Interview with creator of Universe Sandbox at 4pm PST

[smjjames]

For antimatter, theres the photon torpedo when you press Y, not sure if that counts, it does explode things on contact though.

Having something like your example with the space time distortion depending on mass would be cool. One problem though as far as relativity goes is that there is no 'speed limit' in US and you can accidentially make objects fly at FTL speeds if the time step is too high and in order to have a stable orbit close to a black hole (within it's Event Horizon), you have to, and can make things go FTL.

Speaking of the Event Horizon, maybe we can have an event horizon indicator for black holes? Escape velocity is already calculated among other stuff, so it shouldn't be too hard.

[Bogdan45]

Well,just as the example shows, if we go faster than the speed of light, we could go back in time
As the object aproaches the speed of light, the time slows down until, at the speed of light will get to be zero and the space gets compressed (for us the observers, which is exactly what we are in US. We another ideea would be to simulate the perspective of being ON the object that travels faster than SOL).
(it shouldn't be hard to simulate, we keep going faster in space while the time goes negative.)

That would interesting to explore

[smjjames]

Only thing though, it's the object, not the observer (well okay, if the observer were ON said FTL object....) that is going FTL and the sim involves multiple bodies, how is Dan going to handle that? We can't rewind (go backwards in time that is), so we would need such a feature first maybe.

Speaking of FTL speeds and compression and all that, I wonder how the improved collision Dan mentioned will handle that, given the incredible amount of energy involved.....

[Bogdan45]

how is Dan going to handle that?

Well, for the perspective from the body traveling faster than SOL, the simulation would slow down as we approach the SOL. Now while the time would go forward and the speed would increase beyond SOL, the simulation would increasingly go backwards

In regards to the other perspective, normal US watching an object go faster than SOL, we would see the object compress until the point of no return (>= SOL) where the object would dissapear  since now it would go back in time.
I think 

[Bogdan45]

Also the Event Horizon effect would awesome.
We could see the object "spaghettify" LOL.

http://en.wikipedia.org/wiki/Spaghettification

Do we dare think about wormholes (think Farscape)...
 

[smjjames]

Okay, but go back in time to where, or rather when? While I understand what you are saying, I'm not sure how Dan is going to implement the whole thing, given that we can't reverse the flow of time in the simulator, yet.

As for a wormhole, to my understanding, a wormhole either requires a singularity, or some sort of negative density material or other exotic material to keep it open, or both.

In it's simplest terms as far as programming goes, a wormhole can be treated as a portal, but this is a physics simulation sandbox.

[Bogdan45]

Okay, but go back in time to where, or rather when?

I believe the object should go forward in space, continuing its original trajectory, while the time would go negative.
(when the engine would have the capability implemented). Also, important, the space would look warped from the perspective on the object.
Come on guys, does anybody watches Brian Green?

Yes wormholes require a massive black hole to rip space time and bridge it somewhere else. Yes, a portal is good analogy but where it would end up, well could set up restrictions for example to immediate space.

Here is a simulation of relativistic path using open physics simulator (Java):
http://www.compadre.org/precollege/items/detail.cfm?ID=7351

[Bogdan45]

I forgot something important, going faster than SOL would increase the objects mass (and we would assume that the object has an unlimited source of energy  ). That implies that as the objects mass increases it may as well turn into a black hole.

[Bogdan45]

Another issue, to have US behave as closely as possible to the real observed universe, is to take in consideration that the space is expanding. US can simulate wast time periods during which the space expands with a certain factor.

Also, forgot about this too, Doppler Shift!!!
Here is a demo about that using a software simulation made in Australia:

http://www.anu.edu.au/Physics/Savage/TEE/site/tee/solar_system/earth_big.html

[Bogdan45]

Here is an animation of space expansion:

[vh]

wormholes would be interesting. can't imagine how they would work.

Also, Bogdan45, it helps to use the modify button instead of making a new post

[Darvince]

Wormholes would most likely work like this:
The object encounters the wormhole's surface, then its position is moved to right next to the destination wormholes of that one.

[vh]

so a wormhole when you clicked "add" would come in two pieces you could seperately manipulate.
or maybe select two objects and click "wormhole" like there is a "black hole" button.

[Bogdan45]

Well, we could start with a regular star that we know its age and mass. After a certain time we know that certain mass stars will implode creating a supernova that might form either a neutron star or a black hole depending on the star initial mass. Now, having a black hole we could "feed it" stars (and the process could look spectacular) until the black hole becomes so massive that it would rip the space-time creating a wormhole. Now some examples:

General info on Black Holes on Wiki:
http://en.wikipedia.org/wiki/Black_hole

A Black Hole
http://en.wikipedia.org/wiki/File:BH_LMC.png

Supermassive Black Holes (good simulations):
The Largest Black Holes in the Universe

How gravitational lensing should look:
http://en.wikipedia.org/wiki/File:Black_hole_lensing_web.gif

How a Supernova could look:
Supernova Explosion Simulation
Super Nova Shock Wave
Realistic Supernova simulation (must see  ):
Supernova _ the most realistic computer simulation untill now

[vh]

it'd be nice to be able to place wormholes instead of doing some process.
Also stars do not age in universe sandbox.

[smjjames]

We can't make a proper supernova just yet with US, about all we can do is take a star and explode it into as many pieces as your computer can handle, along with generating a LOT of dust particles. The improved collision (and possibly explosion) dynamics that Dan talked about could be a step in this direction though.

Theres at least two US videos of star exploding that looked good and were maybe non spherical, but I'm not sure how to do it that way and it may have been the 2009 version.

@mudkipz: Could be a potential feature in a future release though.

[vh]

can i see the videos?

[Darvince]

Well isn't negative mass near the same thing as antimatter?

[Bla]

Well isn't negative mass near the same thing as antimatter?

Antimatter annihilates normal matter on contact, turning the matter and antimatter into energy. It's still affected by gravity.

[deoxy99]

Bla, can you cut the discussion out? The discussion of antimatter and such doesn't seem to go here, this is about the interview, not about features (even if the interview was discussing new features).

[atomic7732]

Antimatter annihilates normal matter on contact

This would imply that the antimatter still exists. I prefer to say they annihilate each other.

[smjjames]

can i see the videos?

I don't remember where they are and they might have been yours, but I'll see if I can find them again.

Edit: http://universesandbox.com/forum/index.php/topic,1746.msg17070.html#msg17070 I guess this is what I was thinking about and there is only one video. It's something with dust though and not explosion, which I somehow thought it was. I don't even know how to create those patterns that ChaoticCow posted in that thread.

[Bla]

Antimatter annihilates normal matter on contact

This would imply that the antimatter still exists. I prefer to say they annihilate each other.

True, they annihilate each other. I would also prefer to say that, when I remember it. But I think this is really just quibbling.

Deoxy, I think it's okay to have broad discussions in a topic, and we can always continue to split topics into smaller and smaller bits (like the new antimatter topic into one discussing it as a feature and another discussing it scientifically). I think I'll leave it up to Dan to split it if he wants it. I can't remember if antimatter was a discussed feature in the interview, but I think it would be very relevant to discuss it in this topic if it were. Otherwise I agree with you.

[FiahOwl]

Antimatter annihilates normal matter on contact

This would imply that the antimatter still exists. I prefer to say they annihilate each other.

True, they annihilate each other. I would also prefer to say that, when I remember it. But I think this is really just quibbling.

Deoxy, I think it's okay to have broad discussions in a topic, and we can always continue to split topics into smaller and smaller bits (like the new antimatter topic into one discussing it as a feature and another discussing it scientifically). I think I'll leave it up to Dan to split it if he wants it. I can't remember if antimatter was a discussed feature in the interview, but I think it would be very relevant to discuss it in this topic if it were. Otherwise I agree with you.

They did discuss a few on Dark matter.

[deoxy99]

Fiah, that's dark matter, not anti-matter.

[FiahOwl]

Fiah, that's dark matter, not anti-matter.

Very similar things.

[deoxy99]

No... here's one difference: we don't know what dark matter is, we do know what anti-matter is.

Another: Anti-matter annihilates matter. Dark matter does not, it instead fills the space of the universe, if it did annihilate matter, this universe wouldn't exist right now, or it'd be a void.

Another: There isn't that much antimatter, but there sure is a ton of dark matter.

ANOTHER: Antimatter is essentially the opposite of matter. Dark matter isn't the opposite of matter, it's a new type of matter.

Why do people think that dark matter and antimatter are the same? They aren't... at all.

[FiahOwl]

No... here's one difference: we don't know what dark matter is, we do know what anti-matter is.

Another: Anti-matter annihilates matter. Dark matter does not, it instead fills the space of the universe, if it did annihilate matter, this universe wouldn't exist right now, or it'd be a void.

Another: There isn't that much antimatter, but there sure is a ton of dark matter.

ANOTHER: Antimatter is essentially the opposite of matter. Dark matter isn't the opposite of matter, it's a new type of matter.

Why do people think that dark matter and antimatter are the same? They aren't... at all.

MASSIVE BRAIN FART!!!

[Bogdan45]

Anti-matter is the opposite of matter and is being described by the supersymmetry theory that postulates that every atomic particle has a coresponding anti-particle. Thus an electron (which is negatively charged) has a positron (positively charged). When they encounter each other they annihiliate each other creating pure energy.

Dark matter is stuff that makes up ~85% of the Universe (but 0% of the Universe Sandbox  ). It got discovered only by the effect it has on rotation of galaxies. U guys didn't watch those videos I've posted.