[Aachen]

Exoplanets also aren't planets. Some things just seem to have definitions with a history that get applied to new discoveries that don't fall within the definition. Distinguishing random rocks in space from planets was done by requiring planets to orbit around the sun, and so planets elsewhere cannot be called planets no matter that it's 1:1 the same thing. Biology probably has a similar history of trying to draw a line somewhere between what was created and what evolved to be part of the 'natural' world

[oliverx0]

Exoplanets are planets. Also, for clarification, biology is not defined as “the study of things produced exclusively by natural evolution.” Synthetic biology works with biological components and living systems (DNA, proteins, regulatory networks, cells and organisms). It differs from much traditional biology mainly in its constructive, engineering-oriented approach. Synthetic systems are often built precisely to test hypotheses about how natural biological systems function. Claiming it is not biology is wrong IMO.

[cookingmyserver]

For anyone else that might be curios, the definition of a planet you will often see quoted online applies to bodies in our Solar System. It comes from the International Astronomical Union in 2006. This is the famous definition that dropped Pluto as a planet. While the criteria are widely quoted, that actual resolution isn't. The resolution:

The IAU...resolves that planets and other bodies, except satellites, in the Solar System be defined into three distinct categories in the following way:

(1) A planet [1] 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.

(2) A "dwarf 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 [2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects [3], except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

The definition here only applies to bodies in the Solar System.

Still a bad definition IMO. According to the definition if a catastrophic event were to occur that cluttered the neighborhood of a planet it would cease to be a planet until it was cleaned up. The definition of a planet should be based in the physical attributes of the celestial body itself, not in its role or relationship with other bodies. I'm a bit of an extremist on this front. Even our Moon would be a planet in my opinion. Seems silly when you think about our barren moon but there are for sure habitable moons out there. I can't imagine asking an alien "What planet are you from?" and them responding "erm, actually we are from a moon/planetary satellite".

[hparadiz]

> Captain's Log, Stardate 1513.1. Our position, orbiting planet M-113. On board the Enterprise, Mr. Spock, temporarily in command.

<<insert nerd screeching about the word planet>>

[paulddraper]

Eh, that doesn't make sense.

What's a meteor?

[cookingmyserver]

The streak of light generated by a small astronomical body as it moves through the atmosphere of earth (or another astronomical body).

[paulddraper]

Meteoroid then.

Asteroids and meteoroids are the same, except for where they are positions.

Mothers and women are the same, except for their relationships to others.

[cookingmyserver]

And notice how we have those two different words - mother and woman? You can have words that describe relationships, in fact that is really good! You can even compound words or create whole new ones to encompass multiple types of attributes! What we should avoid is taking widely used words and changing the definition to add a criterion that is of a whole other type of attribute.

Your mother and woman example is perfect! It would not be appropriate to most people to change the definition of woman to a female that had or has an offspring. You are taking a definition that describes an attribute of the subject (gender) and throwing in criteria that is based on a relationship. That makes no sense!

If it is important for you to make a distinction on whether an astronomical body has cleared its neighborhood then you can create a new word or compound word.

[ferfumarma]

Right? It's biology when you study enzymes in vitro, but as soon as you put a membrane around them then it's ... something else?

Bizarre argument.

[jibal]

> Exoplanets also aren't planets.

That is flatly wrong.

https://en.wikipedia.org/wiki/Exoplanet

"An exoplanet or extrasolar planet is a planet outside the Solar System."

[MarkusQ]

The GP post's point was that, logical as this would be, the IAU definition explicitly states that planets are "in the Solar System". So no, exoplanets are exoplanets, not planets. And Pluto isn't an example of either.

[jibal]

No, The IAU definition does not say that. You and others are confusing the definition of a planet with its application to planets in the solar system (and thus to Pluto) -- IAU Resolution 5A: Definition of a Planet in the Solar System.

The IAU of course does not assert that only planets in the solar system are planets ... that would be ridiculous, and the interpretation of the IAU's stance as being so ridiculous is ridiculous and then some.

https://science.nasa.gov/solar-system/planets/what-is-a-plan...

"The definition of a planet adopted by the IAU says a planet must do three things:

It must orbit a star (in our cosmic neighborhood, the Sun).

It must be big enough to have enough gravity to force it into a spherical shape.

It must be big enough that its gravity has cleared away any other objects of a similar size near its orbit around the Sun."

https://www.iau.org/IAU/Science/What-we-do/Pluto-and-the-Dev...

"More generally, a planet:

a. orbits its host star, just as the Earth and Jupiter orbit the Sun,

b. is large enough to be mostly round, and

c. must have an important influence on the orbital stability of the other objects in its neighbourhood."

[hparadiz]

> Exoplanets also aren't planets.

Imagine writing this.

[LeifCarrotson]

What they meant when they said "planets" was the 8 (previously 9, previously to that 8, previously 7...) known and named planets in our own solar system. A hypothetical "Journal of Planets" that was actually about solar system astronomy wouldn't necessarily have known what to do with a new paper about 51 Pegasi b published 30 years ago. They're thinking "when we said planets, we actually always meant solar system planets, it just never came up until now".

The reviewer of this paper is saying that by biology they always meant naturally evolved cellular biology, not synthetic biology - there's just never been an example of the latter before.

I think the take is wrong, the receiving journals should be excited to expand their scope rather than frustratedly redefine their scope more narrowly, but definitions and categorization are hard.

[jibal]

> What they meant when they said "planets"

Who is "they", and how do you know what they meant?

The relevant fact is that the claim "Exoplanets also aren't planets" is simply wrong -- exoplanets are by definition planets outside the solar system. It's like claiming that a brown furple isn't a furple -- the claim is wrong, regardless of what one thinks a furple is.

> The reviewer of this paper is saying that by biology they always meant naturally evolved cellular biology, not synthetic biology - there's just never been an example of the latter before.

They aren't saying that, and that isn't true.

[ben_w]

> exoplanets are by definition planets outside the solar system. It's like claiming that a brown furple isn't a furple -- the claim is wrong, regardless of what one thinks a furple is.

If only language was so logical.

While I happen to agree that exoplanets are planets, as with my point in the other comment, I aver the stronger claim ("regardless") does not follow in this context.

Stonehenge, after which the concept of a henge is named, does not meet the current archeological definition of a henge: https://en.wikipedia.org/wiki/Henge

Jerusalem artichokes are neither artichokes nor from Jerusalem: https://en.wikipedia.org/wiki/Jerusalem_artichoke

Guinea pigs are not pigs and are not from Guinea: https://en.wikipedia.org/wiki/Guinea_pig

The "mincemeat" in a mince pie is, these days, usually vegetarian: https://en.wikipedia.org/wiki/Mincemeat

Chinese checkers is German and plays nothing like checkers. Peanuts are not nuts, strawberries are not berries, hamburgers do not generally contain ham, a killer whale is actually a dolphin, etc.

[jibal]

I don't need an off topic point-missing lecture on how language works that could have and might as well have been written by a clanker. The fact remains that exoplanets are by definition a type of planet, regardless of whether Jerusalem artichokes are a type of artichoke -- proper names as adjectives work differently, and the "mincemeat" example is simply bad faith ... actually, the whole pushback here is bad faith argumentation.

And "gas giants are failed stars and shouldn't count as planets" is completely irrelevant -- at best it's a fallacy of denial of the antecedent.

I won't respond further.

[antonvs]

The argument you describe is as if Neil deGrasse Tyson took a course about “How to be even more extremely and inappropriately pedantic,” and decided he wanted to become the undisputed world expert at that.

Anyone who says “exoplanets aren’t planets” really needs to think a little harder about the actual meaning of what they’re saying.

[Aerolfos]

Actually, that is the IAU stance. And their definition for exoplanet includes small, non-rounded objects orbiting stars which would be asteroids (or comets or whatever) if they happened to be around the Sun.

All that debacle around dwarf planets to prepare for future observations, and yet the distinction ceases to apply the moment you go outside the Oort cloud...

But really, that's just the naming systems being bad, obviously common people don't think asteroids around other stars are "exoplanets" or should be called that way

[jibal]

This is quite wrong.

https://www.iau.org/IAU/Science/What-we-do/Pluto-and-the-Dev...

"More generally, a planet:

a. orbits its host star, just as the Earth and Jupiter orbit the Sun,

b. is large enough to be mostly round, and

c. must have an important influence on the orbital stability of the other objects in its neighbourhood."

Exoplanets are planets by that definition where the host star is not our Sun:

"Researchers have found hundreds of extrasolar planets, or exoplanets, that reside outside our solar system. "

[hparadiz]

I'm not talking about edge cases like asteroids or planetoids or dwarf planets. I'm talking about actual planets. Like a gas giant orbiting a star. It's obviously a planet even if it's not orbiting Sol.

[ben_w]

It's perfectly coherent to argue that gas giants should count failed stars rather than as planets, given the boundary between them is under debate.

https://en.wikipedia.org/wiki/WISE_0855%E2%88%920714

[jibal]

It's perfectly irrelevant to the thread.

[ben_w]

This thread is ~

  "Exoplanets also aren't planets": discuss

As the easiest to discover exoplanets (and all the early ones except pulsar planets) are gas giants, and the comment I was directly replying to had "Like a gas giant orbiting a star. It's obviously a planet", therefore "gas giants are failed stars and shouldn't count as planets" is not at all irrelevant.

Even further up to the point of if these are or are not cell, it illustrates how taxonomical categories are made by humans for humans. Historically, any connection to natural laws in taxonomies is often mere coincidence.