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We Thought the Universe Was 13.8 Billion Years Old. We Were Wrong. - Video học tiếng Anh
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We Thought the Universe Was 13.8 Billion Years Old. We Were Wrong.
We Thought the Universe Was 13.8 Billion Years Old. We Were Wrong.
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Untertitel (202)
0:00
The night sky isn’t what you think it is. It’s not the beginning of time…
0:03
it’s a graveyard of light. The James Webb Space Telescope just sent
0:08
back images of thermal 'bruises' in deep space. Physical scars left behind by a universe that died
0:13
before ours was even born. The data doesn't just tweak the laws of physics... it sets them on fire.
0:19
And NASA is panicking. University of Kansas astronomer
0:23
Allison Kirkpatrick couldn't sleep. She had spent her professional career studying how galaxies
0:28
grow and evolve. But the first images from the James Webb Space Telescope, orJWST, left her
0:33
questioning everything she thought she knew. JWST is the most advanced and powerful space
0:39
telescope ever built. It was going to give astronomers and scientists a glimpse
0:43
into the past. A hint about how the first galaxies formed. Instead, it showed bright,
0:48
fully formed galaxies where there should have been darkness. They appeared in regions of the
0:53
universe that should have been practically empty. Back then, the cosmos was supposed to be a thin
0:58
fog of hydrogen and helium, slowly cooling and drifting, waiting for gravity to do its
1:03
work. But these images… they didn’t make sense. That primordial fog was expected to last for
1:09
hundreds of millions of years. Just floating in space. Long before any stars were born.
1:14
And those first celestial bodies should have burned out quickly and scattered the
1:18
ingredients for everything that followed. So the early universe, in theory, should
1:22
have been a blank canvas. JWST said differently.
1:26
The common assumption was that the universe followed one model: Lambda CDM. It’s the
1:31
standard story of the cosmos. A hot Big Bang, invisible dark matter pulling gas into clumps,
1:36
and dark energy driving everything apart faster and faster. For years, the data backed it up. The
1:42
universe was 13.8 billion years old. Or so we thought.
1:46
The first full color Webb image landed in July 2022, showing a galaxy cluster
1:51
called SMACS 0723. Immediately, something was wrong. There were too many galaxies. They were
1:59
too bright. They shouldn’t have been there. Research papers were thrown out, consigned
2:04
to trash cans. If the images were accurate, then the timeline of early galaxies was wrong.
2:09
The old galaxy consensus was dead. A faint smudge in the Boötes
2:14
constellation was the prime suspect. Its catalog name is CEERS-93316 and its first
2:22
measurement suggested it was seen at a redshift of 16.7. It was a number that raised eyebrows.
2:28
Redshift is essentially a time machine built into the fabric of the universe.
2:32
As space expands, it stretches the light traveling through it, pulling it toward the red end of the
2:38
spectrum. The more stretched that light is, the further back in time it comes from. Eventually,
2:43
looking deeper into redshift feels less like looking farther away,
2:46
and more like watching earlier and earlier versions of the universe play out in reverse.
2:51
At a redshift of 16.7, this object would sit about 235 million years after the Big
2:57
Bang. It’s an era where almost nothing this large should have had time to form.
3:02
Think of the entire universe as a huge building site. A crew has just broken ground on an empty
3:07
lot. Five minutes later, you take a photo, and in the middle of the lot is a finished
3:12
100 story tower. The lights are on and a hive of activity. There hasn’t been enough time to
3:17
build something like this. And yet… there it is.
3:20
In JWST’s near-infrared images, the galaxy looked exactly like that kind of anomaly.
3:26
For a moment, it fit the profile of something from the early universe.
3:30
Then that argument began to fall apart. That 16.7 was a quick estimate, pulled from the
3:36
galaxy’s color across a handful of broad filters. It was more of a first guess than a verdict.
3:41
So the team went back and ran it through JWST’s spectrograph, an instrument that reads light in
3:46
detail. The result changed everything. The extreme distance disappeared. The true redshift was 4.9,
3:53
an ordinary galaxy, about 1.2 billion years old. What had looked like a cosmic record-breaker
3:58
turned out to be a trick of alignment. At just the right distance, a hydrogen emission line
4:03
slid neatly into 3 of the reddest filters, while a set of oxygen lines boosted a 4. It lit up in a
4:10
handful of bands, went dark in the rest, and mimicked something far older than it really was.
4:15
The most distant object ever seen was a mirage. But not every galaxy collapsed under closer
4:21
scrutiny. Some held up completely. By 2024, dozens of early galaxies had been checked, and most were
4:28
where their first color estimates suggested. Only a few, like the Boötes smudge, turned out to be
4:33
impostors. The real early galaxies tend to be smaller and dimmer, but they survived every test.
4:39
So the early universe isn’t an illusion. It’s just harder to read than it first appears.
4:44
But one problem still refuses to go away. And it’s worse than anyone thought.
4:49
Adam Riess, a Nobel Prize winner, studies how fast the universe is expanding right now. His
4:54
team builds what’s called a cosmic distance ladder. It’s a way of measuring across space
4:59
using known, repeating cosmic signals as stepping stones. And it’s caused a
5:03
problem scientists now call the Hubble Tension. Riess and his team used their model and arrived
5:08
at a number, 73. But there’s another way to read the universe. Instead of looking at nearby space,
5:14
it starts with the oldest light we can see: a faint afterglow from when the universe was just
5:19
380,000 years old. It’s a frozen snapshot of the early cosmos, before stars and galaxies existed.
5:26
If you take that starting point and run the universe forward using the standard model,
5:32
you don’t get 73. You get about 67. Those two numbers should match.
5:37
They don't. The gap between them
5:39
has now reached what scientists call 5 sigma. It’s a way of saying the difference is so large that,
5:44
if nothing is wrong, it would almost never appear by chance. In practical terms,
5:49
it’s about 1 in 3.5 million. That's almost 3 times rarer than getting struck by lightning.
5:54
At first, people assumed it had to be an error in the cosmic ladder. But JWST looked again.
6:00
There was no error. Riess used JWST to
6:03
recheck over 1,000 of his stars. The distances barely moved. His ladder held.
6:09
Not everyone agrees on where the problem lies. Wendy Freedman, an astronomer at the University
6:13
of Chicago, approached the question using a completely different method. Instead of
6:17
relying on the same cosmic distance ladder, she used a special class of red giant stars
6:22
as guides. Her result came in around 70, right between the two competing answers.
6:27
That matters because it suggests the Hubble Tension might not be as simple as one side
6:32
being right and the other wrong. The trouble is that no explanation
6:36
has managed to satisfy everyone. One of the leading ideas is something
6:40
called early dark energy, a brief burst of extra energy that may have altered the
6:44
universe’s expansion shortly after the Big Bang. If something like that happened, it could help
6:49
explain the conflicting measurements. Projects such as the Dark Energy Spectroscopic Instrument,
6:54
or DESI, is surveying tens of millions of galaxies, searching for evidence that the
6:59
universe once expanded differently than we think. Maybe one set of measurements still contains a
7:03
hidden flaw. Maybe dark energy has changed over time. Or maybe the standard model of
7:08
the universe is missing a piece entirely. What makes the Hubble Tension so unsettling
7:13
is that it goes beyond the usual explanation. Earlier anomalies often faded under a closer
7:19
look. A galaxy that seemed distant turned out to be closer. A strange signal turned out to be
7:24
misleading. The mystery shrunk. This one didn't.
7:27
It’s a difference between the universe we see today and the universe our best model
7:31
predicts. The more precisely anyone measures it, the harder that difference becomes to
7:36
In 2023, Ivo Labbé and his team published a paper highlighting 6 objects that shouldn’t
7:42
have existed. We’re seeing them 500 to 700 million years after the Big Bang,
7:47
when the universe was still in its infancy. Yet they already looked like fully grown galaxies.
7:52
The problem was their size. By some estimates, they had 10 to 100
7:56
times more mass than models said was possible. A few appeared to rival 100 billion Suns, all packed
8:03
into regions smaller than the Milky Way. If those first measurements were right,
8:07
astronomers had a serious problem. There simply hadn't been enough time for these galaxies to
8:12
build that many stars. The numbers didn't add up. So the investigation started over. And as better
8:17
data came in, the impossible began to shrink. Astronomers called them little red dots.
8:23
JWST wasn't finding just one or two. It was spotting them everywhere it looked. When
8:28
researchers studied their light more closely, they noticed something strange. Instead of the
8:32
clean signature you'd expect from a normal galaxy, the light showed wide, smeared emission lines. It
8:38
was a telltale sign that gas was whipping around a black hole at incredible speeds.
8:43
That changed everything A lot of these objects seem to hide
8:46
black holes weighing millions - or even hundreds of millions - of Suns behind thick clouds of dust.
8:53
That's important. Black holes can be unbelievably bright. Bright enough to fool us into thinking
8:58
we're seeing far more stars than are really there. One of the earliest candidates looked almost as
9:03
big as the Milky Way. Our galaxy took more than 13 billion years to build up that much
9:08
mass. This object seemed to have done it in just a few hundred million years.
9:12
That's what made astronomers wonder if they were looking at something else entirely.
9:16
One possibility is something called a black hole star: a black hole buried inside a thick cocoon
9:22
of gas. From billions of light-years away, it can look like a single enormous star. If they exist,
9:28
JWST might just have found the first one. But there's still a problem.
9:32
The early universe didn't have that much material to work with.
9:36
Most of the ordinary matter was still floating around as gas, not locked up in stars.
9:41
To get that massive so quickly, these galaxies would have had to pull off something never
9:45
seen before. Almost every bit of available gas would need to become stars. Then it would have
9:50
to squeeze into one small space It seemed impossible.
9:54
But there was another issue. Some of these little red dots
9:57
are surprisingly faint in X-rays. Active black holes usually shine brightly in X-rays. It just
10:03
added to the mystery. Some of the little red dots could be dust-shrouded black holes. Some could be
10:08
something else completely. But the idea that these were massive galaxies was fading fast.
10:13
It’s more like that astronomers were counting the wrong light.
10:17
But what if the galaxies aren't the problem? Physicist Rajendra Gupta proposed a much more
10:22
radical answer. Maybe those galaxies only look old because the universe
10:25
itself is older than we think. His model, called CCC+TL,
10:30
moves the age of the universe from 13.8 billion years to roughly 26.7 billion.
10:36
That would give the cosmos almost twice as much time to build galaxies, stars, and black holes.
10:42
Suddenly those early galaxies don't look so impossible.
10:45
To get there, Gupta combined two controversial ideas. The first allowed some of nature's
10:50
fundamental constants to slowly change over time. The second updates a theory called tired light.
10:56
This is where photons gradually lose energy as they travel across the universe. Distant
11:00
galaxies look redder not because space expanded, but because their light faded during the journey.
11:06
It sounds plausible. But most physicists aren't convinced.
11:10
Gupta published the idea in a peer-reviewed journal in 2023, and other researchers quickly
11:15
responded. Their argument was simple: the model clashes with too much existing evidence.
11:19
It struggles to address the cosmic microwave background, the leftover glow of the Big Bang.
11:25
There's a bigger issue. The trouble is that tired light
11:28
has been around for a long time. And every time astronomers have put it to the test,
11:32
it comes up short. If the universe is expanding, distant galaxies should look redder, dimmer,
11:37
and stretched in specific ways. That's exactly what we see. Tired light can explain
11:42
the reddening, but it doesn’t explain rest. So while it's a good attempt to solve the mystery,
11:47
most astronomers don't think it's the answer. But what if the issue was the big bang?
11:52
If anyone gets to propose a radical idea about the universe, it's Roger Penrose. He's one of
11:57
the world's leading experts on black holes and won a Nobel Prize for his work. His idea is
12:01
called Conformal Cyclic Cosmology, or CCC. And it starts with a simple question:
12:07
what if the Big Bang wasn't the beginning? According to Penrose, the universe goes
12:11
through endless cycles. One age ends, another begins. It’s a cycle that goes on and one.
12:16
Imagine fast-forwarding trillions upon trillions of years into the future.
12:20
Every star has burned out and matter has decayed. Even the last black holes have evaporated away.
12:26
Everything is gone. Penrose argues that at that point,
12:29
the difference between infinitely large and infinitely small starts to lose its meaning.
12:34
And if that's true, the end of one universe could become the beginning of the next.
12:38
In other words, the Big Bang might not have been a beginning at all. It could have been the end
12:43
of a universe that existed before ours. Penrose has even gone a step further.
12:48
He proposed a hypothetical dark matter particle called an erebon. If these particles exist,
12:54
they could leave faint traces in the sky that future telescopes might be able to spot.
12:58
But there's a catch. For this to work, the future of the universe has to behave in ways we've never
13:03
observed. That's why most cosmologists see CCC as an interesting possibility rather than a
13:09
definitive explanation. It's a bold idea.
13:12
The question is whether nature agrees. Penrose claims his theory can be tested.
13:17
He believes his cyclic universe left real evidence and we’ve already captured it.
13:22
According to his theory, the universe before ours contained enormous black holes. Over time,
13:27
those black holes evaporated away. In Penrose's model, the final burst of
13:31
energy from each one crossed the boundary between cosmic cycles and left an imprint on our universe.
13:38
A fingerprint of a dead universe. Where would you look for that fingerprint?
13:42
In the oldest light we can see… the cosmic microwave background. It’s the
13:47
faint afterglow of the Big Bang that fills the entire sky. Penrose and his
13:51
team argue that some regions are warmer than they should be. Not random specks,
13:56
but circular patches roughly 8 times wider than the full Moon.
14:00
In a 2020 paper, the team reported finding these circles in data from both the Planck
14:04
and WMAP satellites. They called them Hawking Points. And if their interpretation is correct,
14:10
these aren't just random features. They're relics from giant black holes
14:15
that existed before our universe was born. Other researchers examined the same maps and
14:20
reached a different conclusion. When they reran the analysis, the signal became much
14:24
less impressive. The problem is that if you search a huge dataset for unusual patterns,
14:29
you'll almost always find some. Think about spotting shapes in
14:32
clouds. If you start looking for circles, after a while, it’s easy to find them.
14:36
So, are these real scars from a universe before ours…or just patterns hiding in the noise?
14:43
Either way, it sets the stage for an academic civil war.
14:46
Researchers are working toward one of the biggest questions in science: how the universe began.
14:51
Careers, grants, and scientific reputations all hinge on getting that answer right. The stakes
14:56
feel personal because they are. And right now, that search
14:59
is playing out in real time. In journals and at conferences,
15:03
teams are arguing over JWST’s earliest galaxy candidates. Whether they really
15:08
are as massive and distant as they first appear, or whether effects like cosmic debris are making
15:14
them look more extreme than they truly are. But this isn’t just about distant galaxies,
15:18
it’s also about our place in it. Look down at your hands. Every atom in
15:23
them was forged inside ancient stars. In some versions of cyclic cosmology, even the light
15:29
around you might not be new in a cosmic sense. It’s just recycled from an earlier universe.
15:35
So where does that actually leave us? Not with a broken Big Bang.
15:40
The basic story surrounding it still holds. The universe is expanding, and if you run
15:44
the clock backwards, everything points to a hot, dense beginning. It’s written into the
15:49
simplest elements in space: hydrogen and helium still appear in exactly the amounts the theory
15:54
predicts. When everything is added up, the age of the universe is still around 13.8 billion years.
16:00
New surveys are already pushing deeper into the early universe, and those little red dots
16:05
may change how we think galaxies first formed. What ever JWST finds, this isn’t a crisis in
16:11
cosmology, but a picture of the universe that’s still being filled in, one piece at a time.
16:16
It looks like the James Webb Space Telescope has just uncovered another mystery… and it’s
16:21
not the only one hiding out there. If you want to go deeper, watch “50 Surprising Facts About Space
16:26
You Didn't Know” to see what else the universe is keeping from us. Or click on this video.
