Astronomers discover galaxies spin like clockwork

March 13, 2018, International Centre for Radio Astronomy Research
Astronomers discover galaxies spin like clockwork
This Hubble image reveals the gigantic Pinwheel galaxy, one of the best known examples of "grand design spirals", and its supergiant star-forming regions in unprecedented detail. The image is the largest and most detailed photo of a spiral galaxy ever released from Hubble. Credit: ESA/NASA

Astronomers have discovered that all galaxies rotate once every billion years, no matter how big they are.

The Earth spinning around on its axis once gives us the length of a day, and a complete orbit of the Earth around the Sun gives us a year.

"It's not Swiss watch precision," said Professor Gerhardt Meurer from the UWA node of the International Centre for Radio Astronomy Research (ICRAR).

"But regardless of whether a galaxy is very big or very small, if you could sit on the extreme of its disk as it spins, it would take you about a billion years to go all the way round."

Professor Meurer said that by using simple maths, you can show all of the same size have the same average interior density.

"Discovering such regularity in galaxies really helps us to better understand the mechanics that make them tick-you won't find a dense galaxy rotating quickly, while another with the same size but lower density is rotating more slowly," he said.

Professor Meurer and his team also found evidence of older stars existing out to the edge of galaxies.

"Based on existing models, we expected to find a thin population of young stars at the very edge of the galactic disks we studied," he said.

Astronomers have discovered that all galaxies rotate once every billion years, no matter how big they are. Credit: ICRAR

"But instead of finding just gas and newly formed stars at the edges of their disks, we also found a significant population of older stars along with the thin smattering of young and ."

"This is an important result because knowing where a galaxy ends means we astronomers can limit our observations and not waste time, effort and computer processing power on studying data from beyond that point," said Professor Meurer.

"So because of this work, we now know that galaxies rotate once every billion years, with a sharp edge that's populated with a mixture of interstellar gas, with both old and ."

Professor Meurer said that the next generation of radio telescopes, like the soon-to-be-built Square Kilometre Array (SKA), will generate enormous amounts of data, and knowing where the edge of a galaxy lies will reduce the needed to search through the data.

"When the SKA comes online in the next decade, we'll need as much help as we can get to characterise the billions of galaxies these telescopes will soon make available to us."

Explore further: Study of distant galaxies challenges the understanding of how stars form

More information: 'Cosmic clocks: A Tight Radius - Velocity Relationship for HI-Selected Galaxies', Monthly Notices of the Royal Astronomical Society March 14th, 2018.

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cantdrive85
1 / 5 (5) Mar 14, 2018
A universal model to explain this common rotation;
http://www.ptep-o...1-13.PDF
http://www.ptep-o...3-01.PDF
No fearie dust needed!
Macksb
1 / 5 (2) Mar 14, 2018
Periodic oscillators have a tendency to synchronize the periods of their oscillations.

This is an astonishing example.
windrunner
not rated yet Mar 14, 2018
Seems odd that the maximum number of rotations that the oldest galaxy could possibly have
made in universe is 14. I assume that the spun a lot faster when they were younger - yes?
Merrit
not rated yet Mar 14, 2018
I would imagine this is just a limit imposed by the origin of the universe. It just wasn't possible to have orbits longer than that so every galaxy has a similar rotation.
Ducku
1 / 5 (2) Mar 15, 2018
Mike McCulloch's quantised inertia theory ( https://link.spri...7-3128-6 ) predicted exactly this in 2016 - http://physicsfro...hsc.html

There is no dark matter.
granville583762
5 / 5 (5) Mar 15, 2018
Exactly, it says a lot darkmatter, they spin the same, irrespective of mass. There is no darkmatter, its going to hang around a little longer as it is a rice bowl for a lot of people. But where the rice is coming from is a mystery, it must be in the dark matter proves you can make a living out of some thing that does not exist.
Mike McCulloch's quantised inertia theory ( https://link.spri...7-3128-6

There is no dark matter.

cortezz
5 / 5 (2) Mar 15, 2018
Mike McCulloch's quantised inertia theory ( https://link.spri...7-3128-6

There is no dark matter.

From the paper: "so quantised inertia predicts a change in galaxy rotation with time". Isn't this excatly what is not observed if all galaxies rotate like clockwork? Or am I not getting something.
granville583762
5 / 5 (3) Mar 15, 2018
Fritz Zwicky could see the mass he measured, there is no darkmatter.

Fritz Zwicky calculated the gravitational mass of the Coma galaxy cluster within the cluster and obtained a value at least 400 times greater than their luminosity, implying there is matter that is not physically visually visible. At least he's calling what it is "unseen matter" he does not seem to be endowing it with magical properties
Fritz Zwicky was not creating additional matter he was measuring the effects of gravitation mass of mass he could not physically visually see, the mass was visible to be able to measure its effects. The mass was visible so it was not darkmatter so he had not discovered darkmatter. There is no darkmatter!
granville583762
5 / 5 (3) Mar 15, 2018
The darkmatter bandwagon fallacy

This is why everyone jumped on the darkmatter bandwagon to prove that darkmatter was responsible for galactic rotation because darkmatter did not exit, because its known galaxies rotate the same, irrespective of mass!
granville583762
5 / 5 (3) Mar 15, 2018
The orbital period of galactic stars

Stars are 6.5 light years apart on average in galaxies where the orbital period of the galaxy has to match the orbital period of two stars 6.5Lys apart. This is simply binary orbital mechanics to keep the galactic stars apart which is why all galaxies rotate the same, because the average distance between galactic stars, no matter how many stars the galaxy has is 6.5 Lys.
billpress11
5 / 5 (2) Mar 15, 2018
It was my understanding that our Milky Way rotated about once every 200 to 250 million years. So what gives?

Quote from link below:
"More mind-blowing is that this mass of stars, gas, planets and other objects are all spinning. Just like a pinwheel. It's spinning at 270 kilometers per second (168 miles per second) and takes about 200 million years to complete one rotation, according to the National Radio Astronomy Observatory. "

https://www.unive...otation/
Ducku
5 / 5 (1) Mar 16, 2018
Mike McCulloch's quantised inertia theory ( https://link.spri...7-3128-6

"6. If an object in deep space, far from other objects (in the low acceleration MiHsC regime) spins or moves, then objects nearby (cosmically speaking) should tend to spin or move in the same sense. This is similar to the Tajmar effect in the lab, also predicted by MiHsC."

Here is an article explaining it: https://arxiv.org...3266.pdf
antialias_physorg
4.3 / 5 (6) Mar 16, 2018
It was my understanding that our Milky Way rotated about once every 200 to 250 million years. So what gives?

Our sun revolves around the galactic center every 200-250mn years. But not all parts of the galaxy rotate at the same speed. From the above article:
"But regardless of whether a galaxy is very big or very small, if you could sit on the *extreme edge* of its disk as it spins, it would take you about a billion years to go all the way round."
(emphasis mine)

While our sun is somewhat on the outskirts of our galaxy it's nowhere near the extreme edge.
granville583762
5 / 5 (3) Mar 16, 2018
Calculate the the orbital velocities of two stars around 7lys in 200milion years to counteract their gravitational force, there is no darkmatter.
makita:- Rotational curves of dark matter rich galaxies indicate, that the perimeter of galaxy rotates as a single body, like if the galaxy would be embedded inside of rigid jelly. It's nicely visible on http://cdn.theatl...323.jpg: the older galaxy on the left looks like being surrounded by invisible coat, along which the younger galaxy at the center of picture is sliding. Therefore the galaxies touching at distance would rotate like wheels in the gearbox. This effect could be therefore estimated from dark matter properties, which were known in 1933 already. But the truth remains, McCulloch has predicted it explicitly first in 2011.

granville583762
5 / 5 (3) Mar 16, 2018
this is the point size is irrelavent, its one orbital revolution of two stars, look up orbital mechanics
It was my understanding that our Milky Way rotated about once every 200 to 250 million years. So what gives?

antialias_physorg:- Our sun revolves around the galactic center every 200-250mn years. But not all parts of the galaxy rotate at the same speed. From the above article:
"But regardless of whether a galaxy is very big or very small, if you could sit on the *extreme edge* of its disk as it spins, it would take you about a billion years to go all the way round."
(emphasis mine)

While our sun is somewhat on the outskirts of our galaxy it's nowhere near the extreme edge.

Benni
1 / 5 (2) Mar 16, 2018
So, am I understanding correctly that the "years per rotation" of a star about its galactic centre is NOT the same for every distance from the centre? I thought that was the whole reason dark matter was invented, to explain why rotational periods of stars are the same regardless of radius from centre.


They have finally figured it out that there is no dark matter at the center of galaxies, the article was posted here a couple days ago, read it here:

https://phys.org/...ark.html
granville583762
5 / 5 (3) Mar 17, 2018
Exactly, no dark matter; its the orbital rotation of two stars of average 7Lrs apart to counter their gravition!

So, am I understanding correctly that the "years per rotation" of a star about its galactic centre is NOT the same for every distance from the centre? I thought that was the whole reason dark matter was invented, to explain why rotational periods of stars are the same regardless of radius from centre.


They have finally figured it out that there is no dark matter at the center of galaxies, the article was posted here a couple days ago, read it here:

https://phys.org/...ark.html


1 galactic rotation = 1 orbital rotation of 2 stars counteracts their gravity
granville583762
5 / 5 (3) Apr 08, 2018
i was waiting for some one to spot it 250million years
It was my understanding that our Milky Way rotated about once every 200 to 250 million years. So what gives?

Quote from link below:
"More mind-blowing is that this mass of stars, gas, planets and other objects are all spinning. Just like a pinwheel. It's spinning at 270 kilometers per second (168 miles per second) and takes about 200 million years to complete one rotation, according to the National Radio Astronomy Observatory. "

https://www.unive...otation/

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