Astronomers map out Earth's place in the universe among 'Council of Giants'

Mar 11, 2014
This is a diagram showing the brightest galaxies within 20 million light years of the Milky Way, as seen from above. The largest galaxies, here shown in yellow at different points around the dotted line, make up the "Council of Giants." Credit: Marshall McCall / York University

We live in a galaxy known as the Milky Way – a vast conglomeration of 300 billion stars, planets whizzing around them, and clouds of gas and dust floating in between.

Though it has long been known that the Milky Way and its orbiting companion Andromeda are the dominant members of a small group of galaxies, the Local Group, which is about 3 million across, much less was known about our immediate neighbourhood in the universe.

Now, a new paper by York University Physics & Astronomy Professor Marshall McCall, published today in the Monthly Notices of the Royal Astronomical Society, maps out bright galaxies within 35-million light years of the Earth, offering up an expanded picture of what lies beyond our doorstep.

"All bright galaxies within 20 million light years, including us, are organized in a 'Local Sheet' 34-million light years across and only 1.5-million light years thick," says McCall. "The Milky Way and Andromeda are encircled by twelve large galaxies arranged in a ring about 24-million light years across – this 'Council of Giants' stands in gravitational judgment of the Local Group by restricting its range of influence."

This is a diagram showing the brightest galaxies within 20 million light years of the Milky Way, this time viewed from the side. Credit: Marshall McCall / York University

McCall says twelve of the fourteen giants in the Local Sheet, including the Milky Way and Andromeda, are "spiral galaxies" which have highly flattened disks in which are forming. The remaining two are more puffy "elliptical galaxies", whose stellar bulks were laid down long ago. Intriguingly, the two ellipticals sit on opposite sides of the Council. Winds expelled in the earliest phases of their development might have shepherded gas towards the Local Group, thereby helping to build the disks of the Milky Way and Andromeda.

This video is not supported by your browser at this time.
An animation that illustrates the positions of the nearby galaxies, including those in the "Council of Giants," in three dimensions. Credit: Marshall McCall / York University

McCall also examined how galaxies in the Council are spinning. He comments: "Thinking of a galaxy as a screw in a piece of wood, the direction of spin can be described as the direction the screw would move (in or out) if it were turned the same way as the galaxy rotates. Unexpectedly, the spin directions of Council giants are arranged around a small circle on the sky. This unusual alignment might have been set up by gravitational torques imposed by the Milky Way and Andromeda when the universe was smaller."

The boundary defined by the Council has led to insights about the conditions which led to the formation of the Milky Way. Most important, only a very small enhancement in the density of matter in the universe appears to have been required to produce the Local Group. To arrive at such an orderly arrangement as the Local Sheet and its Council, it seems that nearby galaxies must have developed within a pre-existing sheet-like foundation comprised primarily of dark matter.

"Recent surveys of the more distant universe have revealed that lie in sheets and filaments with large regions of empty space called voids in between," says McCall. "The geometry is like that of a sponge. What the new map reveals is that structure akin to that seen on large scales extends down to the smallest."

Explore further: Stream of stars in Andromeda satellite galaxy shows cosmic collision

add to favorites email to friend print save as pdf

Related Stories

Where is Earth located in the galaxy?

Feb 18, 2014

You've probably heard the saying "everything's relative". When you consider our place in the Universe, everything really is relative. I'm recording this halfway up Vancouver Island, in the Pacific Ocean, ...

Hubble sees stars fleeing a cosmic crash

Aug 19, 2013

(Phys.org) —Astronomical pictures sometimes deceive us with tricks of perspective. Right in the center of this image, two spiral galaxies appear to be suffering a spectacular collision, with a host of stars ...

Fat or flat: Getting galaxies into shape

Feb 27, 2014

Australian astronomers have discovered what makes some spiral galaxies fat and bulging while others are flat discs—and it's all about how fast they spin.

Recommended for you

New window on the early Universe

Oct 22, 2014

Scientists at the Universities of Bonn and Cardiff see good times approaching for astrophysicists after hatching a new observational strategy to distill detailed information from galaxies at the edge of ...

Chandra's archives come to life

Oct 22, 2014

Every year, NASA's Chandra X-ray Observatory looks at hundreds of objects throughout space to help expand our understanding of the Universe. Ultimately, these data are stored in the Chandra Data Archive, ...

User comments : 18

Adjust slider to filter visible comments by rank

Display comments: newest first

pianoman
2 / 5 (4) Mar 11, 2014
I'm just a simple 2+2=4 person and maybe a question that comes to mind is irrelevant, Does this information, in any way, conflict with the big bang theory? Thanks.
dogbert
1.4 / 5 (9) Mar 11, 2014
Very interesting until the obligatory insertion of imaginary matter.
msadesign
4.7 / 5 (12) Mar 11, 2014
@pianoman: no, it does not.
@dogbert: sigh.
GSwift7
5 / 5 (11) Mar 11, 2014
Does this information, in any way, conflict with the big bang theory?


It doesn't either confirm nor deny it in any way. It's hard to believe (on human scales), but as big as this local group seems to us, it's really not a big enough bit of space to measure the larger theory of Universal cosmology. Imagine the local group as one single tuft of grass growing in your yard, and imagine the big bang theory as the study of techtonic plate movement. The local group is so small that any effects such as accelerating expansion or curvature of spacetime wouldn't be measurable.
ViperSRT3g
4 / 5 (2) Mar 11, 2014
Now I'm interested in seeing what the data looks like when you begin to include dimmer galaxies.
cantdrive85
1 / 5 (10) Mar 11, 2014
"Unexpectedly, the spin directions of Council giants are arranged around a small circle on the sky. This unusual alignment might have been set up by gravitational torques imposed by the Milky Way and Andromeda when the universe was smaller."

The galaxies are spinning along the axis of the Birkeland currents that course through the current sheet, it's only unexpected when you don't know what to expect.
Q-Star
5 / 5 (13) Mar 11, 2014
The galaxies are spinning along the axis of the Birkeland currents that course through the current sheet, it's only unexpected when you don't know what to expect.


Well then maybe the EU/PC guys should get out there and start making concrete and unambiguous predictions so everyone will know what to expect.
Whydening Gyre
4.2 / 5 (5) Mar 11, 2014
Now I'm interested in seeing what the data looks like when you begin to include dimmer galaxies.

Interestingly enough, you will see a "widening gyre"...:-)
Maggnus
5 / 5 (9) Mar 11, 2014
The galaxies are spinning along the axis of the Birkeland currents that course through the current sheet, it's only unexpected when you don't know what to expect.
Lol cantsupport-his-pseudo-science is really grasping at straws now!
Captain Stumpy
5 / 5 (11) Mar 11, 2014
The galaxies are spinning along the axis of the Birkeland currents that course through the current sheet, it's only unexpected when you don't know what to expect

@CD85
personal conjecture
please provide empirical data to solidify your assertions
skip the EU/IEEE pseudoscience and post from legitimate peer reviewed papers, please

thermodynamics
4.7 / 5 (14) Mar 11, 2014
Cant85: You said: "The galaxies are spinning along the axis of the Birkeland currents that course through the current sheet, it's only unexpected when you don't know what to expect."

Can you just whet our appetite by giving us the current density and charge flow?

How about adding polarity?

Can you predict dipoles that will polarize emissions so we can look in the data?

How about a number for the magnetic fields?

I'm just wantin' to be one of those in the know...
ekim
5 / 5 (12) Mar 11, 2014
Very interesting until the obligatory insertion of imaginary matter.

Neptune was the first planet found by mathematical prediction rather than by empirical observation.
dogbert
1 / 5 (8) Mar 11, 2014
ekim,

Neptune is not now and was not then imaginary.
PhotonX
5 / 5 (8) Mar 11, 2014
The galaxies are spinning along the axis of the Birkeland currents that course through the current sheet, it's only unexpected when you don't know what to expect.


Well then maybe the EU/PC guys should get out there and start making concrete and unambiguous predictions so everyone will know what to expect.
Q-Star took the words right out of my mouth (fingers?). It's like people claiming that Nostradamus "predicted" Hurricane Katrina, but the quatrain only made sense *after* the event. Is it uncharitable to assume that there is no link to point us to where this result was predicted by EU *before* the observation discussed in the article was made? Or did they just forget to "expect" that?
DarkHorse66
5 / 5 (8) Mar 12, 2014
Very interesting until the obligatory insertion of imaginary matter.

Neptune was the first planet found by mathematical prediction rather than by empirical observation.

ekim,

Neptune is not now and was not then imaginary.

A question was asked. And then another; could there be more planets out there? Could we use Newton to predict the most likely spot(s) to look at in the sky...
They couldn't know that for certain until they actually found it, & thus confirmed that their shiny new maths was valid. This is not so different to what is happening with DM & DE at the moment (eg is it real, if it is,what is it ? If it is not real, what is it instead...?, blah, blah..blah)
You've got the benefit of hindsight. They didn't.
http://en.wikiped..._Neptune

Best Regards, DH66

GSwift7
5 / 5 (7) Mar 12, 2014
Now I'm interested in seeing what the data looks like when you begin to include dimmer galaxies


Never satisfied, never enough for you? Sure, I know how this works; If I let you see the dimmer galaxies, you'll just want to see the individual stars next. If I let you see the stars, you'll want the planets. :)

BTW, speaking of dim, I see the words 'Birkland Current' in the thread above.

Very interesting until the obligatory insertion of imaginary matter


Well, there's certainly something that looks like the pull of gravity there, and the only thing we know of that does that is matter. If there's not some kind of matter there, then we'll need to come up with another way of creating a gravity field. There are lots of things we can't directly see, but we measure indirectly. That doesn't mean they aren't real.
yep
1.5 / 5 (8) Mar 14, 2014
"Well, there's certainly something that looks like the pull of gravity there, and the only thing we know of that does that is matter. If there's not some kind of matter there, then we'll need to come up with another way of creating a gravity field. There are lots of things we can't directly see, but we measure indirectly. That doesn't mean they aren't real."

Like Birkland currents?
With fine structure formation aka "filaments"

No dark matter or big bang creationism needed, we have created miniature galaxy formations in the lab and we did not have an imaginary black hole either.
http://adsabs.har....6...87B

Gravity is a pretty weak excuse for small circles, just ask a dog.
http://www.fronti...abstract

marklade
Mar 16, 2014
This comment has been removed by a moderator.
yyz
5 / 5 (4) Mar 16, 2014
A preprint of "A Council of Giants" is available here: http://arxiv.org/abs/1403.3667