# How do I place a stationary wormhole on a planets surface?

In the Commonwealth Saga by Peter F. Hamilton (and many other universes) the planets are connected by large wormholes, that stay on the surface of the planets, so you can travel through with vehicles like trains and cars.

But how are these wormholes sustained on one fixed point on the ground of the moving and spinning planets?

Wouldn't a wormhole have a certain movement vector, that couldn't cope with a spinning object?

• One may assume that this is a physics problem which Ozzie & Nigel solved when they opened the initial wormhole to Mars. – user8719 Apr 29 '13 at 13:01

It's easiest to see how a wormhole can be anchored to a planet by considering so-called "thin shell" wormholes.

The mouth of one of these is the same as its throat. [In its most symmetrical form, it would manifest as a spherical boundary between two regions of space. If you were to stick your hand through it, your hand could be thousands of light years away from your shoulder. (One assumes approximate spherical symmetry -- there's at least one hole punched through the thin matter shell through which travelers pass.)]

The matter in the wormhole's throat could be charged, in which case it could be anchored with an electric field.

If this matter is fermionic, it would obey the Pauli Exclusion Principle, and could therefore be anchored by physical constraints composed of fermionic matter -- e.g. an anchoring net.

The wormhole's throat matter, despite being negative, would still be attracted by the planet's gravity. However, the planet would be repulsed by the wormhole's matter. If it's a tiny communication wormhole (big enough for, say, a laser beam), this repulsion is insignificant. It it's a man-sized wormhole, the repulsion would exceed the attraction of any planet whose mass is less than about 1-Jupiter mass.

Despite a great deal of effort by physicists, there is currently no theoretic proof of the non-existence of wormholes. When quantum theory is considered, negative energy becomes theoretically possible. [Of course, it's also theoretically possible to reverse the rotation of the galaxy.]

It is also possible to engineer a wormhole that has arbitrarily small gravitational effects (these are called "absurdly benign" in the physics literature). Also, wormholes need not have event horizons. Although the cost of not having one is negative matter at the wormhole's throat.

Lastly, evidence is not required for rational belief in the existence of a phenomenon. Belief can be justified by a well tested theory. For example, there is no evidence for the existence of gravitational waves. But nearly all physicist believe that they exist. This was much like the widespread belief in the Higgs particle before its discovery in 2012.

Source: The Physics of Stargates -- Parallel Universes, Time Travel, and the Enigma of Wormhole Physics, by Enrico Rodrigo (2010)

• So you say, the "mouth" that is generated by the generator at the "throat's" position at the target will have a mass, that can be positioned on a planets surface? This would explain it a bit: while generating the wormhole you would only have to catch the right position of the target and if there is a gravity field at the target, then the opening there will stay at the position. But wouldn't the target wormhole opening not just fall into the inner of the planet then, consuming parts of it while it falls? – rubo77 Apr 30 '13 at 12:19
• Just had to say that now gravitational waves have been found...wormholes to be next ? ;) – Cearon O'Flynn Feb 19 '16 at 15:12

There are all sorts of problems with wormholes:

1. There is no evidence they exist.
2. Schwarzchild wormholes are surrounded by an event horizon (essentially making them look like black holes from the outside), which would completely destroy the surroundings whether or not the object was spinning
3. Traversable (Lorentzian) wormholes also have very strong distortions in spacetime with all sorts of nasty consequences for matter nearby.

So not only would they have trouble staying fixed to the ground, they'd tend to shred everything near the planet they were on (possibly including the whole planet).

Since this is not such a good plot device for most stories, one imagines that these sorts of issues are somehow circumvented. If you can do that, getting it to stick to the surface of the planet instead of orbiting around it at surface elevation (for example) doesn't seem like an insurmountable additional task.

See Wikipedia for more information, or this book (Amazon.com--text not available online AFIAK) for the mathematical physics of "real" wormholes.

• This. It's called science fiction. – evilsoup Apr 29 '13 at 16:21
• @evilsoup - People like science fiction of varying degrees of hardness. My point is that if you want it so hard that you have to worry about the angular velocity of the planet, there are other much bigger things to worry about. – Rex Kerr Apr 29 '13 at 21:44
• Are Lorentzian and Schwarzschild wormholes not the same thing, both other names for Einstein–Rosen bridges? Traversable wormholes such as the Morris–Thorne wormhole are Lorentzian/Schwarzchild/Einstein-Rosen bridges where the throat of the worm hole are held open by exotic matter? – Cearon O'Flynn Feb 19 '16 at 15:33