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2514 clicks; posted to Geek » on 14 Mar 2019 at 4:07 PM (6 days ago)   |   Favorite    |   share:    more»

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That actually makes perfect sense to a layperson, and I am surprised this is not how we calculated how close planets are to each other.

Is Neil deGrasse Tyson farking everything up again?

The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

and that their orbits weren't at an angle relative to one another.

Which they aren't.  Planetary orbits are coplanar, except for the Pluto formerly known as a planet.  While this is a nifty bit of mathematical ingenutity, I'd like to see them run the experiment with the actual orbits.

Math isn't real.  How does this work with the actual planets?

I think we should determine proximity based on the delta-V needed to send 1 kg to the planet.

Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

and that their orbits weren't at an angle relative to one another.

Which they aren't.  Planetary orbits are coplanar, except for the Pluto formerly known as a planet.  While this is a nifty bit of mathematical ingenutity, I'd like to see them run the experiment with the actual orbits.

Neither of which has anything to do with calculating that Mercury is closest to Earth.
// confirming why I have you flagged as ignorant blowhard

The helical model - our solar system is a vortex

Wonder how THIS model would impact the calculations

Well, sometimes.

The thing about planets is they are not fixed and static. They move. They lap each other. Sometimes they are on opposite sides of the Sun. It is the orbits that are more or less fixed with respect to each other, not the planets. And even the orbits wobble.

As seen from the Earth, the orbit of Venus is a beautfiul rose window, very appropriate to the Goddess of Love.

The orbit of Mercury looks more like a bicycle tire, very appropriate to the Messenger of the Gods. If you want to explore the matter further, get yourself an old-timey Spirograph and work out the orbits yourself with pen and ink on paper.

This is all just semantics based on how you want to define 'closest'. Do you go by the orbit or by the planet's specific position. Because yes, Venus is the closest ORBIT to Earth's orbit, even if the distance from planet to planet is shorter on average for Mercury.

Wonder how THIS model would impact the calculations

Besides being totally wrong?

Benevolent Misanthrope: Planetary orbits are coplanar, except for the Pluto formerly known as a planet.

If you drop Pluto from the list, Mercury is no longer coplanar. It's 3x the inclination from the invariable plane as the next-most planet.

PirateKing: Besides being totally wrong?

It CAN'T be wrong - the internet said so!
(what do I know - I thought it looked cool but I ain't no rocket surgeon)

HairBolus: Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

and that their orbits weren't at an angle relative to one another.

Which they aren't.  Planetary orbits are coplanar, except for the Pluto formerly known as a planet.  While this is a nifty bit of mathematical ingenutity, I'd like to see them run the experiment with the actual orbits.

Neither of which has anything to do with calculating that Mercury is closest to Earth.
// confirming why I have you flagged as ignorant blowhard

LOL - you wound me sir.  I don't know what I shall do with myself, knowing you don't like me.

Benevolent Misanthrope: HairBolus: Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

and that their orbits weren't at an angle relative to one another.

Which they aren't.  Planetary orbits are coplanar, except for the Pluto formerly known as a planet.  While this is a nifty bit of mathematical ingenutity, I'd like to see them run the experiment with the actual orbits.

Neither of which has anything to do with calculating that Mercury is closest to Earth.
// confirming why I have you flagged as ignorant blowhard

LOL - you wound me sir.  I don't know what I shall do with myself, knowing you don't like me.

You could take some classes. Because he or she is correct about you being wrong.

I would guess that for any given (single-star) solar system, it is likely that the planet closest to the host star would be (on average) the closest to the other planets.

A planet's average distance to its star is not going to vary as much as its average distance to any other planets, so the planet closest to the star will see the least variation.

Of course, this wouldn't always be the case. I can imagine exceptions where two planets remain in similar orbits for long periods of time.

PirateKing: This is all just semantics based on how you want to define 'closest'. Do you go by the orbit or by the planet's specific position. Because yes, Venus is the closest ORBIT to Earth's orbit, even if the distance from planet to planet is shorter on average for Mercury.

I wouldn't call it semantics. "Closest," in the way this article uses it, is exactly what anyone and everyone would assume "closest" is. It is the shortest linear distance between two points.

"Venus is on average 1.14 AU from Earth, but Mercury is a much closer 1.04 AU."
So Mercury is on average the closest planet.
The Sun is even closer, at 1.0 AU.

Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

Ellipses are approximate circles.

Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

and that their orbits weren't at an angle relative to one another.

Which they aren't.  Planetary orbits are coplanar, except for the Pluto formerly known as a planet.  While this is a nifty bit of mathematical ingenutity, I'd like to see them run the experiment with the actual orbits.

Abstracting the orbits of the planets from Neptune inwards as coplanar circles won't change the results. The planets are coplanar (within a small difference), and their orbits are very close to circles.

The differences between the real orbits eccentricity and inclination and this abstraction are minimal.

I think the most fun takeaway here is that Mercury is closest by average to ALL THE OTHER PLANETS TOO.

It CAN'T be wrong - the internet said so!
(what do I know - I thought it looked cool but I ain't no rocket surgeon)

I mean, it's useful as it does get you thinking about systems larger than the one solar system.

The problem is that our solar system does not move that way through the galaxy.

JohnBigBootay: Benevolent Misanthrope: HairBolus: Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

and that their orbits weren't at an angle relative to one another.

Which they aren't.  Planetary orbits are coplanar, except for the Pluto formerly known as a planet.  While this is a nifty bit of mathematical ingenutity, I'd like to see them run the experiment with the actual orbits.

Neither of which has anything to do with calculating that Mercury is closest to Earth.
// confirming why I have you flagged as ignorant blowhard

LOL - you wound me sir.  I don't know what I shall do with myself, knowing you don't like me.

You could take some classes. Because he or she is correct about you being wrong.

I freely admit that I mistook the relevance of having one assumption of the simulation be factually incorrect.  Taking classes won't make Mr "ignorant blowhard" like me, though.

Wonder how THIS model would impact the calculations

That "model" has the planets dragged behind the Sun as it travels through the Galaxy which is dead wrong to put it mildly.  I imagine changing were the planets are would change the calculation.   Of course I doubt that the video maker ever bothered to give an equations defining where the planets actual in his "model."

The moon may be smaller than the Earth, but it's farther away.

I'm telling you, I'm telling you so you know, it's turtles all the way down. ALL THE WAY.

HairBolus: Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

and that their orbits weren't at an angle relative to one another.

Which they aren't.  Planetary orbits are coplanar, except for the Pluto formerly known as a planet.  While this is a nifty bit of mathematical ingenutity, I'd like to see them run the experiment with the actual orbits.

Neither of which has anything to do with calculating that Mercury is closest to Earth.
// confirming why I have you flagged as ignorant blowhard

======================================​=========

They most certainly do affect the calculation.  But it's so small of a difference it's effectively meaningless.

Marcus Aurelius: The moon may be smaller than the Earth, but it's farther away.

Oh, bullshiat.

I heard this several weeks ago on a BBC Podcast (Behind the Stats, if memory serves*). How did somebody get a published paper out of it?

*It so rarely does these days, I really need to stop using that expression

Everyone who understood anything about the solar system already knew that. Besides that it's irrelevant. The planet ever to come closest to Earth is still Venus. Talking about average distance will get you nowhere. Of course the most central body will be the closest to everything else on average. But that means nothing and proves nothing, you only just got a basic lesson of geometry and what orbital movement means.

Venus and Mars are alright tonight.

The only planetary distances I'm interested in are delta-v and transit time to reach. By both of those measures Venus is closer.

I don't think they really needed a mathematical model to prove what they're saying here, if you calculate average distance across a hundred year period, it's pretty obvious everything is closer to the Sun then they are to planets transit opposite the Sun, on average.

Are these planets going to collide?

theguyyousaw: Are these planets going to collide?

Eventually, yes.
After they've been swallowed by the Sun.

doglover: Math isn't real.  How does this work with the actual planets?

If you're going to take the time to run simulations why simplify the orbits? You can get pretty good equations for the orbits of every planet, including Pluto, and then find out their average distances from one another. It's the kind of thing you rig up in Excel when you're bored.

Soulless Carbon Rod: Everyone who understood anything about the solar system already knew that. Besides that it's irrelevant. The planet ever to come closest to Earth is still Venus. Talking about average distance will get you nowhere. Of course the most central body will be the closest to everything else on average. But that means nothing and proves nothing, you only just got a basic lesson of geometry and what orbital movement means.

It sounds like they were trying to state something that was already known in a way that would sound like it meant something else to get themselves published and people talking about it and them. I'm not really sure what that's going to accomplish except getting a lot of people to think Mercury is closer to the Earth than Venus because they read it somewhere on the internet and now can't remember why.

Diogenes: Is Neil deGrasse Tyson farking everything up again?

Nah. Mike Brown again. Turns out, Earth isn't a planet either. You'll get over it.

emtwo: PirateKing: This is all just semantics based on how you want to define 'closest'. Do you go by the orbit or by the planet's specific position. Because yes, Venus is the closest ORBIT to Earth's orbit, even if the distance from planet to planet is shorter on average for Mercury.

I wouldn't call it semantics. "Closest," in the way this article uses it, is exactly what anyone and everyone would assume "closest" is. It is the shortest linear distance between two points.

No, it's not the way "anyone and everyone would assume 'closest' is."

Which circle (orbit) is the closest to black? Red or blue? Ask 1000 people and 1000 will say blue. Not a one would say red. In this diagram, red would be Mercury, blue would be Venus, and black would be Earth.

Alien Robot: emtwo: PirateKing: This is all just semantics based on how you want to define 'closest'. Do you go by the orbit or by the planet's specific position. Because yes, Venus is the closest ORBIT to Earth's orbit, even if the distance from planet to planet is shorter on average for Mercury.

I wouldn't call it semantics. "Closest," in the way this article uses it, is exactly what anyone and everyone would assume "closest" is. It is the shortest linear distance between two points.

No, it's not the way "anyone and everyone would assume 'closest' is."

[img.fark.net image 850x478]

Which circle (orbit) is the closest to black? Red or blue? Ask 1000 people and 1000 will say blue. Not a one would say red. In this diagram, red would be Mercury, blue would be Venus, and black would be Earth.

They're talking about planets. Objects. The shortest distance between them.

Orbital paths are not objects. If you wanted to find the shortest distance between two orbital paths, your model would be correct.

In this case, they are talking about planets.

Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

Earth's elliptical isn't "approximately circular"?  Are you sure about that?

Earth's perihelion is 91.4 million miles while aphelion is 94.5 million miles.  Using the actual orbit versus the circular average would make very little difference in these calculations.

emtwo: PirateKing: This is all just semantics based on how you want to define 'closest'. Do you go by the orbit or by the planet's specific position. Because yes, Venus is the closest ORBIT to Earth's orbit, even if the distance from planet to planet is shorter on average for Mercury.

I wouldn't call it semantics. "Closest," in the way this article uses it, is exactly what anyone and everyone would assume "closest" is. It is the shortest linear distance between two points.

Not really.  Currently we are closest to Mercury.  On average, we are closer to Mercury. But on March 25, 2017, we were closer to Venus than we will ever be to Mercury.

https://in-the-sky.org/solarsystem.php​<---- fun widget!

RabidRythmDivas: Benevolent Misanthrope: The researchers ran a simulation based on two assumptions: that the planets' orbits were approximately circular,

which they are not, being elliptical,

Earth's elliptical isn't "approximately circular"?  Are you sure about that?

Earth's perihelion is 91.4 million miles while aphelion is 94.5 million miles.  Using the actual orbit versus the circular average would make very little difference in these calculations.

emtwo: Alien Robot: emtwo: PirateKing: This is all just semantics based on how you want to define 'closest'. Do you go by the orbit or by the planet's specific position. Because yes, Venus is the closest ORBIT to Earth's orbit, even if the distance from planet to planet is shorter on average for Mercury.

I wouldn't call it semantics. "Closest," in the way this article uses it, is exactly what anyone and everyone would assume "closest" is. It is the shortest linear distance between two points.

No, it's not the way "anyone and everyone would assume 'closest' is."

[img.fark.net image 850x478]

Which circle (orbit) is the closest to black? Red or blue? Ask 1000 people and 1000 will say blue. Not a one would say red. In this diagram, red would be Mercury, blue would be Venus, and black would be Earth.

They're talking about planets. Objects. The shortest distance between them.

Orbital paths are not objects. If you wanted to find the shortest distance between two orbital paths, your model would be correct.

In this case, they are talking about planets.

And the average location of a planet over time is its obit. If you are talking absolute location, then its average location is at the center of the orbit, or more or less in the center of the sun. In which case each planet's average location is at the center of the sun displaced by half the distance between its aphelion minus its perihelion, a length that increases as the distance of the planet from the sun increases. And that's a really stupid way of measuring average difference in location - which you seem to want. Orbital average is the way its been done since Copernicus.

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