Posts Tagged ‘astronomy’
Who Discovered Space?
This was a question posted on Yahoo Answers today, in the Astronomy & Space category. I strongly suspect it was posted as a joke, considering what I know of typical behaviour in Yahoo Answers. The replies to it pretty much bore that out, every reply was some variation of “the first human that gazed up into the sky.” I thought this was fascinating on several levels. Fascinating because all of the people who answered that were full of shit, even though they thought they were making sense. And secondly, because it is an interesting question, do we know who the first person was who realized that the night sky was something akin to what modern science knows it to be?
First, why were the people who thought cavemen discovered space full of it? Simple, cavemen didn’t have our modern knowledge of the Universe, so when they looked up at the night sky, they didn’t have the faintest idea what they were looking at. And they certainly didn’t imagine that the points of light they were seeing were planets or other versions of the Sun, why would they? When learned men started trying to understand what they were looking at, they came up with celestial spheres. These were spheres encircling the Earth with lights embedded in them. They did notice that the planets in the sky moved against the background of other stars, so they decided there were spheres nested inside spheres.
Yet so many people who answered the question assumed that cavemen looked up and comprehended the vast void of space that we now know we are looking at. To me this is a wonderful example of one of human’s greatest weaknesses, people simply assume that other people see the world through their eyes. Most people make this assumption on such an implicit level that they don’t even realize they are doing it. I would actually be curious to know what the people who answered would say if they knew I thought they were full of shit. I would hope that some would agree, and realize they hadn’t thought it through or knew they were giving a flippant answer. Some though would no doubt defend their answer, by one tiresome means or another. What is it with people who can’t admit they are wrong?
Moving right along, who did “discover space?” Copernicus would be one possible answer, he is in fact the fellow that realized that the Sun was at the centre, not the Earth. That’s as far as he got though, Copernicus still thought that the heavens were transparent spheres with lights embedded in them. It may sound silly in to us, but one has to remember than these were people who sincerely believed that there was a creator, a creator who had set this all up for our benefit. So the scientists of the day weren’t so much as looking for naturalistic explanations, they were just trying to understand God’s creation. Tycho Brahe is another one who realized there was a problem with the celestial spheres, he observed that comets apparently passed through them on their journeys to and from the Sun. Still, that’s as far as he got.
No, the real answer is an obscure astronomer named Thomas Digges (1546 – 24 August 1595). He was the first to realize that there were no spheres at all, or at least there was no outermost sphere, that the points in the sky we were seeing were spread throughout a near infinite void. And I mean near infinite, he also realized that what we were seeing in the sky was proof that the Universe was not infinite. How the hell did he come up what that? He reasoned that if the universe was infinite, that any direction we looked there would eventually be a star, and the night sky would be as bright as the daytime sky. It’s called the dark night sky paradox, one of humanity’s first stabs at defining the scope of the cosmos.
In other words, until 1600 or so, people gazing at the night sky might have been amazed at what they were seeing, but they had no clue what they were looking at. They assumed that whatever it was, it was just set and setting for the Earth, a God given backdrop to the play that was humanity. Thomas Digges was apparently the first to grasp that what we were seeing in the night sky was far grander than humans had ever imagined. So the next time the gentle reader is staring up at the night sky and wondering at the vastness of it all, it was Thomas Digges who led the way more than 400 years ago.
An eye blink in human history. Have a great weekend everyone.
(Welcome new and old readers. I hope you enjoyed this post. As of January 2018 I have resumed regular blogging on my new Patreon version of Doug’s Darkworld. Science, history, current events, and posts about a certain president who can hardly go a day without inspiring a blog post.)
(The above image is public domain under US copyright law. It’s actually the work of the esteemed Mr Digges, not only the first translation of Copernicus into English, but the first illustration of the stars as scattered in a void. We don’t apparently have an image of him, but his life’s work lives on. I drink to his vision and his memory, skol Mr Digges!)
Stephan’s Quintet
This is Stephan’s Quintet, a group of five galaxies. It was discovered in 1877 by French astronomer Édouard Stephan. Now a grouping of five galaxies in the sky is obviously pretty cool, but it’s cooler than that. Four of the five galaxies, the ones with the yellowish tint, are not just visually grouped together, they are actually grouped together. These four galaxies are the first compact galaxy group discovered, and they are the most studied compact galaxy group.
This is of course what Stephan’s Quintet looked like 300 odd million years ago. The Earth was a different place then, but it would still have been strangely familiar if one was magically transferred there. The land was covered with trees and vegetation. Lots of ferns and seeding plants, but no grass or flowers. Bugs, insects even. Small lizard-like things, and lots of amphibians. I suppose I should say it would look familiar at a distance, up close the bugs and plants and lizard-like things would be odd. The only thing really familiar looking would be the ferns. And the sharks. Sharks have been with us a long time, when nature hits on a good idea, she sticks with it.
However, I digress. So what is meant by a compact galaxy group, and what is its significance? This is a group of galaxies that is so gravitationally bound with each other that they are basically in the process of combining. These galaxies have had a number of close encounters and partial collisions already. It may not look like much in the picture, but the various loops and swirls of stars resulting from these collisions give astronomers great insight into the structure of galaxies. And what science doesn’t know about the structure of galaxies dwarfs what they do know, so research will continue.
As for unscientific observations, imagine what the night sky must look like from a planet in the midst of these collisions. It would be like the Milky Way on steroids, there would be planets where the night sky was nothing but huge galaxies from horizon to horizon. It would be spectacular, and make our starry skies look drab in comparison. And especially considering some of these stars (and attendant planets) will have been flung into intergalactic space as a result of these collisions. People don’t realize that our view of the heavens is terribly obscured by dust seeing as we are deep inside a galaxy. On the other hand, intelligent species on such planets would eventually be dismayed when they realized that travel to other star systems was going to be next to impossible. They would have a great view, but very likely be isolated forever.
Humans at least have a shot at exploring nearby star systems. And that’s a topic for an upcoming post.
(The above image being a NASA image is being used legally. NASA does not endorse Doug’s Darkworld, and my use of their image in no way is meant to suggest that. Credit and copyright: Hubble Legacy Archive, ESA, NASA; Processing: Al Kelly I don’t think I need to explain why I chose an image of Stephan’s Quintet to illustrate a post about … Stephan’s Quintet. Oh, and even in dense clusters, stars are still very very far apart, so these galactic collisions will involve the actual collisions of very few stars.)
What the Hell is That? (Number 3 in a series, if you want to guess, don’t read below the image.)
OK, we’ve all seen this before, on the view screen of the Starship Enterprise:
Kirk: “What is it Mr Spock?”
Spock: “I don’t know Captain, it’s not showing up on our sensors. It appears to be some sort of void in space.”
Kirk: “It’s avoiding us?! Arm phasers, load photon torpedoes!”
Spock: “It doesn’t appear to be hostile Captain, is that necessary?”
Kirk: “You heard me Mr. Spock. Fire!”
Dr McCoy: “Jim, did you take your medications this morning?”
Kirk: “Fire! Fire! Fire!”
Ah, I loved that show. We all did, what wonderful memories. Alas, that particular episode didn’t end very well as I recall. Moving right along, so, is that a void in space? Well, at one time that’s exactly what astronomers thought, they thought it was just what it appears to be, a region of space where for whatever reason there are no stars. Not for long though, astronomers quickly realized that these voids were clouds of gas and dust obscuring the view of background stars and galaxies. (There are actually a few small areas like this that are indeed voids in space, but that’s fodder for another post.) And in their usual exciting lexicographic way, astronomers dubbed these “molecular clouds” or “dark globules.”
OK, so what are we looking at here? A cloud of gas called Barnard 68. It’s about 500 light years away and about half a light year across, it could swallow up hundreds of solar systems. Well, gas and dust. Inside the cloud, its about as dark and cold as it gets in this universe. There’s a lot of these puppies in the Milky Way, our galaxy. They are like 1% of the volume of the galaxy, but about half the mass of the gas in the galaxy. They come and go very quickly as galactic times go, in the millions of years. We think of the galaxy as static, but in the long term it’s a wildly swirling mess, and these clouds of gas are a big part of the picture. It’s not even really understood how they form at this point.
Speaking of points, is there one? Of course! These clouds are where stars are born. For as of yet some unknown reason, the gas collapses or condenses into new stars. Our sun and the Earth and the very atoms that make up our beings were once part of a cold dark cloud such as this some billions of years ago. Look at your hand, it was literally once molecules scattered across a cloud as imaged above. And were people in some long dead alien species looking at images of the cloud that formed our solar system and wondering what it would spawn? Barnard 80 is the future, the cloud you are looking at now will, billions of years from now, be stars and planets such as our own.
By then though, Earth will be an airless cinder orbiting a near dead star. Doug’s Darkworld will no longer be updating. Will any hint of humanity remain? I think so … and again fodder for anther blog. I could blog forever, or at least die trying.
(The above image is from APOD, a bigger version of the above image and various details including copyright info can be seen here: Barnard 80. I chose to write about this image because of the basic wonder of it all. And as part of a bigger writing project, I have decided that Genesis needs to be rewritten, the late Bronze Age shepherds who wrote the first version were sincerely trying, but they lacked the tools to see how grand God’s creation really is. Time for Genesis 2.0 )
What the Hell is That? (Number 2 in a series, if you want to guess, don’t read below the image.)
Yeast cells in a petri dish? Higgs Boson particles in the LHC? Nope, this fascinating image is an infrared view of the exact centre of our galaxy. The image is about one light year wide, and the animation loop covers a period of eight years. And it’s not obvious, but the moving stars are actually orbiting around the yellow cross at the centre of the image. In fact our sun is orbiting around that yellow cross, every orbit taking about 200 million years. That means the Sun is 22 1/2 in galactic years, just a young whippersnapper in it’s prime.
Cool new tunas so far, but it gets cooler. Again, it may not be obvious, but those stars are really moving. Look how slowly the other stars in the image are moving compared to the central stars. The only explanation so far is that they are orbiting something really massive at the yellow cross. In fact calculations show that whatever it is, it masses more than five million Suns! Well, astronomers have a pretty good idea what it is, they think it is a black hole, something that appears to reside at the centre of most if not all galaxies like our Milky Way.
Being a black hole, we can’t see it of course. It only reveals itself in x-rays and the motion of stars orbiting it. Is it eventually going to suck up the entire galaxy? No, more than the Sun is going to suck up the entire Solar System. Well, OK, yes, eventually everything in the Universe will get sucked into black holes. Black holes do slowly decay becasue they emit Hawking radiation, and eventually they will all be gone, there will be no more entropy possible, and the Universe will experience heat death, and be nothing but a near infinite incredibly thin cold near vacuum. That won’t be for about 10100 years though, so it’s safe to say that humanity has far more pressing concerns to worry about.
It’s still amazing to me what we know about our Universe now compare to when I was a kid. And I will continue to share images that amaze me. The black hole at the centre of our galaxy is now in the process of gobbling up a huge cloud of gas, if I can find a good picture of this I will post it.
(Image Credit: A. Eckart (U. Koeln) & R. Genzel (MPE-Garching), SHARP I, NTT, La Silla Obs., ESO It’s basically a NASA image and as such may be used pretty much freely for non-commercial purposes. “It is estimated that 3.71 X 10^10 “first-star-tonight” wishes have been wasted on Venus.” OK, a little astronomer humor there. With emphasis on little, I think it’s safe to say that not many stand up comics got their start in astronomy.)
A Space Exploration First and SETI Ramblings
This photograph is another historic first in space exploration. The big orange blob in the centre is a star, prosaically named 1RXS J160929.1-210524. It’s a k7 dwarf star which means it’s a little smaller and cooler than our Sun. It’s about 500 light years from Earth, so we are seeing this star as it was just a few decades after the new world was discovered (well, rediscovered) by Columbus. In any event, here’s the historic part. See that little orange dot at the upper left? That’s a planet orbiting 1RXS J. This is the first photograph ever taken of a planet orbiting another star using visible light from a ground based telescope. This is something that in my youth was thought to be impossible, but science just keeps moving along. It’s not a terribly interesting planet, at least from any practical standpoint. It’s hotter than Jupiter, larger than Jupiter, and orbiting at a vastly greater distance from its sun than our Jupiter does. Its heat comes from the fact that it’s a new planet, maybe only some five million years old. Still, this is one cool photograph in my estimation, but I am a bit of a space exploration nerd.
In other space exploration news I’m still crunching slowly through the book on SETI I’m reading. And while our efforts to find aliens have come up snake eyes with every roll, it’s not quite as bad as it may seem. That’s because our efforts to locate alien civilizations are pretty much exclusively oriented towards looking for beacons. IE we are looking for aliens who have set up giant radio frequency transmission stations to announce to the galaxy that “here we are.” As any astute person can imagine, there’s a lot of assumptions underlaying our search. First we’re assuming aliens would use radio frequencies to attempt to communicate in. Second we’re assuming they would go to a lot of trouble to build such a transmission device, beaming a powerful radio signal in all directions is no mean feat. So why are we looking for what admittedly seems like a long shot? Because it’s all we really have the technology to listen for right now. I am reminded of the story of Nasrudin and the lost key:
Once, a man found Mulla Nasruddin searching for something on the ground outside his house. On being asked, Nasruddin replied that he was looking for his key. The man also joined in the search and in due course asked Mulla: ”Where exactly did you drop it?” Mulla answered: ”In my house.” ”Then why are you looking here?” the man asked. ”The light is better out here,” replied Mulla.
Granted we may eventually find a beacon, but it’s probably not our best option. We could set up a radio receiver to carefully listen for things like military radars and carrier waves and other accidental alien made microwave noise from nearby stars. Alas a receiver that sensitive is a bit out of the SETI budget right now, so we’re stuck with optimistically listening for beacons.
Another tidbit I picked out from the book is that radar searches of the Lagrange points didn’t find any alien probes parked there. (I discussed Lagrange points in an earlier post.) Well, to be more accurate, they didn’t find anything bigger than a metre across. Well, who says an alien probe has to be bigger than a meter across? Aliens with advanced technology might be able to build a perfectly fine probe in a small package so to speak. So I still think more efforts should be made to search various Lagrange points in the Solar System. It’s just such a logical place to park a probe if one wanted to monitor the Solar System. Well, one logical place. It’s also been pointed out that something orbiting in the asteroid belt would be a good place to hide. (And no, the asteroid belt isn’t this seething mass of colliding boulders as is shown on so many incredibly lame sci fi shows and movies, snarl.) The point here is that a huge probe would look like a small asteroid, so for all we know we’ve already spotted alien probes in the solar system. We just haven’t recognized them yet.
Lastly, since this seems to have turned into a pure SETI post, I’ve decided that I’m even more convinced that aliens either don’t exist, are so rare they might as well not exist. My thinking here is that even in our first few decades of space exploration we have left very obvious signs of our presence on two bodies in the Solar System already, not to mention dozens or hundreds of defunct probes and space junk floating around in space. And some of this stuff is going to persist for a long time, the tracks made by the rovers on the Moon will be visible from orbit for hundreds of thousands of years. And the landers and such on the Moon will be around for millions of years. The stuff on Mars won’t last as long, but still, there will be obvious signs we were there for centuries at least. My point here is that in a few short decades we have left a lot of debris around the Solar System. Well, if interstellar travel is at all feasible and there have been aliens visiting the Solar System, they’ve sure been careful not to leave anything behind. High resolution images of the surface of the Moon and Mars have been public for a long time, and lots of people have gone over these images with a fine tooth comb … and found buttkiss. That’s not to say we won’t find something some day, but if we really lived in a Star Trek or Star Wars type galaxy with aliens flitting all over the place in starships, shouldn’t there be more junk laying around?
I mean, one can go to the smallest remote island on Earth, and there will be human made debris washing up on the shore. Granted we haven’t looked on all the “shores” of the Solar system yet, but I’m more convinced all the time now that aliens fall into the same class as Bigfoot or Nessie, it’s getting awfully hard to explain the lack of empirical evidence. So one can safely go see the new Predators movie, knowing full well that the chances of actual hostile aliens showing up to use us for target practice is negligible.
Have a great weekend everyone.
(The above image is claimed as Fair Use under US copyright law. It’s not being used for profit, is central to illustrating the post, and is most definitely a historically important image. Credit: M. van Kerkwijik / R. Jayawardhana / D. Lanfreniere / Aura / Gemini Observatory. Next week, more weird entertaining stuff and lesser known paranormal phenomena. The Bimini Road, Tatzelworms, Ica Stones and all the rest.)
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