Astronomy Is In Crisis...And It's Incredibly Exciting
Astronomy Is In Crisis...And It's Incredibly Exciting
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0:00Now’s the perfect time to grab the 12,026
calendar – and get it in time for the holidays.
0:06Our best theory of the universe
could be wrong – finally.
0:10We’re going through an incredibly exciting moment.
0:13Thanks to amazing new technology,
0:16our understanding of the universe is
moving faster than it has in years.
0:20And if we are fortunate, we could be at the
edge of the next revolution in the way we see
0:25the cosmos – a moment as exciting as when we first
realized that the Earth revolves around the Sun,
0:31that the stars are other suns, or that our galaxy
is just one tiny island in an ocean of trillions.
0:39Why do we think this?
0:41Because for the first time in ages,
the universe is misbehaving.
0:45Badly.
0:46Nasty Universe
0:49For decades, we’ve had a
beautiful theory of the cosmos.
0:52One that explained how the universe began, what
it’s made of, and how it’s supposed to behave.
0:57It matched our observations astonishingly well and
1:00made us feel like we’d almost
deciphered the cosmic code.
1:04But in the last few years,
1:05as our telescopes got better and our
data sharper, cracks started to appear.
1:10Strange mismatches between what the
theory predicted and what we actually saw.
1:15At first they looked like silly mistakes,
noise that would go away with more data.
1:21But as new data came in, the opposite happened.
1:24Some cracks got larger, new ones emerged,
1:27and our once perfect picture of the cosmos
began to look less and less … perfect.
1:33Of course, this wasn’t new.
1:35Two centuries ago, astronomers noticed that
1:37Uranus’ orbit didn’t quite
follow the laws of gravity.
1:41But instead of throwing those laws away,
1:43they proposed that a “dark planet”
was tugging on Uranus from afar.
1:47Shortly after, Neptune was discovered –
exactly where the math said it would be.
1:52But then came Mercury.
1:54Its orbit also didn’t make sense,
so scientists tried the same trick.
1:58But this time, no new planet showed up.
2:01The answer wasn’t more stuff,
but a completely new idea.
2:04Gravity had to be reimagined, and we
invented general relativity – opening
2:09a whole new dimension in our
understanding of the universe.
2:12So are we going through a
Uranus moment or a Mercury one?
2:17First Crack – Cosmic Monsters
2:20The first signs that something deep
could be off began piling up around
2:2415 years ago – in the form of a few
seemingly impossible cosmic monsters:
2:29A “giant arc” of galaxies over
3 billion light-years wide.
2:34A massive group of quasars
spanning 4 billion light-years.
2:38A ring of galaxies 5 billion light-years across.
2:41An unfathomable wall of galaxies
stretching ten billion light-years
2:45from end to end – a whopping 10%
of the entire observable universe.
2:51The list goes on.
2:52That’s not all.
2:53There are also monstrous voids:
2:56vast cosmic deserts with far
fewer galaxies than normal.
2:59And according to some surveys, we
happen to be living deep inside
3:03one of them – a gargantuan “local
hole” 2 billion light-years across.
3:08Where’s the problem?
3:10Well, the universe is organized
in ever larger structures:
3:13galaxies, galaxy clusters,
superclusters and eventually
3:17filaments – truly gargantuan structures
separated by equally enormous voids.
3:22But our cosmic theory says that these
things can’t get arbitrarily large.
3:27At distances beyond one billion light-years or so,
3:30the filaments and voids should
blur into a uniform soup.
3:33And this is more than a technical detail – it’s
3:36a basic pillar of all our attempts
to make sense of the cosmos itself.
3:40Our understanding of the universe
rests on one key assumption:
3:44the cosmological principle.
3:46This is the idea that, if you zoom out far enough,
3:49the universe should be uniform,
looking the same everywhere.
3:52This is crucial because it means that our limited
view of the cosmos is a fair sample of the whole.
3:58That, even if we are tiny creatures
living in a speck of dust,
4:01we can learn things about the entire universe.
4:05Both the cosmos itself and our place in it might
be more unruly and chaotic than they should be.
4:11But if the cosmological principle turns
out to be wrong, we have a huge problem.
4:16Because if the universe isn’t the same everywhere,
4:19we could be like ants trying to guess the flavor
of a cake while sitting on its only cherry.
4:24Everything we see might just
be local weirdness – a cosmic
4:28quirk that doesn’t tell us the
actual story of the universe.
4:32Second Crack – A Universe at Two Speeds
4:36The next crack appeared about 10 years ago.
4:38It tore straight at the fabric of
space – challenging how fast it grows.
4:43Every second the universe gets a little bigger.
4:46We know this because we have
different ways to measure it
4:48and all confirm that space is expanding.
4:51The problem? They can’t agree on how fast.
4:55It’s like measuring the speed of a car using
two devices and getting different results.
4:59You read 67 on the speedometer, but 73 on the GPS.
5:03One of the instruments must be broken, right?
5:06But then you check them again and again
and again… and both work flawlessly.
5:12This is very much what happens with the universe.
5:14The details are messy and complicated,
but they don’t matter for this story.
5:18The important part is that, as measurements and
calculations have become more and more precise,
5:23the disagreement has only become worse.
5:26By now, the chance that this mismatch is just an
accidental fluke is less than one in a million.
5:32The universe is literally giving us two
different answers to the same question.
5:37So something fundamental must be broken –
either our measurements of the universe,
5:42or our basic understanding of it.
5:45Third Crack – Old Galaxies in a Baby Universe
5:49The latest surprise is only about 3 years old.
5:52It shattered a key part of our cosmic timeline
– how and when the first galaxies formed.
5:58Telescopes act like time machines.
6:00Light from distant galaxies takes so long to reach us
6:03that we don’t see them as they are
now, but as they were in the past.
6:07In 2021 we launched the James Webb, the
most powerful space telescope ever built.
6:12And almost immediately, it began finding bright,
6:15massive galaxies so distant that they belong to
a time when the universe was extremely young.
6:21The problem?
6:22Some are so premature that they date back to 280
6:26million years after the Big Bang –
far earlier than anyone expected.
6:30Our theory says that the amorphous soup
of matter that emerged from the Big Bang
6:34gave rise to the first galaxies
through a long chain of mergers.
6:37Tiny lumps of dark and normal
matter gathered under gravity,
6:41building larger chunks that then
fused into even bigger ones and so on.
6:45But this process is lengthy.
6:47By our best estimates, the
first large galaxies should
6:50have emerged 500 million years after
the Big Bang or so, not much before.
6:55But it isn’t only that we’ve found
large galaxies existing way before that.
6:59The new galaxies also seem to be too mature.
7:03Matter in the baby universe was made up
almost entirely of hydrogen and helium.
7:07Heavy elements like carbon or nitrogen were
only forged later in the cores of stars,
7:12which had to explode to release them.
7:14But some of these super early galaxies
contain a lot of heavy elements – meaning
7:18that entire generations of stars must
have lived and died even before them.
7:23So this is like finding
grown-up kids in a kindergarten.
7:26Either the first galaxies
sprouted in fast forwards,
7:29or we are missing something huge
about the infancy of the universe.
7:33From Cracks to Crisis
7:36These problems aren’t the only ones.
7:38Our theory also says that the Big Bang
should have created 3 times more lithium
7:42than we see out there – a decades-old
itch that astronomers just can’t scratch.
7:47It predicts that dark matter should
pile up sharply at galaxy centers,
7:51but instead we find gentle hills.
7:53It says that dark energy, the mysterious
force pushing the universe apart,
7:57has stayed constant since the Big Bang.
7:59But last year, one of the
biggest galaxy surveys ever
8:02conducted dropped the bombshell that
it may have been changing over time.
8:06If true, this would overturn our current picture
of the universe, its past and its future.
8:12Even things that we considered
settled beyond any doubt,
8:15like the interpretation of the cosmic
microwave background, are suddenly up
8:18for debate – those early galaxies might have
been bright enough to contaminate the signal.
8:23These are bold claims that
require much more evidence.
8:26But the mere fact that such fundamental
pillars are being discussed is staggering.
8:30So ok – what does all this mean?
8:34Right now there are furious battles going on.
8:37Some scientists argue that
these aren’t real cracks,
8:39but mirages that will disappear with time, or
raw gems that will end up refining our theories.
8:45Others are more radical and say
we need completely new ideas.
8:49But whatever the case, the big picture is
8:52difficult to ignore – the
sense of crisis is growing.
8:55And for the first time in ages,
8:57we don’t really know what cosmology
will look like when the dust settles.
9:01Which is amazing.
9:02Because in science, “crisis” doesn’t mean failure.
9:05It means that the machine is healthy and working.
9:09Science doesn’t move in a straight line,
9:11but in cycles – periods of
calm followed by sudden crises.
9:15When a crisis hits, experiments start giving
results that don’t fit existing theories,
9:20confusion grows, and strange ideas pop up.
9:23And eventually, there is a revolution.
9:26A deeper truth emerges, and a
new cycle starts over again.
9:30The universe is screaming
that our story is incomplete.
9:35Whether we’ll find a cosmic
Neptune or a cosmic Mercury,
9:38one thing is certain – the cosmos is
about to get a lot more interesting.
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