Astronomers discover galaxy with no dark matter
The uncertainty of science: Astronomers have detected a galaxy about 250 million light years away that shows no evidence of any dark matter, a phenomenon that defies the accepted theories about dark matter.
The galaxy in question, AGC 114905, is about 250 million light-years away. It is classified as an ultra-diffuse dwarf galaxy, with the name ‘dwarf galaxy’ referring to its luminosity and not to its size. The galaxy is about the size of our own Milky Way but contains a thousand times fewer stars. The prevailing idea is that all galaxies, and certainly ultra-diffuse dwarf galaxies, can only exist if they are held together by dark matter.
Galaxy AGC 114905
The researchers collected data on the rotation of gas in AGC 114905 for 40 hours between July and October 2020 using the VLA telescope. Subsequently, they made a graph showing the distance of the gas from the center of the galaxy on the x-axis and the rotation speed of the gas on the y-axis. This is a standard way to reveal the presence of dark matter. The graph shows that the motions of the gas in AGC 114905 can be completely explained by just normal matter.
“This is, of course, what we thought and hoped for because it confirms our previous measurements,” says Pavel Mancera Piña. “But now the problem remains that the theory predicts that there must be dark matter in AGC 114905, but our observations say there isn’t. In fact, the difference between theory and observation is only getting bigger.”
The evidence for dark matter in almost all galaxies is the motion of gas and stars in the outer perimeter. Routinely they move faster than expected based merely on visible ordinary matter. To account for the faster speed, astronomers beginning in the late 1950s invented dark matter, an invisible material with a mass sufficient to increase the speeds of objects and gas in the outer regions of galaxies.
That increasingly astronomers are finding galaxies with no evidence of dark matter, based on rotation speeds, only makes this mystery all the more baffling.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The uncertainty of science: Astronomers have detected a galaxy about 250 million light years away that shows no evidence of any dark matter, a phenomenon that defies the accepted theories about dark matter.
The galaxy in question, AGC 114905, is about 250 million light-years away. It is classified as an ultra-diffuse dwarf galaxy, with the name ‘dwarf galaxy’ referring to its luminosity and not to its size. The galaxy is about the size of our own Milky Way but contains a thousand times fewer stars. The prevailing idea is that all galaxies, and certainly ultra-diffuse dwarf galaxies, can only exist if they are held together by dark matter.
Galaxy AGC 114905The researchers collected data on the rotation of gas in AGC 114905 for 40 hours between July and October 2020 using the VLA telescope. Subsequently, they made a graph showing the distance of the gas from the center of the galaxy on the x-axis and the rotation speed of the gas on the y-axis. This is a standard way to reveal the presence of dark matter. The graph shows that the motions of the gas in AGC 114905 can be completely explained by just normal matter.
“This is, of course, what we thought and hoped for because it confirms our previous measurements,” says Pavel Mancera Piña. “But now the problem remains that the theory predicts that there must be dark matter in AGC 114905, but our observations say there isn’t. In fact, the difference between theory and observation is only getting bigger.”
The evidence for dark matter in almost all galaxies is the motion of gas and stars in the outer perimeter. Routinely they move faster than expected based merely on visible ordinary matter. To account for the faster speed, astronomers beginning in the late 1950s invented dark matter, an invisible material with a mass sufficient to increase the speeds of objects and gas in the outer regions of galaxies.
That increasingly astronomers are finding galaxies with no evidence of dark matter, based on rotation speeds, only makes this mystery all the more baffling.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The mystery to me is that scientists are willing to invent, create or otherwise pull out of their hat an “explanation” for data that does not fit their model instead of looking harder at their model.
One would think that if they were to look to other branches of science such as sun modeling, climate modeling ….or
Oh never mind..
So no dark matter. Does that mean it is on the lighter side?
Go back through this guy’s posts:
https://physicsfromtheedge.blogspot.com/
He has alternative explanations that do not require Dark Matter.
You are right Chris,
Dark Matter is just a hypothesis. Historically it reminds me of the “Aether” that people once believed that the Earth and other celestial bodies traveled through. Remembering my physics, the Michelson-Morley experiment proved that the aether did not exist. I sure there will be another Michelson-Morley-like experiment to prove or disprove the existence of dark matter.
Dark matter is evidence of Iain M. Banks’ “sublimed” civilizations. :)
My comment is not whether Dark Matter exists or not – It is about the current state of science.
I get the strong feeling that through the government funding processes worldwide Science has adopted a Go-along-to-get-along attitude that creates the biggest and (in some eyes) the best of science. But often the biggest is build on a house of cards. I do not think this is the way of science – science is not a beauty pageant nor a fundraising campaign. As Prof. Mike Bright (Grove City College) once stated to me about engineering – a science: “It is the search for Truth.” Todays science seems to be a search for money, power, political power or some combination of the three.
Open, verified data, repeatable experiments (Not repeated ONLY if they can’t be repeated again – more scrutiny required here), open debate over theory, data, methods, results and non-partisan, non-outcomes based funding. This is science.
Good stuff, by all.
I’ll drop this in here— an excellent resource for homeschoolers.
The Mechanical Universe, Episode 41
“The Michelson Morley Experiment”
Caltech 1985
https://youtu.be/Ip_jdcA8fcw
28:46
“A series of 52 thirty-minute videos produced by Caltech covering the basic topics of an introductory university physics course.”
It has always been the issue with established science. They circle the wagons around the prevailing theories. Everyone know that gravity does not bend light. Everyone knows that the Earth is static and there is no such thing as plate tectonics. Everyone knows dinosaurs did not evolve into birds. Everyone knows CO2 is the leading cause of global warming (I mean climate change).
Until they are proven wrong over and over again.
The second you need some force that cannot be measured, cannot be seen, and cannot be experimented against, then you are in the realm of magic. If they find a way to measure it instead of just creating models, then they might actually have something.
Joe-
good stuff.
I’m reminded of “The Structures of Scientific Revolutions” by Thomas Kuhn.
(Had an entire class on that topic, and while not an actual techie-scientist per se, I was trained in (skinnerian) applied behavior analysis, and they drilled into my brain I wasn’t allowed to Appeal to Stuff we couldn’t actually get a grip on. I did adopt more cognitive methodologies later on, but I always try to remember — those most likely don’t actually represent the underlying mechanism in play. )
((The more ephemeral Stuff is very poetic, but it’s not really science, ya’ know?!))
Wayne,
That was an excellent series that played on PBS. I know many physics teachers, high school and college, that have used that series to compliment the lessons.
In defense of theoeretical physics, Pauli proposed the neutrino in 1930 to account for observed interactions. It took another 26 years to detect them. Although I do hve to admit I remain skeptical of dark matter and dark energy. It reminds of the shape of physics around the turn of the 20th century. It took relativity to solve those contradictions.
Could there be a super massive black hole increasing the gravity in that low population galaxy?
I sometimes just think they are calculating the expected gravity wrong.
If some galaxies have dark matter and some do not then it tends to refute those alternative formulations of the law of gravity as a way to model what we observe.
I had read a paper earlier claiming that gravitomagnetism (the analogue of magnetism for the gravitational force. I think it’s also called Lenz-Thirring or frame dragging force in other contexts/more complete GR treatments) can explain the increased rotation rate of stars attributed to dark matter, and also some other structural aspects of galaxies. I’m intrigued and it’s been on my to-do list to set up a simulation of this as soon as I can bash enough GPU code together to do that. If this is true, it could solve the mystery in a way that doesn’t require crazy amounts of invisible mass.
In special relativity, forces that act in one frame between stationary objects give rise to other forces acting between moving objects. In the SR context, magnetic fields *are* electric fields: The 3-d field vector is replaced with a 4-d tensor that acts on the world-line segment of a particle to bend its path. The resulting covariant equation is something like dv/dtau_j = F^ij * v_j The space-time components of the tensor are electric fields. The space-space components are magnetic fields. When transforming to a moving frame, the tensor tilts over and space-space components appear. I imagine soemthing similar happens with gravity in a weak-field limit – how I intend to simulate it.
Of course, if the rotation rate of the galaxies doesn’t correlate with the perceived dark-matter mass, then this model is busted. If the percieved dark matter mass varies independently of everything else, then it’s hard to escape the “something is there we can’t see” hypothesis. Will have to look into the statistics sometime.
You are correct MadRocketSci about the rotation rate of galaxies. Some parts of galaxies, like are our own are going the other direction due to the absorption of smaller galaxies. I was surprised to hear that finding when they deduced it from the data from the Gaia satellite.
Thank you for the comments, MadRocketSci. Things to consider.
So much for MONDS.
I don’t think anyone _likes_ dark matter, but it explains (in a vague, mysterious sort of way) the problems with current models.
I might be barking in the wrong tree.
How do they know the actual specific gravity of a galaxy?
They can measure the spin rate.
They can measure pretty accurately the diameter.
Can they detect and measure the expansion or contraction of the galaxy? This would effect the speed.
If they do not know the actual gravity in the galaxy how do they know whats to much or to little?
Thus the whole reason for dark matter.