For example, say the Moon was slowly getting closer to the Earth instead of moving away. If this occurred slow enough, the Earth and Moon could become tidally locked, always pointing the same face to each other.

I think the opposite is actually true.

The Earth-Moon system is already evolving towards being tidally locked. The Moon is already tidally locked with the Earth. As the moon saps rotational energy from the Earth via tidal interactions, it is accelerated to a higher orbit. Eventually, the Earth will be tidally locked with the moon, at which point there will be a permanent high tide in two regions (those parts of the Earth facing directly towards and away from the moon) and a permanent low tide in other regions (those areas on Earth that face perpendicularly to a line drawn between the centres of the two bodies).

Boskone had been mined by the bad guys and blew up without any help from the Patrol.

The next baddie on the list, they took out with a “free” planet. (That is, they stuck inertia-less drives on a planet, towed it to the appropriate location, then turned off the Bergenholms restoring the original inertial velocity). I think it might have been Ploor where the Patrol dropped two of them out of inertialess drive in a maneuver they called the “Nutcracker.”

The bad guys were getting smart enough to mount massive pressor beams to ward off free planets when Kinnison formed a brain trust to invent the physics for the Nega-sphere, which was sort of a strange combination of antimatter and black hole.

Meanwhile fun with hyperspacial tubes led to the discovery of a different dimension where the speed of light was much, much, much higher. The Patrol, never shy of taking risks with the physics of our universe, stuck engines on a planet there and got it moving really, really fast…and then dropped it back into our universe as an inertial object going several times the speed of light. Einstein may have screamed a little in his grave, but basically the result was lots of energy where a planet had been. And then THAT hit the sun of the last target on their list.

It would be a poetic sight, but sadly for the poets, the force of gravity on the two objects would destroy the hourglass shape as it was forming. Eventually, they’d be one larger globe.

The BA’s post on the Icarus comet-like orbiting superjovian is here :

http://blogs.discovermagazine.com/badastronomy/2009/01/28/weather-sizzles-on-a-planet-that-kisses-its-star/

The BA’s post on Upsilon Andromedae’s weirdly orbiting world complete with excellent graphics – except that they have our own inner solar system slightly messed up (look closely near the Sun on the lower right comparison box) – is here :

http://blogs.discovermagazine.com/badastronomy/2010/05/24/nearby-planetary-system-is-seriously-screwed-up/

Toutatis wikipage is here :

http://en.wikipedia.org/wiki/Toutatis-4179

For binary asteroid Hector you’ll have to type or cut & paste from here :

624 Hektor

into the search box. Note that’s Hektor with a ‘k’ not ‘c’ – the more accurate Greek spelling.

NB. I don’t want to risk posting more than 3 links as this has caused me grief here before.

Hope this is interesting / useful for y’all so late in this thread.

Well its certainly possible for asteroids to form or be like this – Near Earth Asteroid Toutatis & jovian trojan asteroid Hector are two examples.

SF writer Robert L.Forward written an excellent novel (another of my faves & this time a very optimistic hard SF one) featuring an earthlike double planet with two lobes – a dry one named Roche (french for ‘Rock” and the Roche lobe concept discoverer) and an ocean one named Eau. (french for water.)

Some folks would argue that the Earth-Moon and Pluto-Charon systems count as double planets although they’re too distant to be in the close gravitationally distorted dumbbell configuration.

@45. Chip Says:

…Another scenario you might explore is the possibility in such a solar system of a near miss, (which doesn’t get our planetary hero off the hook for long.) What might happen is that the two planets are flung out of their solar system or at least into wildly elliptical orbits. Moving in too close and then enormously far from the binary. After surviving all the terrible earthquakes and weird weather associated with the short near-miss event, we are treated to seasons of the coldest and longest winter imaginable (frozen atmosphere) followed by the shortest but hottest summer imaginable (molten surface).

You may already know or remember that a lot of exoplanet’s found especially early on are in eccentric orbits with a few really extremely eccentric comet-like one’s being known. We think this is most likely due to planetary encounters with other more massive planets – essentially your scenario.

Eg. One of the worlds orbiting Upsilon Andromedae is highly tilted out of the plane and there was one superjovian exoplanet – HD 80606b – in an a extreme comet-like orbit that the BA described in his post on it as :

The planet’s orbit is incredibly elliptical, with a whopping eccentricity value of 0.927 — meaning the orbit is elongated like a rubber band being fought over by jealous children. It’s posited that gravitational interaction over time with a distant binary stellar companion to the star may have forced the orbit into this shape; it peaks at a distance of 125 million kilometers (75 million miles) from the star, but the planet’s 111 day orbit drops it to a mere 4 million kilometers (2.4 million miles) from the star’s surface. In the 55 days it takes to drop, it sees the disc of the star swell to 30 times its previous size, flooding the planet with nearly 800 times the amount of heat it felt at greatest distance.

Source : BA blog article 28th Jan 2009 “Weather Sizzles on aplanet that kisses its star!” {link to follow in separate comment to avoid moderation / problems. Plus links to asteroid Toutatis etc ..]

Actually I read somewhere that if Saturn was a bit more massive it could’ve started interacting with Jupiter in a way that would have caused us a lot of trouble – or menat we and Erath weouldn’t be here now!

Or short answer – yes both dumbell shaped double planets and wildly eccentric comet-like orbiting “Icarus” planets exist or probably exist.

Thoughts on whether it’s possible for such an “hourglass” planet to form?

Even more depressing – it’s starting to come true. The UK has more CCTV cameras in public places per head of population than any other country.

And they promoted them with those very Orwellian “big brother is watching” posters that were plastered all over the bus shelters and tube stations.

. . . Stephen Baxter’s Titan which would have to be *the* gloomiest (if also a fascinating and well written) SF novel I’ve ever read.

Quite possibly the most depressing SF book I have read.

(With the possible exception of George Orwell’s 1984 if you class that as SF. *That* is just the most depressing book ever. )

Even more depressing – it’s starting to come true. The UK has more CCTV cameras in public places per head of population than any other country.

This makes me so glad that Earth does not orbit a tight binary star system.

Regarding Anvil of Stars, I tend to agree with Charles Stross’s interpretation: the picture of the universe and the role of civilisations it portrays is very, very bleak indeed. Either you get wiped out or you end up as sockpuppets in a war between various factions of world-destroyers.

Yes, I see what your saying there – & I wouldn’t mind reading that Charles Stross analysis if you could point me to it, please.

However, ‘Anvil of Stars’ (AoS) is still a gripping, fascinating read and ‘Anvil of Stars’ is a lot less bleak & more optimstic than, say, Pellegrino & Zebrowski’s ‘The Killing Star’ (tKS) novel or, grimmer yet, Stephen Baxter’s Titan which would have to be *the* gloomiest (if also a fascinating and well written) SF novel I’ve ever read.

(With the possible exception of George Orwell’s 1984 if you class that as SF. *That* is just the most depressing book ever. )

‘Bleak’ doesn’t always mean bad or depressing & AoS contains some hope and is still one of my all-time favourites despite its grim outlook on the nature of ETIs.

I guess AoS along with tKS & for that matter many others offer one rather frightening explanation to the Fermi paradox which is, sadly, rather plausible.

Planetary orbits are chaotic, so a gradually evolving star could lead to a high-speed collision. But evolution of binary planetary systems and low-speed collisions might also be possible. I don’t see why those possibilities should be dismissed. I would guess that it’s the more likely outcome when each planet only has a few neighbors with which to interact. Further evolution of a clear, mature planetary system may be different from initial evolution of of a crowded disk. (And in any case, the only system we know not to contain any binary planets is our own. That doesn’t exactly prove anything.)

Second edition…

I’ll add my vote to those wishing to see a more realistic depiction of a planet’s destruction in film. The breakup of Alderon didn’t make it; it happened much too fast.

Dim memory number 2: Somewhere in one of E. E. “Doc” Smith’s Lensman novels there’s a scene where the good guys wipe out a planet full of chronically bad guys by setting up some sort of massively dense force field in its path. My recollection is that this collision is described somewhat accurately. But of course it’s in print, not on film.

Cool! In the second novel, they find that the planet they escape to had been inhabited by an intelligent race. I dimly remember some sort of monument with an inscription that a scientist manages to partly translate. Evidently it’s about the coming doom; he calls it “Talon.”

Your question is nearly impossible to answer at our current level of mathematical understanding,ie, we’re unable to EXACTLY calculate interactions between more than 3 ideal bodies(bodies that are exactly equal in mass and relative positions). It’s called the three body problem.

Now, if we use a really BIG computer, we can approximate the answer, but that will take a while, since we have to calculate the positions of each object, then the effect one has on two, then two on three, then three on one and two, then,,,well, you get the picture. Which is why our space craft have to be able to correct their trajectories in flight, to correct for exactly where they are vs where the planet/asteroid/comet is going to be(w/in margins of error).

It may be easy to hit the moon, but a fast moving asteroid/etc is another matter.

Gary 7