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it is interesting that earth spends more time with mercury closer than venus due to orbital mechanics, but the entire premise of the article is just an annoying

by knome 3y ago

it is interesting that earth spends more time with mercury closer than venus due to orbital mechanics, but the entire premise of the article is just an annoying "gotcha" twist of language. the planet earth is ever nearest to is Venus, which is what people will mean by "closest neighbor". if you work from home and your next door neighbor works at the office, it doesn't make the retired lady in the next house over your closest neighbor, regardless of spending more time in closer relative proximity to her.

mercuryftw123 3y ago
I don't think that way. It's more like this: your two blocks down the street neighbor drives by you every morning, would you classify it being closer to you? Because that's how we look at the Venus at the moment. Mercury should be the real neighbor.
- vertis 3y ago
  I think a better example is neighbour 1 drives past your house once a day and neighbour 2 drives past 10 times a day on the main road several blocks further from your house. If you needed a lift somewhere (or some other reason to interact), you can either wait patiently for N1 to drive past or you can walk the several blocks to the main road, and then wait less time for N2.
- inopinatus 3y ago
  If we're talking about transportation, well then. The efficient transfer to Mercury is via Venus transfer, so it is farther by such reckoning. In terms of delta-v budget, Venus is actually closer than Mars, unless you wanted to, say, visit the surface. See https://upload.wikimedia.org/wikipedia/commons/9/93/Solar_system_delta_v_map.svg https://upload.wikimedia.org/wikipedia/commons/9/93/Solar_sy..., essential information to plan your next interplanetary holiday
  - aidenn0 3y ago
    So to stretch the analogy to its limits, what if you have someone who lives directly across the freeway from you, and a neighbor whose house is next to the overpass that lets you cross the freeway.
davidgrenier 3y ago
I had never heard of the concept of closest average neigbor before. When I read it, I assumed it meant: draw a straight line between the two bodies, that is the current distance between the two bodies, now average it over a couple of years of motion of these two bodies in space.
manojlds 3y ago
But in this case the house itself is moving. If Mercury and Venus had people, which of those people is our closest neighbour?
- otabdeveloper4 3y ago
  Whichever one has smaller delta-v.
- adql 3y ago
  The one with smallest ping
0xFF0123 3y ago
Taking your argument to the extreme, if there was a planet that somehow brushed by extremely closely to Earth every thousand years, that planet would be the closest neighbor? I would argue not. I think the average is more meaningful.
- Ensorceled 3y ago
  To return to the analogy, if once a year my brother-in-law parks their RV in my drive, nobody would be confused about who my closest neighbour is. I would argue that MOST people would disagree with you and would say Venus is our closest neighbour but once every 1000 years wobbly Erebus returns from the dark to scare the hell out of us.
- xwdv 3y ago
  If I have a house and you have a house next to me yet neither of us are ever home, we are still neighbors no matter where in the world we are. Similarly, the entire area earth and Venus clear with their orbits is the planet’s “home”, therefore, we only have two neighbors, Mars and Venus, and Venus is probably the closest.
  - hgsgm 3y ago
    It doesn't take me a year to walk a lap around my home. Maybe you could say that the orbit is territory that a planet roams, like a nomadic person or migratory bird.
- thx-2718 3y ago
  Both have independently useful meaning. The average closest planet would be useful for regularly traveling between two places. The closest at any one time is useful for planning intermittent trips. Let's say we had to pick 2 equal planets we would travel to. Adding the stipulation that planet A is closer on average to HOME than planet B; Planet B has the shortest distance to HOME. If travel is cheap then planet A is more useful to travel to since you can afford to do it regularly. If travel is expensive then planet B is more useful since you can't afford travel all the time and rather need to make sure each trip is worth. If you live in a city it's more reasonable to go to the grocery every week. If you live in a rural area it's more reasonable to wait for the Shwan truck (type of grocery delivery) once a month.
dreamcompiler 3y ago
> it doesn't make the retired lady in the next house over your closest neighbor, regardless of spending more time in closer relative proximity to her. It does matter a lot if you're trying to send a rocket to a particular one of those neighbors at a particular time.
- zamadatix 3y ago
  In that case you probably want a delta-v not distance.

by knome 3y ago

mercuryftw123 3y ago

I don't think that way. It's more like this: your two blocks down the street neighbor drives by you every morning, would you classify it being closer to you? Because that's how we look at the Venus at the moment. Mercury should be the real neighbor.

vertis 3y ago
I think a better example is neighbour 1 drives past your house once a day and neighbour 2 drives past 10 times a day on the main road several blocks further from your house. If you needed a lift somewhere (or some other reason to interact), you can either wait patiently for N1 to drive past or you can walk the several blocks to the main road, and then wait less time for N2.
inopinatus 3y ago
If we're talking about transportation, well then. The efficient transfer to Mercury is via Venus transfer, so it is farther by such reckoning. In terms of delta-v budget, Venus is actually closer than Mars, unless you wanted to, say, visit the surface. See https://upload.wikimedia.org/wikipedia/commons/9/93/Solar_system_delta_v_map.svg https://upload.wikimedia.org/wikipedia/commons/9/93/Solar_sy..., essential information to plan your next interplanetary holiday
- aidenn0 3y ago
  So to stretch the analogy to its limits, what if you have someone who lives directly across the freeway from you, and a neighbor whose house is next to the overpass that lets you cross the freeway.

davidgrenier 3y ago

I had never heard of the concept of closest average neigbor before. When I read it, I assumed it meant: draw a straight line between the two bodies, that is the current distance between the two bodies, now average it over a couple of years of motion of these two bodies in space.

manojlds 3y ago

But in this case the house itself is moving. If Mercury and Venus had people, which of those people is our closest neighbour?

otabdeveloper4 3y ago
Whichever one has smaller delta-v.
adql 3y ago
The one with smallest ping

0xFF0123 3y ago

Taking your argument to the extreme, if there was a planet that somehow brushed by extremely closely to Earth every thousand years, that planet would be the closest neighbor? I would argue not. I think the average is more meaningful.

Ensorceled 3y ago
To return to the analogy, if once a year my brother-in-law parks their RV in my drive, nobody would be confused about who my closest neighbour is. I would argue that MOST people would disagree with you and would say Venus is our closest neighbour but once every 1000 years wobbly Erebus returns from the dark to scare the hell out of us.
xwdv 3y ago
If I have a house and you have a house next to me yet neither of us are ever home, we are still neighbors no matter where in the world we are. Similarly, the entire area earth and Venus clear with their orbits is the planet’s “home”, therefore, we only have two neighbors, Mars and Venus, and Venus is probably the closest.
- hgsgm 3y ago
  It doesn't take me a year to walk a lap around my home. Maybe you could say that the orbit is territory that a planet roams, like a nomadic person or migratory bird.
thx-2718 3y ago
Both have independently useful meaning. The average closest planet would be useful for regularly traveling between two places. The closest at any one time is useful for planning intermittent trips. Let's say we had to pick 2 equal planets we would travel to. Adding the stipulation that planet A is closer on average to HOME than planet B; Planet B has the shortest distance to HOME. If travel is cheap then planet A is more useful to travel to since you can afford to do it regularly. If travel is expensive then planet B is more useful since you can't afford travel all the time and rather need to make sure each trip is worth. If you live in a city it's more reasonable to go to the grocery every week. If you live in a rural area it's more reasonable to wait for the Shwan truck (type of grocery delivery) once a month.

dreamcompiler 3y ago

> it doesn't make the retired lady in the next house over your closest neighbor, regardless of spending more time in closer relative proximity to her. It does matter a lot if you're trying to send a rocket to a particular one of those neighbors at a particular time.

zamadatix 3y ago
In that case you probably want a delta-v not distance.