Astronomers Find Invisible Galaxies That Change Everything We Know About Science


Ok, so here’s some space 101 for you. You know what a planet is, right? You’re sitting on one at this moment in
time. It’s Earth, your home. We are the third rock from the sun. The first is Mercury, ‘cos he’s closest
to that energy giver, the Sun. Our family is called the Solar System. The planets, dust, rocks, moons, asteroids,
are all in this family. But that’s just one Sun, and it is part
of what you could call an extended family, which is called a galaxy. Our galaxy is called the Milky Way, which
is kind of cute. It consists of maybe 200 – 400 billion stars
and maybe perhaps in the region of 800 billion planets. Some planets are star-less, orphans, and they
are called rogue planets. We apologize if you are now groaning and saying,
“C’mon, everyone knows that,” but if you didn’t know and we told you today’s
story it wouldn’t really make any sense. You might have been surprised to hear that
we said there are maybe 200 – 400 billion stars in our galaxy and maybe 100 – 200
billion galaxies altogether in the entire universe. Well, you might also read two trillion galaxies,
but we’ll talk about that later. In just the Milky Way there could be 100 billion
planets, or as we said 800 billion. The numbers keep changing. Talk about an inexact science, surely astronomers
can do better than that? Well, not really, but they are already doing
a pretty impressive job. To understand what they are working with you
have to first understand how big things are. Before you think they should do a better job,
imagine standing at the top of a mountain and then being told to count all the ants
in the world around you. You couldn’t, and astronomers simply can’t
count everything in this universe. They make informed guesses based on what they
do know and then extrapolate, something you could probably do with your ant-counting conundrum. The universe, er, is big. We guess you know that, but do you know how
big? The nearest galaxy to ours is called the Andromeda
Galaxy, and that in terms of the bigger picture is just down the street. It’s our closest neighbor, our bosom-bigger-buddy. If our galaxy wanted to borrow some milk,
it would just pop around to Andromeda. But it’s actually 2.537 million light years
away. A light year is the distance light travels
in a year. That means if we travelled at the speed of
light, which is approximately 186,000 miles per second (300,000 km per second), it would
take us 2.537 million years to get there, and that’s our next-door neighbor. Consider that the fastest any human has ever
travelled was inside that old clunker Apollo 10, and that chugged along at 24,790 mph (39,897km/h). One day apparently the Milky Way and Andromeda
will hook-up, according to astronomers. They will merge, but that love story won’t
be completed for quite a few billion years so don’t go getting excited just yet. But as it’s getting closer some people say
if we sent a probe there now it might reach Andromeda in a mere 3.9 billion years. We hope now you understand just what astronomers
are working with. That’s why the numbers are not accurate,
the dammed universe is just too big to observe with any clarity, especially once we start
looking further afield. So NASA tells us our Milky Way might have
200 billion stars, or it might have 400 billion stars. Most experts tell us that to the visible eye
here on Earth at best you could probably count 5,000 stars. Go out to the desert and give it go. We recommend it as a sleep aid, or an exercise
in making you feel humble down here on our blessed rock. But we have toys, and those toys help us to
see further. You don’t have a chance standing on that
mountain in North America counting ants in a garden far, far away, but NASA has the Hubble
Space Telescope and it is pretty amazing. It can do things like look at a patch of space
for 10 whole years and it will come up with an image which is called the Hubble eXtreme
Deep Field. So, what was the outcome of this image? Thousands of galaxies were revealed, and they
were in the deepest reaches of the universe, farther than we have ever seen. But this patch was in space-terms just a spot,
like if you pointed your finger to the sky and made a dot. Thousands of galaxies were in that one spot,
and inside those galaxies were billions of stars. As for changing numbers of galaxies, in 2016
some scientists said there were more galaxies in the visible universe than first thought,
and it could hold something like 2 trillion of them. Each would contain millions or billions of
stars, and a whole load of planets. Again, this is a very rough estimate. We think we should expand on why billions
turned to trillions, so here goes. As Forbes wrote in 2018, for a long time just
how many galaxies there are in the universe has been a thing of mystery. We thought perhaps there were thousands, then
millions, and then billions. Telescopes kept getting better and the number
kept increasing. As we said before, for quite a while now we
thought there were maybe somewhere from 200 to 400 billion, but then all of a sudden-
bang- we hear two trillion. Astronomers over time had more advanced equipment
and began to see galaxies that couldn’t be seen before. But as things go, some things are so faint
it’s hard to see them, and some galaxies are are caught up in the expansion of the
Universe and they can be undetectable. This poses a problem when you are trying to
count galaxies. Then technology got better again, and scientists
pointed at small places in space and observed what they called a “narrow, pencil-like
beam.” As said before, astronomers could see how
many galaxies there were in that small space and then extrapolate for the rest of the universe. But there is a young and old universe, and
it keeps evolving. They see the effect of dark matter and dark
energy,as well as small, seed fluctuations. These will grow and in time become stars,
more galaxies, and more clusters of galaxies. Because of this constant evolution of the
universe scientists have now upped the ante, saying that it’s possible that there are
two trillion galaxies. As the Forbes article states, “The faintest,
smallest, most distant galaxies of all are continuing to go undiscovered, but we know
they must be there. For the first time, we can scientifically
estimate how many galaxies are out there in the Universe.” The writer says we are just starting to get
a grip on what he calls the cosmic puzzle, and beginning to understand just how the universe
grew up. This is important in regards to today’s
show. Of course it’s not an exact science because
as we said some galaxies are invisible or faint, so scientists infer how many there
could be. Otherwise they would tell us there are like
two trillion and 58 galaxies. And here you are sat on your bed on planet
Earth thinking you are the center of the universe! If you are now feeling insignificant don’t
worry, the fact you are thinking about it is pretty special in itself. Now let’s get to the real topic of today’s
video. We’ve digressed somewhat, but we feel that
now that you have a picture of the universe in your head the topic will make more sense. As you now know, there are lots of galaxies
not visible to astronomers but all the time they are on the look out for more. And as we write this they have done just that,
galaxies some astronomers have called “primordial beasts.” If you don’t know what primordial means,
it’s related to things that exist from the beginning of time. Researchers at the Institute of Astronomy
at the University of Tokyo said the Hubble Telescope just couldn’t see some galaxies
due to their long wavelengths being invisible to any eye and undetectable by a telescope. So, they turned to something called the Atacama
Large Millimeter/submillimeter Array, aka, ALMA. It’s shared by a bunch of countries and
it wasn’t a cheap telescope, coming it at $1.4 billion. An expensive piece of equipment if ever there
was one. But ALMA, according to these researchers,
is worth every cent because it’s just found these new galaxies. Those astronomers say they have just discovered
a huge bunch of massive galaxies that were formed close to the beginning of the universe. As you know, there was a big bang, and that
was something like 13.7 billion years ago. The universe was extremely hot and dense,
and then things cooled down and the conditions were right for matter to build. Those scientists believe the new galaxies
were around in the beginning. They have been called a “missing link”
in the evolution of galaxies, said to be the ancestors of the modern-day massive galaxies. For a long time astronomers have been working
on something called the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, aka, CANDELS. They observe galaxies in order to try and
figure out galactic evolution. We can call this the cosmic dawn, when galaxies
formed, and the cosmic noon, a period of vigorous star formation in those galaxies. So those astronomers looked closely at 63
infrared-bright galaxies in what’s called the CANDELS field. Something called the Spitzer Space Telescope
could detect infrared radiation in those fields, but it would just disappear when looked at
through near-visible wavebands. This might all sound confusing, so let’s
just say ALMA did detect these galaxies. What were once invisible galaxies became visible. These galaxies are said to be bursting with
new stars, but they are covered by dust and hard to see. So these new galaxies it’s thought came
about around one to three billion years after the big bang. Stars were formed, but stars also died. When they die, they create dust. Supernova explosions are messy affairs, a
galactic version of a full vacuum-cleaner bag bursting. The thing is, according to one American expert
in galaxy evolution, astronomers are unsure why there was so much dust so soon in the
formation of those galaxies. It was too early for so much dust. That expert said this about the mess, “This
means we do not understand star formation in the early universe. Theory is, as of this paper, based on outdated
observations.” The leading researcher in Tokyo said this
could teach us a lot about the formation of the universe. He told the media, “This is the first time
that such a large population of massive galaxies was confirmed during the first two billion
years of the 13.7-billion-year life of the universe.” These galaxies that were invisible could be
that missing link. He said these new galaxies might help us to
learn more about this stuff called invisible dark matter, which is important when we are
thinking about the structure and formation of galaxies. We might come to know galaxies’ precise
ages and what part they played in the evolution of the universe. In Earthly terms it’s like finding something
in the fossil record that gives us more insight regarding the beginning of life on this planet. As another U.S. astronomer put it, “This
is a surprise the universe had for us.” What do you think about all of this? Are you excited as those star-gazing scientists
are or don’t really care? Tell us in the comments. Also, be sure to check out our other video
What Are Some Mysterious Objects in Space We Can’t Explain Yet? Thanks for watching, and as always, don’t
forget to like, share and subscribe. See you next time.

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