Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Zer0 on 19/03/2018 18:09:09
-
The Closest or Nearest Star to Planet Earth in terms of Distance is . . . ?
-
Warning - Trick question. The answer is he star Sol (aka the sun).
Sorry. Did I give that away? :)
-
In terms of a runner-up, it depends on when you look...
https://en.wikipedia.org/wiki/List_of_nearest_stars_and_brown_dwarfs#Future_and_past
Scholz's star passed through the Sun's Oort cloud about 70,000 years ago, passing within 1 light year from the Sun. But it is a very faint star, and would not have been visible to the human eye, even at its closest.
https://en.wikipedia.org/wiki/Scholz%27s_star#Solar_System_flyby
-
I was going to say Elton John...
-
I see your Elton John and raise you Boy George.
-
My vote is for Barbara Hendrix, who, like Scholz's star, passes almost un-noticed by the masses.
-
My vote is for Barbara Hendrix
Coo, didn’t know The Man had a daughter!
-
Coo, didn’t know The Man had a daughter!
If that's Jimi, he would have had to be quick off the mark!!
-
I see your Elton John and raise you Boy George.
I call. I have Robert Plant, John Paul Jones and Jimmy Page = Led Zeppelin - I win! Yay Pete!
-
In terms of a runner-up, it depends on when you look...
https://en.wikipedia.org/wiki/List_of_nearest_stars_and_brown_dwarfs#Future_and_past
Scholz's star passed through the Sun's Oort cloud about 70,000 years ago, passing within 1 light year from the Sun. But it is a very faint star, and would not have been visible to the human eye, even at its closest.
https://en.wikipedia.org/wiki/Scholz%27s_star#Solar_System_flyby
Thanks Evan,
Somewhat like a variation of the Nemesis Hypothesis (https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star))
I didn't realize there were so many close flybys. According to your list, Gliese 710 passed within 0.14–0.27 ly, 1.3 million years ago, I think, and HIP 85605 passed within 0.13–0.65 ly 240–470 thousand years ago.
Pluto's orbit is between 0.00044 and 0.00079 light years. So, 0.14 or 0.15 lightyears isn't that close, but perhaps close enough to be uncomfortable.
-
(https://upload.wikimedia.org/wikipedia/commons/thumb/e/e9/Near-stars-past-future-en.svg/600px-Near-stars-past-future-en.svg.png)
It looks like we need to kick our space program into high gear. We have about 10,000 years to get to Barnard's Star, otherwise we may never have another chance. 20,000 years to get to Lalande 21185 before it is gone.
The Centauri cluster of stars will be hanging around a little bit longer, but still, it might not hurt to try to get a rocket out there in 20,000 to 30,000 years. :)
And, with our current rocket speeds, we may have to get an early start on some of the trips.
-
Fascinating graph, Clifford. It's amazing what interesting information can emerge from a not-so-serious thread. Thanks.
-
@CliffordK I have to echo @Bill S comment.
That chart is fascinating. I knew some stars are getting closer, but didn’t realise they had comet like tracks. The dynamics of this system would be interesting to know.
-
@CliffordK I have to echo @Bill S comment.
That chart is fascinating. I knew some stars are getting closer, but didn’t realise they had comet like tracks. The dynamics of this system would be interesting to know.
They don't. The graph shows distance vs. time. The shape shown for the the curves is an artifact of this.
Assume that the asterisks in the first line below is a star passing our solar system ( the asterisk in the second line) at some fixed speed in a straight line. Thus each asterisk is the star's position relative to our sun at fixed time period apart.
**********************************
----------------*-----------------
A line joining any given asterisk on the top line with the asterisk on the bottom line gives the star's distance for that moment in time.
If you were to plot the individual lengths of these lines on a graph, you'd get a curve like the ones shown in the provided graph. You would be basically be plotting the graph the the function sqrt(x^2+(vt)^2), where x is the distance of closest approach, v is the speed of the star relative to the Sun, and t is the time as measured from the moment of closest approach
-
@Janus thanks, I hadn’t sat down and thought that through.
Still very interesting view of relative motions of what the ancients call the fixed stars. If only they knew!
-
It also means that the Milky Way is a far more dynamic place than simply a group of stars in a spiral form orbiting a central mass.
-
the Milky Way is a far more dynamic place...
As well as the general circular motion around the center of our galaxy:
- Stars closer towards the center will "overtake" stars farther out
- each star will have its own eccentricity: moving in and out, forwards and backwards, compared to adjacent stars in circular orbits
- each star will have its own velocity up and down in the disk of the galaxy. The mass of the galactic plane will lead to stars bobbing up and down within the galactic disk.
- stars passing close by each other will deflect each other, leading to random motions depending on what direction they pass each other (gravitational slingshot)
So there is a local chaos superimposed on the spiral arms of the galaxy, which is in turn superimposed on the general circular rotation of the galaxy.
-
The discussion about what to measure about a star has been split off into a separate thread:
https://www.thenakedscientists.com/forum/index.php?topic=72648.msg537053#msg537053
-
Sun?)
-
Q - Which is the Closest Star to Planet Earth ?
Subjective Answer - None of the Above.
Possible Valid Candidates -
1) The Sun. ( Royal Astronomical Society ) 👊
2) Flybys Stars. ( Wise TNS Members ) 👍
3) https://www.energy.gov/articles/creating-star-earth (Personal Favourite Choice ) 👌
😁✌