Celestia Forums

I'm trying to get a rough estimate as to where our planet was, about mid 1957, as compared to where we are now. I suppose using our sun as a reference point is good enough, if anyone has the latest calculations as to the speed and direction our sun (and thus solar system) is moving in the galaxy. Thus, how far away now (in light minutes, etc.) and in what direction, is the relative point in space where Earth occupied in mid 1957?

"The orbital speed is 217 km/s, equivalent to one light-year every 1,400 years, and one AU every 8 days." - Wiki


"From the book: _Guide to the Galaxy_, 1994; Henbest and Couper; Cambridge University Press.

The Sun is moving towards Lambda Herculis at 20 kilometers per second or 12 miles per second. Or in units "per hour": 72,000 kilometers per hour or 45,000 miles per hour. This speed is in a frame of rest if the other stars were all standing still.

The three-dimensional picture of the Sun's movement through the Galaxy is a little more complicated.

The Sun is moving upwards, out of the plane of the Milky Way, at a speed of 7 kilometers per second. Currently the Sun lies 50 light-years above the mid-plane of the galaxy, and its motion is steadily carrying it further away.

But the gravitational pull of the stars in the Galactic (Milky Way) plane is slowing down the Sun's escape. The astronomer Frank Bash estimates that in 14 million years the sun will reach its maximum height above the Galactic disk. From that 250 light-year position, it will be pulled back towards the plane of the Galaxy. Passing through, it will travel to a point 250 light-years below the disk, then oscillate upwards again to reach its present position 66 million years from now. We crossed the plane 2 million years ago. We are currently in the thick of the galactic disk and our view of distant regions is largely blocked by dust but 10-20 million years from now, our motion will allow a full view of our starry galaxy." - Stanford SOLAR Center

That would put Sol some 342,399,960,000 km ... back that way

Thanks so much for the info! It has been quite a while since I last heard general estimates as to our motion, and I remember one astronomy source back in the 80's stating that our system is headed in the direction of Taurus, and at a slightly different velocity. The current info you gave is much appreciated, and I'm thankful at how technology has provided better data these days!

Here's another value, from
Title The Solar Motion Relative to the Local Group
Author(s) St?©phane Courteau and Sidney van den Bergh
Identifiers The Astronomical Journal, volume 118 (1999), pages 337?€“345
DOI: 10.1086/300942
Bibcode: 1999AJ....118..337C

New data on the membership of the Local Group (LG) are used, in conjunction with new and improved radial velocity data, to refine the derivation of the motion of the Sun relative to the LG. The Sun is found to be moving with a velocity of V=306?±18 km s-1 toward an apex at l=99?°?±5?° and b=-4?°?±4?°.

See
http://www.journals.uchicago.edu/cgi-bi ... 086/300942

Thanks to you also, Selden!

Do you mind if I ask why 1957?

bh wrote:Do you mind if I ask why 1957?

bh:

Maybe the man wants to know how far away his real place of birth he really is...

//Tech2000

hehe... 1957 is my birthday.

On what planet?
Only the gas giants have more than 1957 days per year.

bh wrote:Do you mind if I ask why 1957?

I just have a fascination with that era, and dabbling into something regarding "what exact space" when looking at "when", etc.

But, 1957 was when I saw my first starry sky, at the age of 4. A sight I'll never forget, and it gave me the fascination and enthusiasm I have for astronomy to this day.

Fantastic Starnighter... plus that makes you four years older than me!

bh wrote:Fantastic Starnighter... plus that makes you four years older than me!

Yes, four years older . It's great to know that other baby boomers are still out here, and shared the same starry skies as I did back then!

Still here booming, only not quite as loudly as I used to! Learned a few constellations early on, and especially how to find Polaris (age 10) for navigation while sailing. I only got my first ever look at Andromeda (M31) about 6 months ago, with the help of a pair of 40x binoculars and Celestia... faint and fuzzy, but I did see it.

LordFerret wrote:Still here booming, only not quite as loudly as I used to! Learned a few constellations early on, and especially how to find Polaris (age 10) for navigation while sailing. I only got my first ever look at Andromeda (M31) about 6 months ago, with the help of a pair of 40x binoculars and Celestia... faint and fuzzy, but I did see it.

I was lucky to see M-31 very early in my teens, with a small scope, but like you, did learn the constellations very early on. Did you get to see M-27 ever yet? That was so impressive in even a small scope.

No, not yet. But now that you've brought it to my attention I'll have to start up Celestia and see when optimal viewing for my area is... and where I can find it.

LordFerret wrote:No, not yet. But now that you've brought it to my attention I'll have to start up Celestia and see when optimal viewing for my area is... and where I can find it.

In Vulpecula, between the tip of the northern cross(Albireo, in Cygnus)) and Sagitta. Just a blurr in binocs or small scope, but the famous "dumb-bell shape is definitely seen!