time motion

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chuck hutchinson
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time motion

Post by chuck hutchinson » Sun Nov 29, 2015 2:20 am

Over the past several decades, has there been enough photography that when put together in time order, would show motion of distant objects, like the Orion nebulae?

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Re: time motion

Post by geckzilla » Sun Nov 29, 2015 2:53 am

If you're looking at small enough movements, yes. Almost everything out there has moved measurably. A few things move spectacularly fast. One of my favorite "movements" are the minute changes that the Sun's gravity has on distant objects. It's not a real movement, but it's fascinating to me that these tiny wobbles are measurable.
http://backreaction.blogspot.com/2015/0 ... l?spref=tw

Regarding the Orion Nebula itself, you wouldn't notice any change at all if you compared one local astrophotographer's picture to another. You'd probably detect some small changes if you use a fancy enough telescope, though. Hubble's been kicking around up there for 25 years and that's possibly enough time for some particularly fast moving thing to be noticed, like a Herbig Haro object.

As Earth moves through its orbit, the apparent locations of stars also wobble back and forth. This is known as parallax movement. It's also not a real movement, but it's pretty useful for measuring the distances to stars.
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Re: time motion

Post by Ann » Sun Nov 29, 2015 6:18 am

61 Cygni. Photo: IndividusObservantis.
This is 61 Cygni, a pair of K-type dwarfs located 11.4 light-years away. They have an easily measured proper motion.
Barnard's Star. Photo: Steve Quirk.
An even more dramatic example of stellar proper motion is seen in Barnard's star, a faint red dwarf star located six light-years away.
Wikipedia wrote:
The star is named for American astronomer E. E. Barnard. He was not the first to observe the star (it appeared on Harvard University plates in 1888 and 1890), but in 1916 he measured its proper motion as 10.3 arcseconds per year, which remains the largest known proper motion of any star relative to the Solar System.
Another dramatic example of motion in space that can easily be detected by human instruments is the expansion of the Crab Nebula.

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Re: time motion

Post by Markus Schwarz » Mon Nov 30, 2015 8:53 am

There is this composition of images showing the motion of stars around the central black hole of the Milky Way. A computer animation based on these images can be found here.

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Re: time motion

Post by starsurfer » Mon Nov 30, 2015 6:44 pm

chuck hutchinson wrote:Over the past several decades, has there been enough photography that when put together in time order, would show motion of distant objects, like the Orion nebulae?
In time lapse photography, you wouldn't be able to see the movement of nebulae but you can see the expansion of various nebulae such as the Crab Nebula supernova remnant and the GK Persei nova remnant shell. Another animation of the expansion of GK Persei can be seen here.