17
votes
Accepted
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
Faraday cage
Your microwave oven has one, to prevent the radiation getting out. If you put your cell phone in one and try to dial it, it can't be reached.
You can, if you wish, make it feel like they ...
- 27.1k
15
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
Frame Challenge
Why make it a Physics problem? In order to open a Portal from current location to known locations, the Protagonist has to know where they are. Not down to an exact GPS co-ordinate, but ...
- 15.9k
14
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
Air pressure
(As I reread your post after writing this, I only now realize this is probably what you meant by "vacuum related".)
If you were to open a portal from one location to another ...
- 1,027
8
votes
Accepted
Amount of antimatter needed to propel large spacecraft?
I don't think you can mark a answer to be correct if it uses classical mechanics, but whatever. $\frac{1}{2}mv^2$ definitely does not work at these speeds anymore, plus there is a factor missing.
...
- 1,022
8
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
Opening a wormhole portal is not possible with science as we know it here and now. So you need some science-fictional "McGuffin" to do that, and you are free to introduce restrictions on it. ...
- 110k
6
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
A certain amount of kinetic energy is required
This is a real phenomenon that might exist for a subset of thin shell spherically symmetric wormholes.
Consider the diagram (source from link):
An ...
- 5,867
5
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
Make portals give off sparks
Since portals slice atoms in half, they cause fission of local materials, which tends to cause sparks and heat generation. The labs have some sort of knockout gas to ...
- 37.3k
5
votes
Accepted
Communication between a stationary observer and a spaceship traveling at near lightspeed
Bob and Alice start in the same place with synchronized clocks. Alice is flying away from Bob towards Planet X at $v=.9998c$. Assign Alice time $\tau$, assign Bob time $t$. Bob sends a message to ...
- 2,732
5
votes
Communication between a stationary observer and a spaceship traveling at near lightspeed
They can send signal and they will not receive them at the same time. Light speed is always c no matter the relative motion.
What they will observe is relativistic Doppler effect:
The relativistic ...
- 272k
4
votes
Would direct matter to energy conversion be hazardous?
It depends on how its done, and how much is converted.
Energy can have many forms, when we do matter energy conversion, we usually get heat and radiation as the energy, which certainly can be ...
- 13.7k
4
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
Although I like the already posted Faraday cage solution the most, if you need something active, something that can later be disabled or deactivated, then just use a strong electromagnetic ...
- 11.2k
3
votes
Amount of antimatter needed to propel large spacecraft?
Two problems:
250 tons of cargo, not 250 tons of ship. I'd be more inclined to believe 1000 tons of ship including cargo.
Somehow, your calculations were wrong... I got 61,250 kg of matter from ...
- 52.3k
3
votes
Could a planetary object spin at (or near )the speed of light?
No.
If an object was to be spun at an angular velocity such that its surface even approached the speed of light, centrifugal forces would tear apart any object made from real matter, and anything on ...
- 52.3k
3
votes
How long would it take for a Japanese-style castle to burn to the ground?
My Answer: Probably over a period of 1-2 hours.
According to Goggling - Cypress Wood is the wood of choice for Japanese Castles, this is it's Firewood properties
The first thing is that compared to ...
- 15.9k
3
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
Establish requirements, then break them
One way to limit a character's ability to open portal is to establish some kind of requirement from the character's point of view for portals to be opened, then ...
- 1,027
2
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
How about good(?), old, very much non-physics coercion?
"That's a nice portal you've got there. Feel free to use it. But if you do, you'll never know what happened to your beloved, whom right ...
- 519
2
votes
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
When people think of physics labs, they often picture lasers, antimatter containment and miniature particle accelerators.
When I think of physics labs, I think of high school physics and how my family ...
- 134k
2
votes
Would direct matter to energy conversion be hazardous?
If they have the technological acumen to do something impossible they probably can deal with minor problem of radiation.
You are asking if your imaginary impossible technology has specific physical ...
- 2,281
2
votes
Accepted
Would direct matter to energy conversion be hazardous?
Direct matter to energy conversion, according to our physics, produces gamma radiation, which in itself is surely hazardous.
When the radiation interacts with matter it generates other potentially ...
- 272k
1
vote
How long would it take for a Japanese-style castle to burn to the ground?
Japanese weren't stupid, they coated their Castles in fire retardant/resistant plaster and mud. So while you can get a local fire going, it's not going to spread easily.
Your arsonist needs to set ...
- 22.2k
1
vote
Could a planetary object spin at (or near )the speed of light?
No, nothing can move at the speed of light except light as far as we know.
Nothing physical could survive spinning anywhere near the speed of light without being destroyed.
- 22.2k
1
vote
How should I determine the properties of keels and ether?
The formula for speed would likely match the one used in normal sails
See, you have here two forces that make your flying sailship move: the force of wind hitting the sails (and body, as it would ...
- 5,177
1
vote
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
The portal is inside a number of shell like spheres, which are rotating very fast. The centrifugal force, which the researchers are subject to equals to a g- always away from the portal. Anything ...
- 1,100
1
vote
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
In the Long Earth and Merchant Princes series, humans can "jump" from world to world. However, those jumps can only take place at the same altitude. One can build "escape proof" ...
- 1,647
1
vote
What type of security measure/contingent conditions could make jumping into a portal impossible inside a laboratory?
The portals created by the MC are set to close automatically after a set amount of material (a bit over the MC's mass plus a safety margin) passes through them in order to avoid having to close each ...
- 2,826
Only top scored, non community-wiki answers of a minimum length are eligible