B Is blue shift as common as red shift?

[BL4CKB0X97]

A somewhat trivial question, but I hear of redshift a lot more than blue.

And is possible to get a list of galaxies that display these attributes? I would like to use the data for a project.

Thanks guys.

 

[davenn]

A somewhat trivial question, but I hear of redshift a lot more than blue.

well considering pretty much everything outside of our local group of galaxies is moving away from us ... yes red shift is more common

blue shift is measured with some of our local group eg M31 that is coming towards us

within any particular galaxy red and blue shift can be observed for the parts moving away and towards us as the galaxy rotates

cannot find a decent graphic

edit
the best I could find

This image from the Very Large Baseline Array (VLBA) shows what the galaxy M33 would look like if you could see in radio waves.

 

[davenn]

OK
another one ...

couldn't find a credit for this one

 

[BL4CKB0X97]

Thanks

 

[fresh_42]

... yes red shift is more common

Never, ever. The universe is just one thing, but do you have any idea how many radar based speed controls they have over here?

 

[Bandersnatch]

And is possible to get a list of galaxies that display these attributes? I would like to use the data for a project.

You can query the NED database for galaxies with redshift < 0.
https://ned.ipac.caltech.edu/ui/?q=byparams

 

[BL4CKB0X97]

You can query the NED database for galaxies with redshift < 0.
https://ned.ipac.caltech.edu/ui/?q=byparams

Thanks

 

[davenn]

Never, ever. The universe is just one thing, but do you have any idea how many radar based speed controls they have over here?

what are you talking about ??

 

[fresh_42]

This wasn't meant serioiusly, of course.
I meant those: https://en.wikipedia.org/wiki/Traffic_enforcement_camera
They should all measure a blue shifted echo.

 

[Vanadium 50]

They should all measure a blue shifted echo.

Do they? Do they catch you coming or going?

 

[fresh_42]

Do they? Do they catch you coming or going?

Coming, they need a photo of the plate and the driver.

 

[Vanadium 50]

they need a photo of the plate and the driver.

Good point. But in a dozen or so states, front plates are not required.

 

[BL4CKB0X97]

Coming, they need a photo of the plate and the driver.

Good point. But in a dozen or so states, front plates are not required.

Did i miss something?

I'm rather confused.

 

[davenn]

Did i miss something?

I'm rather confused.

it's OK
those guys veered off-course

was there anything else relating to your original query that can be discussed
or did it get answered well enough ?cheers
Dave

 

[BL4CKB0X97]

it's OK
those guys veered off-course

was there anything else relating to your original query that can be discussed
or did it get answered well enough ?cheers
Dave

I think that's it. Thanks.

 

[CygnusX-1]

There are galaxies in the Virgo cluster that have blueshifts. These galaxies are on the far side of the cluster's center and are falling toward it--and thus toward us.

Here is a report on the largest blueshift ever seen in the main body of an object: Found: The Fasting Approaching Object in the Universe by Ken Croswell.

 

[Alan McIntire]

A somewhat trivial question, but I hear of redshift a lot more than blue.

And is possible to get a list of galaxies that display these attributes? I would like to use the data for a project.

Thanks guys.

In terms of galaxies, no. The Andromeda Galaxy is approaching us, but Galaxies not in our local group are generally receding from us.
In terms of stars in our own galaxy, blue shift is quite common. In fact, that's how scientists figured out in which direction our sun is orbiting and rougly
how fast the period of rotation around the center of the galaxy is.

Stars closer to the center of the galaxy and ahead of us in their orbits generally show a red shift- they're rotating faster than the sun and receding from us.
Stars closer to the center of the galay and behind us in their orbits generally show a blue shift- they're rotating faster than the sun and getting closer to us.

Conversely, stars in the opposite quadrants, farther from us are the opposite. Depending on your orientation, stars in Quadrants I and III may show a red shift,
stars in Quadrants II and IV a blue shift.

 

[BL4CKB0X97]

In terms of galaxies, no. The Andromeda Galaxy is approaching us, but Galaxies not in our local group are generally receding from us.
In terms of stars in our own galaxy, blue shift is quite common. In fact, that's how scientists figured out in which direction our sun is orbiting and rougly
how fast the period of rotation around the center of the galaxy is.

Stars closer to the center of the galaxy and ahead of us in their orbits generally show a red shift- they're rotating faster than the sun and receding from us.
Stars closer to the center of the galay and behind us in their orbits generally show a blue shift- they're rotating faster than the sun and getting closer to us.
View attachment 206770

Conversely, stars in the opposite quadrants, farther from us are the opposite. Depending on your orientation, stars in Quadrants I and III may show a red shift,
stars in Quadrants II and IV a blue shift.

Sorry to revive a dead post...

Should you have enough data, would it not be possible to create a map of galaxies that are going away or coming towards us and the direction they are moving,in order to get a rough position of the original point of expansion?

It could also be used for universal reference points for navigation, similar to the use if pulsars.

 

[russ_watters]

Sorry to revive a dead post...

Should you have enough data, would it not be possible to create a map of galaxies that are going away or coming towards us and the direction they are moving,in order to get a rough position of the original point of expansion?

It could also be used for universal reference points for navigation, similar to the use if pulsars.

We have our relative motion with respect to the CMB we can correct for, but that doesn't give us a center of expansion, because there isn't one.

And again: outside our local group of galaxies, all of them are moving away from us -- just not quite all at the same speed vs distance ratio.

 

[Bob Teo]

Considering that all distant galaxies are moving away from us (Russ: would you give me a reference to this fact? Thanks), doesn't it make Earth the centre of the universe?

 

[PAllen]

Considering that all distant galaxies are moving away from us (Russ: would you give me a reference to this fact? Thanks), doesn't it make Earth the centre of the universe?

https://www.physicsforums.com/insights/big-bang-happen/

 

[phinds]

Considering that all distant galaxies are moving away from us (Russ: would you give me a reference to this fact? Thanks), doesn't it make Earth the centre of the universe?

Please read the link in my signature

 

[russ_watters]

Considering that all distant galaxies are moving away from us (Russ: would you give me a reference to this fact? Thanks), doesn't it make Earth the centre of the universe?

There are lots of sources if you google it (something like "list of blue shifted galaxies"), though there is some crackpottery available accidentally. But a bite-sized factoid:

With the help of galaxy surveys, astronomers have found that around 100 galaxies are moving towards us. Compared to the numbers of galaxies that we know of (hundreds of billions), blue-shifted galaxies are seemingly quite rare. Those that are moving towards us are either part of our Local Group, which means that we are gravitationally connected to each other, or they are found in the Virgo Cluster which everything in our Local Group is moving towards. The galaxies M90, M86 and M98 are all in the Virgo Cluster and all show blue shifts.

https://www.spaceanswers.com/solar-system/why-are-planets-closer-to-the-sun-more-dense/
[multiple questions answered in that link]

Here's a database of them:
http://ned.ipac.caltech.edu/

Another answer, from a university:
http://www4.hcmut.edu.vn/~huynhqlinh/olympicvl/tailieu/physlink_askexpert/ae384.cfm.htm

As far as what this means for our place in the universe, @phinds' link is good, describing the geometry. In short though, we can say we're at the center of what we can see, but that's just a consequence of the finite speed of light. Everyone, everywhere would be able to say the same thing. There are a number of analogies to demonstrate: dots on the surface of expanding sphere, expanding rasin muffin, etc.

 

[stefan r]

And again: outside our local group of galaxies, all of them are moving away from us -- just not quite all at the same speed vs distance ratio.

The universe is too messy for that generalization.
Messier 90, messier 98, and messier 86:

...[Messier 86] is approaching the Milky Way at 244 km/s...

...doesn't it make Earth the centre of the universe?

If you make a map of travel distances from your house then your house should be the center of the map. This does not prove a "flat earth" theory. Flat maps of Earth's surface certainly do exist. This can be proven in any lab with a printer and internet connection.

You can say "the solar system is the center of all observations made by human astronomers". The center of most observations should be inside the sun. On any given second the night side of Earth is the center of most observations. In any second before the mid 20th century the night side of Earth was the center of all known observations of objects that are outside of the solar system.

 

[davenn]

The universe is too messy for that generalization.
Messier 90, messier 98, and messier 86:

and if you read Russ's post #23, he addressed that already

 

[russ_watters]

Yes, I got a particular wrong (missed the existence of a nearby cluster our cluster is moving toward). But it doesn't change the point and I addressed it in my follow-up.

 

[sophiecentaur]

Considering that all distant galaxies are moving away from us (Russ: would you give me a reference to this fact? Thanks), doesn't it make Earth the centre of the universe?

. . . . . and every other place, too. It is Space that is expanding and not just things moving away from us. You must have heard the old chestnut about dots, drawn on the surface of a balloon. As the balloon is inflated more and more, they all get more distant from each other but no particular dot is in the 'middle'. Think along those lines.