accelerate to warp if launched from a sub-light vehicle.   In  when it appears to ^Captain Riker that they would not be able to stop the cube he orders Acting Ensign Crusher to set a collision course with the cube at warp 9.  This is the only time I can think of a ship using their warp technology in an obviously offensive way. To me it seems like throwing objects at faster than light speeds at targets would be incredibly devastating.   Are there any other examples or weapons when someone uses warp technology as a weapon?  ^ At this time he had a field commission rank of captain.
44670
This is really bugging me. When you look up some educational text about stars life, this is what you find out:   Gravity creates the temperature and pressure to start fusion reactions. The fusion proceeds to heavier and heavier cores ending with iron, which remains in the centre of the star. One moment, all light cores are depleted and the gravity wins over the power of the fusion reactions, now absent. The core of the star collapses into high density object, which may vary depending on the star mass. And the top layers of the star explode.   And I just cannot find clear explanation why. According to what I imagine, the top layers of the star should just fall into the collapsing core.  Is that because of the 3rd Newtons rule?  Or do the stars have some need to end with a cool boom?
20172
In the middle of , the crew of the Enterprise-D is flying on a rescue mission toward Bersallis III, to save a Federation outpost from an impending fire-storm.  Upon reaching Bersallis III’s system, the ship drops out of warp. During senior officers meeting Riker states that it will take another hour to reach Bersallis III, so LaForge's team will have another two hours for a rescue transportation. When Riker tells this, we can clearly see, through windows behind him, that the ship is indeed travelling on conventional engines.  Why? Wouldn't it be more efficient in terms of rescue mission, to fly in warp until reaching the planet and not to waste another hour of precious time travelling?
24467
What is the exact reason that normal matter can not exist within an event horizon?  I can understand how a super-dense object like a neutron star could accrete mass until its physical radius is less than its Schwarzschild radius and an event horizon forms around it.   But why can't the neutron star remain inside the event horizon as it was before the event horizon formed? Aside from the escape velocity at the surface reaching $c$, what actually changed?  Why must all matter within an event horizon undergo complete physical collapse to a point?
81790
In Star Trek Into Darkness, the Vengeance was able to catch up to the Enterprise and attack it while in warp.   According to the , warp is a bubble around a specific ship. This would explain why Kirk was so surprised when it happened.   How was the Vengeance able to catch up, or get into the Enterprise’s warp bubble?
14344
We know, the rockets in space use Newton's 3rd law to increase their velocity and hence move. What I don't understand is how it is possible in space aka vacuum-state without air? From what I know, Joule's "Free Expansion of Gas" says that free-expansion compresses the gas and is therefore "affected" by vacuum so it can't make the rocket move as the gas will have zero press/force. Could someone please explain me how rockets do really work and the above-mentioned statement?   Actually, please have a look at this site:   Not: The site appears to include some conspiracy theory thingummies, but made me wonder anyway.
92404
Once the Rebel fleet showed at Endor there was no need for stealth operations.  Soon after arriving, the Rebels discover the stealth mission was not successful and begin a battle over the moon of Endor.  Why did the Rebels not use their ships to attack the shield generator?  Looking a the hologram displayed on Home One, the shield only covers Death Star II, not the moon. Furthermore, the shield generator's location on the Moon would not be hard to find as it had to be within the proximity of Death Star II and stood well above the tree line. It seems that even a few X-wings, B-wings or Y-Wings could have made short work of the Tower.  One possible answer is that the Tower was also protected by a shield. Okay, but they would not even attempt to bomb it?   Perhaps the location of the strike team was unclear and they did not want to risk the lives of the Strike team. If this was the case, why did they not target the tower or the dish to disable the shield projector unit?
101437
So I've watched pretty much all the Star Treks and from what I've seen, Star Trek officers don't wear any protective gear! Why don't they wear any kind of armor like the Klingons? Is it because the weapons are so powerful that it doesn't matter if you wear armor or not? Ex: You're shooting antimatter so it doesn't matter if you have matter type armor?  But then again, the Borg. They have personal shields, but everyone else doesn't for some reason. Why can't Geordi or Data figure out how to create portable force fields by putting down things similar to those power poles placed in a triangular formation when they need to teleport into an "interfering" atmosphere?
122051
I've seen them maneuver. They definitely can go backwards. How fast can they go in reverse? Is warp speed possible, or is reverse limited to impulse power? If it is limited to impulse power, can they travel backwards under impulse power as fast as they travel forwards under impulse power?