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What Happens In Coma?

The Invisible Galaxies

  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 – 200billion 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 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 AndromedaGalaxy, 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. That means if we traveled 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 traveled 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 have200 a 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 HubbleSpace 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 2016some 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 being 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.  This is important in regards to today’s show. Of course, it’s not an exact science because 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 do not worry, the fact you are thinking about it is pretty special in itself.  As you now know, there are lots of galaxies not visible to astronomers but all the time they are on the lookout 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 the 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 63infrared-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 through near-visible wavebands. 

This might all sound confusing, so let's just say ALMA did detect these galaxies. What was 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, galactic version of a full vacuum-cleaner bag bursting. That expert said this about the mess, “This means we do not understand star formation in the early universe. The 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.”“This is a surprise the universe had for us.” What do you think about all of this? 

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