This site is not maintained. Click here for the new website of Richard Dawkins.

← Is a horse a planet?

Is a horse a planet? - Comments

Richard Dawkins's Avatar Comment 1 by Richard Dawkins

A challenging question, both philosophically and scientifically. Philosophically, it goes to the heart of semantic theory. Is a planet defined as any sufficiently large object in orbit around a star? Or must it have certain appearances or properties, for example a spherical shape? If the latter, we sharply confront the scientific ramifications of this deep question. Any sufficiently large horse would instantly collapse under its own gravity and become spherical. But then it would no longer be a horse. These are deep waters indeed.

Updated: Wed, 26 May 2010 11:45:15 UTC | #473656

Quetzalcoatl's Avatar Comment 2 by Quetzalcoatl

What if the horse's bones were reinforced in some way, sufficient for it to withstand its own gravity and still maintain its shape? Or are we suggesting that the horse has to be "as evolution intended it", in order to qualify?

Wed, 26 May 2010 11:50:05 UTC | #473662

Frying Pantheist's Avatar Comment 3 by Frying Pantheist

According to the IAU definition of a planet (Wikipedia article), a planet "has sufficient mass to assume hydrostatic equilibrium (a nearly round shape)". Something that fulfilled this criterion probably wouldn't fit the definition of a "horse".

Wed, 26 May 2010 11:54:27 UTC | #473665

irate_atheist's Avatar Comment 4 by irate_atheist

Comment 1 by Richard Dawkins -

"Any sufficiently large horse would instantly collapse under its own gravity and become spherical. But then it would no longer be a horse."

But it would surely still be a horse, just a collapsed spherical one. An 'ors', perhaps.

Comment 2 by Quetzalcoatl -

"Or are we suggesting that the horse has to be "as evolution intended it", in order to qualify?"

I refer the honourable gentleman to the comment I made some moments ago.

Wed, 26 May 2010 11:55:09 UTC | #473667

souper genyus's Avatar Comment 5 by souper genyus

The International Astronomical Union's definition of a planet is as follows,

A Planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. (source)

So, it seems impossible for a horse to become a planet, mainly because of point (b). A horse that has become round due to gravitational forces would not be much of a horse at all anymore!

A horse could be a small solar system body, however.

Updated: Wed, 26 May 2010 12:01:21 UTC | #473668

Quetzalcoatl's Avatar Comment 6 by Quetzalcoatl

What if the horse were called Russell, and had a fondness for tea? Would that make any difference?

Wed, 26 May 2010 12:04:00 UTC | #473672

Tyler Durden's Avatar Comment 7 by Tyler Durden

I say neigh, a horse is not a planet, regardless of its gravitational pull; a horse is a horse, of course, unless that horse...

Wed, 26 May 2010 12:09:58 UTC | #473675

mole at the counter's Avatar Comment 8 by mole at the counter

Well, I think it would certainly orbit, but not furlong...

Wed, 26 May 2010 12:11:51 UTC | #473676

Steve Zara's Avatar Comment 9 by Steve Zara

Well, we know for a fact that the planet Golgafrincham was under threat from an enormous mutant star goat, so there is a precedent for space mammals of substantial size.

Wed, 26 May 2010 12:12:55 UTC | #473677

Oromasdes1978's Avatar Comment 10 by Oromasdes1978

What about Russell's Teapot?

Richard, I like your idea of a spherical horse - but would it still be a horse you ask? DNA tests would surely confirm that it has horse DNA would it not? So therefore although it would not conform to our requirements of what a horse should necessarily look like it would still have the required ingredients, just possibly an evolved subspecies that can survive in the vaccuum of space and withstand all the pressures put upon it. If we had this massive horse that over time and pressure would eventually become spherical, that surely would need the horse to evolve in order to adapt - we would just need an inordinate amount of space horses!

Russell's Teapot solves this problem for us as it is spherical already and any good Intelligent Teapot designer could fashion it to perform everything it needs to be in space and big enough to cope with the rigours of planetoid sized life! :D

Wed, 26 May 2010 12:19:28 UTC | #473680

chalkers's Avatar Comment 11 by chalkers

A stationary horse is a geosynchronous satellite.

Wed, 26 May 2010 12:38:58 UTC | #473688

Quetzalcoatl's Avatar Comment 12 by Quetzalcoatl

Chalkers-

I assume you meant stationary with respect to the planet's surface; the horse would of course still be in motion.

Wed, 26 May 2010 12:45:19 UTC | #473691

black wolf's Avatar Comment 13 by black wolf

In space, nobody hears you whinny.

Wed, 26 May 2010 13:02:41 UTC | #473698

black wolf's Avatar Comment 14 by black wolf

If a horse is empirically a planet, but substantially a horse, at what point exactly must its flesh be eaten, and what spell must be spoken before consumption?

Wed, 26 May 2010 13:12:41 UTC | #473704

JQisAwesome's Avatar Comment 15 by JQisAwesome

Oh, look!

Richard Dawkins, renowned evolutionary biologist, once the Professor for The Public Understanding of Science for Oxford, stops by the forum to share his years of wisdom and educate our many readers.

By discussing whether or not a horse could be a planet.

Wed, 26 May 2010 13:29:29 UTC | #473716

Quetzalcoatl's Avatar Comment 16 by Quetzalcoatl

JQisAwesome-

Yes, it's almost as if RD has a sense of humour, like most people (with notable exceptions, evidently).

Wed, 26 May 2010 13:33:57 UTC | #473719

Steve Zara's Avatar Comment 17 by Steve Zara

A fascinating comment by Richard, clearly illustrating the way that gravity tends to erase interesting features as a body gets larger. An Earth-sized horse would be only vaguely horse-like on the surface. The insides would be molten due to pressure. A larger, Jupiter-sized horse might even contain diamonds inside as the pressure compressed the carbon atoms within its body. As for whether it would form a true gas giant, that would depend on its recent meals. A Star Horse would not be horsey at all, as the temperatures of fusion would destroy all molecular structures. Some trace of the horse origin might be detectable in the spectrum. An even larger horse would collapse eventually to a Neutron Horse, with virtually no sign of mammalian origins, although a few atoms of iron from the hooves might remain on the surface. Finally, an even larger animal would collapse into a Black Horse, with no indication of what it used to be, especially not the mane and tail, because of the well-known Black Hole "No Hair" theorem: http://en.wikipedia.org/wiki/No_hair_theorem

Wed, 26 May 2010 14:08:09 UTC | #473732

Quetzalcoatl's Avatar Comment 18 by Quetzalcoatl

Personally I think Nasa should be doing more to search for signs of dark matter horses, which I think are even now cantering in graceful orbit around our galaxy. Now admittedly we may only be able to find indirect evidence for them, perhaps by looking for their gravitational effects, but I still think more should be done. I believe efforts should be put towards manufacturing dark-matter sugar cubes.

Wed, 26 May 2010 14:12:41 UTC | #473736

lehtv's Avatar Comment 19 by lehtv

So, this is the sort of intellectual discussion that was intended to replace the old forum's overrated chatter? All that development time didn't go to waste, I'm glad to see.

Btw, I could eat a horse.

Wed, 26 May 2010 14:19:07 UTC | #473739

Tyler Durden's Avatar Comment 20 by Tyler Durden

Comment 15 by JQisAwesome :

Oh, look! Richard Dawkins, renowned evolutionary biologist, once the Professor for The Public Understanding of Science for Oxford, stops by the forum to share his years of wisdom and educate our many readers.

By discussing whether or not a horse could be a planet.

Oh no! Richard Dawkins is adding comments to a thread on RichardDawkins.net - quick, someone inform the Daily Mail or AndrewBrown.

Wed, 26 May 2010 14:22:42 UTC | #473741

bendigeidfran's Avatar Comment 21 by bendigeidfran

Pluto is not a planet, but is he a dog, or just a picture of a dog?

Wed, 26 May 2010 14:50:45 UTC | #473749

Steven Mading's Avatar Comment 22 by Steven Mading

What does being nearly round in shape have to do with water? (I'm wondering where the "hydro" in "hydrostatic" comes from.)

Wed, 26 May 2010 15:05:25 UTC | #473753

Lapithes's Avatar Comment 23 by Lapithes

Wouldn't it be a dwarf planet considering it isn't spherical (or an oblate sphere)?

Wed, 26 May 2010 15:05:48 UTC | #473754

mole at the counter's Avatar Comment 24 by mole at the counter

JQ - "Atheist' / scientist has sense of humour shock". It's a disgrace I tell you... I'll alert the media...!

'JQ'? - 'Jesus Qhrist' by any chance?

Updated: Wed, 26 May 2010 15:10:43 UTC | #473755

Steven Mading's Avatar Comment 25 by Steven Mading

A Planet is a celestial body that (a) is in orbit around the Sun [...]

Shouldn't that be "a star" and not "the sun"? Otherwise the solar system would be the only place in the whole universe that can have bodies that fit the definition of "planet".

Wed, 26 May 2010 15:09:48 UTC | #473756

phodopus's Avatar Comment 26 by phodopus

What does being nearly round in shape have to do with water? (I'm wondering where the "hydro" in "hydrostatic" comes from.)

I suppose, in this case, if the forces acting on the poor horse's flesh are stronger than or as strong as the friction and binding forces within the flesh, the material can flow to a certain extend and will equalize the pressure, making its softer parts a near-static fluid in the physical sense. That would be the case for a moon sized horse for example.

Wed, 26 May 2010 15:17:48 UTC | #473761

phodopus's Avatar Comment 27 by phodopus

"Have you ever considered the existence of horses on solar orbits?"

"no, that's not my pot of tea"

Wed, 26 May 2010 15:20:02 UTC | #473762

InYourFaceNewYorker's Avatar Comment 28 by InYourFaceNewYorker

Um, am I missing something?

Wed, 26 May 2010 15:33:59 UTC | #473766

njwong's Avatar Comment 29 by njwong

Short answer: No.

If a normal sized horse is orbiting the star, I will still call it a horse, not a planet, even if the horse is orbiting the star. Thus, even if you enlarge the horse to Earth-size or Jupiter-size dimensions, the big horse will still be a horse.

Anyway, I do not understand the context for this question. I did see the "HUMOR" tag, but then, there is no such thing as a silly question, and there must have been a reason why a horse was chosen, and not some other object.

I did a Google search, but all it returned me was this lousy music video:

http://www.youtube.com/watch?v=QOgKho9ngko

:-)

Updated: Wed, 26 May 2010 15:36:30 UTC | #473767

Haymaker's Avatar Comment 30 by Haymaker

Only if cow is a moo(n)

Wed, 26 May 2010 16:00:39 UTC | #473774