Which Star is Closest To the Earth?

[The idea]

I know that it's called the Sun. We assume that it is the star that is closest to the Earth. The question is: given the entire astronomical universe of stars, what can we say, without referring to the Earth, to identify the one star that is closest to the Earth?

 

[Major Billy]

the galactic coordinate system

 

[Atlas]

... what can we say, without referring to the Earth, to identify the one star that is closest to the Earth?

I don't get the question. "Closest" is a distance phenomonon. Distance is measured between two things.

Why would you leave out one thing that you are attempting to find close objects to?

You're saying, aren't you, to skip apparent size and measured radiation as qualities suggesting closeness because those are apparent from out point of view - which is Earth.

Sorry - I'm confused. I don't see how you can get at closeness if you're not allowed to refer to the object things are close to.

What are you really driving at?

 

[Checkmite]

I think Idea is asking what proper scientific designation (like "Ursa Major, Gamma" for instance) would be used to refer to our sun, besides "Our Sun".

Since stars' names are relative to the constellations they appear in, and the Sun does not belong to a constellation, I'm not sure what the answer would be.

 

[Zombified]

The name of the star is The Sun, or if you want to be all classical about it, Sol.

 

[Ladewig]

The star closest to Proxima Centauri would be one way of describing it, but who are you trying to describe it to.

A clever way to give someone directions on how to get to our star is recordedhere.
The plaque gives the distances from several identifiable pulsars (relatively) near the Sun.

 

[davidhorman]

The star closest to Proxima Centauri would be one way of describing it, but who are you trying to describe it to.

The star closest to Proxima Centauri is either Alpha Centauri A or B.

David

 

[wollery]

We'd call it Sol and once we'd got in the vicinity by following the pulsar map we could use the three dimensional map of the local Solar neighbourhood, which includes full 3 dimensional space velocity information. We could also identify it from its absolute magnitude in several passbands as well as its spectrum across a vast wavelength range.

Oh and I might also mention that once within ~1ly Jupiter and Saturn would start to be discernable, if a little faint!

 

[The idea]

[...] once we'd got in the vicinity by following the pulsar map [...]

Where is a diagram of the pulsar map? What happens if two completely different regions of the universe are described by the same pulsar map?

 

[The Don]

What happens if two completely different regions of the universe are described by the same pulsar map?

If this unlikely circumstance happened they would be indistinguishable using the pulsar map. It's like saying if there were two identical rooms and you were rendered unconcious and placed in one of them, how could you tell which one you were in.

 

[davidhorman]

What happens if two completely different regions of the universe are described by the same pulsar map?

Not withstanding how incredibly unlikely this is (I think it's worth emphasising), you'd just look a bit further for more pulsars to establish your position.

David

 

[geni]

If you reaaly want to locate yourself against the entire universe you waould start with the quasars and then go to the pulsars

 

[wollery]

Where is a diagram of the pulsar map? What happens if two completely different regions of the universe are described by the same pulsar map?

You might want to look here; pulsar.princeton.edu/pulsar/map/PulsarMap.html



I also came across this, from a site about an alien abduction conference!

One must-have at this year's event was the "Galactitag." The 1-inch, oval-shaped metal tag sold for $12.95 and included the money-back guarantee of a safe return for abductees who were "lost in space." The label explained that the tag is imprinted with a "pulsar map" instantly understood by aliens -- most likely eliminating any need to phone home.

I just want to know, if it doesn't work, how would you claim your money back?

 

[Ladewig]

Where is a diagram of the pulsar map? What happens if two completely different regions of the universe are described by the same pulsar map?

In the Pioneer plaque, the pulsar map is labelled "4." It not only includes the distance from the Sun to 15 pulsars, it also includes the periods of each pulsar. This map is useful to anybody within a few hundred light-years (give or take an order of magnitude) of the Sun. Given that our galaxy is 100,000 light years in diameter, the map has limited use, but then again, it was designed for a very small area of space.

Now if you are asking how to give directions to our location to someone in the Andromeda galaxy, then you have a problem. They are 2.9 million light years away.