A 'Hubble Crisis'? New Measurement Confirms Universe is Expanding Too Fast for Current Models (phys.org) 30
"The universe is expanding faster than predicted by theoretical models," writes Phys.org, "and faster than can be explained by our current understanding of physics." There's now been new confirmation of this (published in The Astrophysical Journal Letters) by a team led by Dan Scolnic, an associate professor of physics at Duke University.
And this means the so-called Hubble tension "now turns into a crisis," said Dan Scolnic, who led the research team... This is saying, to some respect, that our model of cosmology might be broken." Measuring the universe requires a cosmic ladder, which is a succession of methods used to measure the distances to celestial objects, with each method, or "rung," relying on the previous for calibration. The ladder used by Scolnic was created by a separate team using data from the Dark Energy Spectroscopic Instrument (DESI), which is observing more than 100,000 galaxies every night from its vantage point at the Kitt Peak National Observatory. Scolnic recognized that this ladder could be anchored closer to Earth with a more precise distance to the Coma Cluster, one of the galaxy clusters nearest to us. "The DESI collaboration did the really hard part, their ladder was missing the first rung," said Scolnic. "I knew how to get it, and I knew that that would give us one of the most precise measurements of the Hubble constant we could get, so when their paper came out, I dropped absolutely everything and worked on this non-stop."
To get a precise distance to the Coma cluster, Scolnic and his collaborators used the light curves from 12 Type Ia supernovae within the cluster. Just like candles lighting a dark path, Type Ia supernovae have a predictable luminosity that correlates to their distance, making them reliable objects for distance calculations. The team arrived at a distance of about 320 million light-years, nearly in the center of the range of distances reported across 40 years of previous studies — a reassuring sign of its accuracy. "This measurement isn't biased by how we think the Hubble tension story will end," said Scolnic. "This cluster is in our backyard, it has been measured long before anyone knew how important it was going to be."
The results? "It matches the universe's expansion rate as other teams have recently measured it," writes Phys.org, "but not as our current understanding of physics predicts it. The longstanding question is: is the flaw in the measurements or in the models? Scolnic's team's new results add tremendous support to the emerging picture that the root of the Hubble tension lies in the models..."
And the article closes with this quote from Scolnic: "Ultimately, even though we're swapping out so many of the pieces, we all still get a very similar number. So, for me, this is as good of a confirmation as it's ever gotten. We're at a point where we're pressing really hard against the models we've been using for two and a half decades, and we're seeing that things aren't matching up," said Scolnic.
"This may be reshaping how we think about the universe, and it's exciting! There are still surprises left in cosmology, and who knows what discoveries will come next?"
And this means the so-called Hubble tension "now turns into a crisis," said Dan Scolnic, who led the research team... This is saying, to some respect, that our model of cosmology might be broken." Measuring the universe requires a cosmic ladder, which is a succession of methods used to measure the distances to celestial objects, with each method, or "rung," relying on the previous for calibration. The ladder used by Scolnic was created by a separate team using data from the Dark Energy Spectroscopic Instrument (DESI), which is observing more than 100,000 galaxies every night from its vantage point at the Kitt Peak National Observatory. Scolnic recognized that this ladder could be anchored closer to Earth with a more precise distance to the Coma Cluster, one of the galaxy clusters nearest to us. "The DESI collaboration did the really hard part, their ladder was missing the first rung," said Scolnic. "I knew how to get it, and I knew that that would give us one of the most precise measurements of the Hubble constant we could get, so when their paper came out, I dropped absolutely everything and worked on this non-stop."
To get a precise distance to the Coma cluster, Scolnic and his collaborators used the light curves from 12 Type Ia supernovae within the cluster. Just like candles lighting a dark path, Type Ia supernovae have a predictable luminosity that correlates to their distance, making them reliable objects for distance calculations. The team arrived at a distance of about 320 million light-years, nearly in the center of the range of distances reported across 40 years of previous studies — a reassuring sign of its accuracy. "This measurement isn't biased by how we think the Hubble tension story will end," said Scolnic. "This cluster is in our backyard, it has been measured long before anyone knew how important it was going to be."
The results? "It matches the universe's expansion rate as other teams have recently measured it," writes Phys.org, "but not as our current understanding of physics predicts it. The longstanding question is: is the flaw in the measurements or in the models? Scolnic's team's new results add tremendous support to the emerging picture that the root of the Hubble tension lies in the models..."
And the article closes with this quote from Scolnic: "Ultimately, even though we're swapping out so many of the pieces, we all still get a very similar number. So, for me, this is as good of a confirmation as it's ever gotten. We're at a point where we're pressing really hard against the models we've been using for two and a half decades, and we're seeing that things aren't matching up," said Scolnic.
"This may be reshaping how we think about the universe, and it's exciting! There are still surprises left in cosmology, and who knows what discoveries will come next?"
Re:I have a theory .. (Score:5, Insightful)
Re:I have a theory too (Score:2)
I have a theory .. the expansion is caused by surface tension on a hyper-dimensional bubble.
My theory is that there are an infinite number of leprechauns pushing at the edge of the universe. As the size of the universe increases, the resistance becomes less and the leprechauns are thus able to increase the speed of expansion.
In plain English (Score:5, Insightful)
Okay, if I understand the completely click-bait, topsy-turvy article writeup, the situation is this:
The current best guess for the expansion of the universe (by the Hubble constant) is not predicted by current models.
Astrophysicists were wondering if the flaw was in the models or the measurement methods. The current experiment shows that the measurement methods are accurate, indicating that it's the model that's wrong.
The universe is expanding. If you tally up all the gravitational attraction in the universe, you would expect the universe to expand, slow down, stop, and then collapse back into itself. (Or slow down less and less over time, reaching zero expansion in infinite time.)
However, the expansion is increasing over time. There is no explanation for this, so we assume "dark energy" is somehow involved.
This is different from "dark matter" that seems to show up in galaxies. About 83% of all matter in some galaxies (including our own) is dark matter, but about 70% of all matter in the universe is dark energy. Of the remaining 30%, 83% is dark matter in the galaxies, and 17% (of the 30%) is regular matter.
Re:In plain English (Score:5, Funny)
Re: (Score:3)
Re: (Score:2)
The velocity factor (VF),[1] also called wave propagation speed or velocity of propagation (VoP or vP) of a transmission medium is the ratio of the speed at which a wavefront (of an electromagnetic signal, a radio signal, a light pulse in an optical fibre or a change of the electrical voltage on a copper wire) passes through the medium, to the speed of light in vacuum. For optical signals, the velocity factor is the reciprocal of the refractive index.
The speed of radio signals in vacuum, for example, is the
Re:In plain English (Score:5, Insightful)
In plain English, when we accumulate data, our perception of the world can shift dramatically.
Examples:
1. Once enough data was accumulated, our view of the world changed from geocentric to heliocentric. ...
2. Once enough data was accumulated, our view of the world changed from one built on mathematical idealizations to one built on some "uglier things", like ellipses.
3. Once enough data was accumulated, our view of the world changed again, and we understood why these kinematic rules apply. Incidentally, we were able to explain nearly all things we saw, for a while
4. When our observations improved even more, we suddenly realized our world is a lot bigger than we thought.
5. When our observations improved further, we saw evidence that our ideas of "space" and "time" may not be valid when times are short and speeds are high
6. When our observations improved further, we saw that gravity can produce strange effect on space and time on its own
7.
You get the idea. This is more of the same. But don't worry, whatever we discover in the future will not impact the things we know already at the scales we know them. Just like quantum mechanics didn't make the rainbow vanish, or like Einsteinian interpretation didn't make falling off the 5th floor any different.
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
They'll figure this out eventually, but the secret is that gravitational attraction simply shuts off past a certain distance. That's the only real flaw in their current model, it obviates the need for "dark" stuff, and it's a fair mistake to make, because it isn't logically contiguous with how everything else works. Once they find the formula for the max distance of gravitational attraction it will make the rest of the model work.
The aliens will punish me for posting this.
Re: (Score:3)
the secret is that gravitational attraction simply shuts off past a certain distance
"Certain distance" measured from which point?
Re: (Score:2)
Re: (Score:3)
I know what he's talking about, but he doesn't.
The MOND theories I've had the patience to check out are exercises in math that have no reasonable physics behind them.
As a result, they tend to take on just pieces of the problem and ignore any evidence that doesn't fit.
So, not holding my breath about any one of them replacing Newtonian gravity.
Re: In plain English (Score:2)
My pet hypothesis, based on a physics lecture I saw by a bona fide physicist at MIT, reference unfortunately lost, is that the red shift measurements are "wrong" because don't subtract out rotational forces
Re: (Score:2)
They'll figure this out eventually, but the secret is that gravitational attraction simply shuts off past a certain distance. That's the only real flaw in their current model, it obviates the need for "dark" stuff, and it's a fair mistake to make, because it isn't logically contiguous with how everything else works. Once they find the formula for the max distance of gravitational attraction it will make the rest of the model work.
Unfortunately, to explain away dark matter you need exactly the opposite: you need to say gravity doesn't drop toward zero past a certain distance.
This is how the MOND type theories work: suggesting that gravity gets stronger than expected at very very large distances.
The aliens will punish me for posting this.
No, but the people who pay attention to modern physics will.
Re: (Score:2)
Crisis? What Crisis? (Score:3)
Just get Congress to write legislation that says creation was in 4004BC and the incoming president will sign it.
Problem solved.
Re: (Score:2)
404 BC, universe beginning not found
The no fun chewing gum ... (Score:2)
Hubble Bubble -- the bubbles expand too fast.
(Note: The Pink flavor is discontinued 'cause of Red Dye #3.)
Flat-Earthers (Score:2)
...will have a great day when they hear about it.
someone smarter than me.... (Score:1)
...can explain how we have such confidence that "Type Ia supernovae have a predictable luminosity that correlates to their distance, making them reliable objects for distance calculations"?
It seems a great deal hinges on this assumption.
I understand that observed ones fit relatively well on a curve when we correct for luminosity but
A) not THAT perfectly
B) we haven't observed that many in stellar scales
C) even if it is a good "general rule" that makes it even more vulnerable to exceptions and frankly in gala
Crisis! (Score:1)
Oh, wait, it's just a scientific curiosity for us to learn from.
Ah (Score:1)