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The Best Views of the Universe are from our Backyards
Jun 25 2009 06:19 AM | Tom Benjamin in Astronomical History
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Science fiction and time exposure telescopic pictures have long provided mass audiences with tantalising but completely false views of the universe. When you mention having seen a particular globular cluster or galaxy to someone they are apt to murmer “oh it must be beautiful”. In fact, often it is anything but so. That little smudge or pair of dots in the eyepiece might be more akin to glimpsing a president, pope or popstar from a great distance – “I saw the Beatles live”.
For example, our companion galaxy, M33 is notoriously difficult to see. Although it is a face-on member of the Local Group close enough to span a chunk of sky easily large enough for the naked eye it is extremely faint and challenge enough for binoculars. Even with large binoculars it is only a hazy patch. If there are observers in m33 looking at our Milky Way we would look much the same to them.
Yet how many of the billions of people on Earth know of the existence of this near neighbour, let alone how many have ever glimpsed it? One could argue that this ought to be a part of basic geography education –ie- where we are in the universe. Alas, astronomy is often seen to be part of a science curriculum suitable for advanced students.
The non-science crowd is left to learn about their place in the universe through motion picture animations and press releases of time-exposed and enhanced space mission photos. The voyages through space depicted in science fiction or science documentaries emphasise the grand size of the universe – implying we are but a speck and that our views are limited.
In fact, quite the opposite is true. We live inside a galactic arm. That means we are privileged to see out from and into a fairly representative galaxy. Isn’t that the universe? All we can see of the universe today is galaxies and their components. By definition, we can’t see dark matter. So we have a ringside seat.
As for the rotating galaxies of science fiction this is pure drama. Even a dinosaur still alive today would not have seen much rotation in the past 60 million years. Things in space cover vast distances so seem immobile from our perspective – but the same would apply to observers anywhere else. Climbing aboard a rocket ship does not change our galactic perspective in the way that an airplane does to Earth. Stars do not rush by. Even the asteroid belt might not be dense enough to offer much visual stimulation. A mission to Mars would just be months of seeing the same sight out the window – black.
But through a modest backyard telescope we can see movement. Satellites are abundant. If the observer tracks one using low power the sight is very much a real picture of space – a bright dot moving quickly across a backdrop of stars on jet black. That is what things look like in space.
What about going into space for a look? Astronauts get a great glimpse of Earth but their view of the stars is through portholes and space suit visors. Their view flying over the moon is clearer than we get through a backyard telescope but then how comfortable is a space capsule? From the surface of the moon things should improve but we still have the problem of the space suit. Night time there is cold enough to make Antarctica seem tropical.
As for galaxies, they are not inherently beautiful to our eyes. They are essentially a vacuum. Only because each of the points of light within is a nuclear furnace do they produce a feeble overall glow we can see. But they are far from bright. When the Milky Way is overhead (in our Southern Hemisphere) the merest candle, streetlight or full moon blocks most of it out, let alone the Sun. People living on a planet with more than one moon might never see their own galaxy until their civilisation was advanced enough to leave their atmosphere and block the moonglow.
Another clear proof of this is the Clouds of Magellan. These companion galaxies have a wide span and a lot of interesting elements visible with binoculars. Their Tarantula Nebula can be glimpsed with the naked eye. But – beautiful? Any Earth clouds in the sky tend to be brighter and can make them hard to see (hence their “cloud” names). If a student ever asked you ‘what would a galaxy look like from outside?’ there is their answer – like clouds. The centre of the Milky Way is called the Star Clouds of Sagittarius. Beautiful? They loom straight overhead in the Southern Hemisphere but the Milky Way covers more of the sky than the eye and brain can take in. Sometimes focussing on the dark patches helps in trying to take in the overall shape and all that it means. It should be no surprise that the notion of a galaxy is fairly recent history. We can only see the shape if we’ve been told what to look for. Even then it has less contrast than the photos.
So where would we find the best views in the Universe? Let’s look back to where we started. Backyard skies used to be dark. Even by the time of Classical Greece cities were not lit. Nobles employed people to guide them home by torchlight. Greenwich and other observatories were able to operate in what have since become urban centres. William Herschel knew that he had great views of outer space. Today city dwellers have to take a car to escape city light (train and bus only take us to lit depots).
But out of town on a moonless night we have the potential for very representative views of the Universe. From the Northern Hemisphere we can see other galaxies. From the Southern Hemisphere we can see our own. Denizens of other solar systems might have better close ups of particular neighbouring galaxies and nebulae or globular clusters in their vicinities but these too will be faint. Too many such objects and they mush together visually and drown each other out. Besides, we can see many such objects from our own backyards with a telescope.
The limitation then is less our locale than our eyes. Cheap large telescopes and binoculars and super wide field eyepieces do a better job of helping us take in the views. But our eye pupils only open so far at night. Extra aperture is lost if we don’t match lens to eye to object.
The best views, then, come from taking different perspectives. Just as our binocular vision gives us depth perception, looking through different devices gives us close-ups, wide angles, satellite fly-bys, Earth rotation movement, multiple-star splits, and dark nebulae focus. It takes a combination of these views to put together a picture of the Universe. This should be no surprise. To take in and comprehend ‘France’ we could view it from the air,.through its radio and TV, from its restaurants and wineries, its countryside, its beaches, its libraries and museums - yet spend a lifetime still learning more. Why would we expect the Universe to be a quick glimpse from a rocket ship?
So backyard astronomers, never let aperture fever or preaching about our supposed ‘insignificance’ tempt you to think you’re seeing any less of what the Universe has to offer. You have as good a view as any.
For example, our companion galaxy, M33 is notoriously difficult to see. Although it is a face-on member of the Local Group close enough to span a chunk of sky easily large enough for the naked eye it is extremely faint and challenge enough for binoculars. Even with large binoculars it is only a hazy patch. If there are observers in m33 looking at our Milky Way we would look much the same to them.
Yet how many of the billions of people on Earth know of the existence of this near neighbour, let alone how many have ever glimpsed it? One could argue that this ought to be a part of basic geography education –ie- where we are in the universe. Alas, astronomy is often seen to be part of a science curriculum suitable for advanced students.
The non-science crowd is left to learn about their place in the universe through motion picture animations and press releases of time-exposed and enhanced space mission photos. The voyages through space depicted in science fiction or science documentaries emphasise the grand size of the universe – implying we are but a speck and that our views are limited.
In fact, quite the opposite is true. We live inside a galactic arm. That means we are privileged to see out from and into a fairly representative galaxy. Isn’t that the universe? All we can see of the universe today is galaxies and their components. By definition, we can’t see dark matter. So we have a ringside seat.
As for the rotating galaxies of science fiction this is pure drama. Even a dinosaur still alive today would not have seen much rotation in the past 60 million years. Things in space cover vast distances so seem immobile from our perspective – but the same would apply to observers anywhere else. Climbing aboard a rocket ship does not change our galactic perspective in the way that an airplane does to Earth. Stars do not rush by. Even the asteroid belt might not be dense enough to offer much visual stimulation. A mission to Mars would just be months of seeing the same sight out the window – black.
But through a modest backyard telescope we can see movement. Satellites are abundant. If the observer tracks one using low power the sight is very much a real picture of space – a bright dot moving quickly across a backdrop of stars on jet black. That is what things look like in space.
What about going into space for a look? Astronauts get a great glimpse of Earth but their view of the stars is through portholes and space suit visors. Their view flying over the moon is clearer than we get through a backyard telescope but then how comfortable is a space capsule? From the surface of the moon things should improve but we still have the problem of the space suit. Night time there is cold enough to make Antarctica seem tropical.
As for galaxies, they are not inherently beautiful to our eyes. They are essentially a vacuum. Only because each of the points of light within is a nuclear furnace do they produce a feeble overall glow we can see. But they are far from bright. When the Milky Way is overhead (in our Southern Hemisphere) the merest candle, streetlight or full moon blocks most of it out, let alone the Sun. People living on a planet with more than one moon might never see their own galaxy until their civilisation was advanced enough to leave their atmosphere and block the moonglow.
Another clear proof of this is the Clouds of Magellan. These companion galaxies have a wide span and a lot of interesting elements visible with binoculars. Their Tarantula Nebula can be glimpsed with the naked eye. But – beautiful? Any Earth clouds in the sky tend to be brighter and can make them hard to see (hence their “cloud” names). If a student ever asked you ‘what would a galaxy look like from outside?’ there is their answer – like clouds. The centre of the Milky Way is called the Star Clouds of Sagittarius. Beautiful? They loom straight overhead in the Southern Hemisphere but the Milky Way covers more of the sky than the eye and brain can take in. Sometimes focussing on the dark patches helps in trying to take in the overall shape and all that it means. It should be no surprise that the notion of a galaxy is fairly recent history. We can only see the shape if we’ve been told what to look for. Even then it has less contrast than the photos.
So where would we find the best views in the Universe? Let’s look back to where we started. Backyard skies used to be dark. Even by the time of Classical Greece cities were not lit. Nobles employed people to guide them home by torchlight. Greenwich and other observatories were able to operate in what have since become urban centres. William Herschel knew that he had great views of outer space. Today city dwellers have to take a car to escape city light (train and bus only take us to lit depots).
But out of town on a moonless night we have the potential for very representative views of the Universe. From the Northern Hemisphere we can see other galaxies. From the Southern Hemisphere we can see our own. Denizens of other solar systems might have better close ups of particular neighbouring galaxies and nebulae or globular clusters in their vicinities but these too will be faint. Too many such objects and they mush together visually and drown each other out. Besides, we can see many such objects from our own backyards with a telescope.
The limitation then is less our locale than our eyes. Cheap large telescopes and binoculars and super wide field eyepieces do a better job of helping us take in the views. But our eye pupils only open so far at night. Extra aperture is lost if we don’t match lens to eye to object.
The best views, then, come from taking different perspectives. Just as our binocular vision gives us depth perception, looking through different devices gives us close-ups, wide angles, satellite fly-bys, Earth rotation movement, multiple-star splits, and dark nebulae focus. It takes a combination of these views to put together a picture of the Universe. This should be no surprise. To take in and comprehend ‘France’ we could view it from the air,.through its radio and TV, from its restaurants and wineries, its countryside, its beaches, its libraries and museums - yet spend a lifetime still learning more. Why would we expect the Universe to be a quick glimpse from a rocket ship?
So backyard astronomers, never let aperture fever or preaching about our supposed ‘insignificance’ tempt you to think you’re seeing any less of what the Universe has to offer. You have as good a view as any.
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