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Bringing the Universe to Your Classroom!


Saturday, April 7, 2018

Look - Up in the Sky: It's a Bird! It's a Plane!

... Well, yes, it probably is.

As an astronomer, with an interest in astro-biology and, therefore, in the possibility that life exists elsewhere in our universe - invariably, almost daily - someone will ask me something like: "Do you believe in aliens and UFOs?" My answer is, generally, something like: "I *ABSOLUTELY* believe that, "they", are out there. They're just not, here."  But they don't like that answer, and at that point, the conversation usually turns to questioning the current state of my sanity: "How can you possibly believe in life in the universe - but NOT in UFOs?" Well, there are some really good reasons for this; and, here is my answer:

"Tweet" "Tweet" "Tweet"!

THE SHORT STORY:

1) Universal Constants There is no 'getting around' such things as universal constants: they are constants because they are, by nature, unchangeable; nothing can alter them. They obey inherent, long-proven, immutable laws of physics that are the same - everywhere in the universe. (How we know this, is another, very long story - so forget it.)  But, what this means, is that, no, intelligent, alien life-forms (or, 'Extraterrestrial Biological Entities', if you prefer), could build a vessel for space travel that could 'out-maneuver', or, 'get around', say, the speed of light, for one. They would be subject to the same distances and travel times that we would be subject to. Even if they were from some planet in the nearest star/planetary system, which is the Proxima Centauri system - and even if they could travel at the speed of light - it would take their spacecraft 4.2 years to arrive here at Earth - the same length of time that it takes light to travel that very same distance. 

So, let us take a look at light for just a minute: 'Light', is a mass-less, neutrally-charged radiation from a particle called a photon. Photons are propagated through the vacuum of space in waves, at a constant speed, or, velocity. That velocity never varies, and we can use it to measure the distance to any celestial object by calculating the time it takes to travel from one place to another. The way we can measure these distances is by knowing the speed of light itself, which has been determined, and confirmed, countless times, to be exactly: 186,282.3976 mi/sec. Therefore: light from the moon takes 1.3 seconds to arrive at our eyes, here on Earth. Light from the sun takes 8.5 minutes. From the nearest star, Proxima Centauri, to our Solar System, the travel time for light is 4.2 years.  From those travel times we can define the distance that light travels, in, say, one year's time - 5,874,601,670,000 miles. This is where we get the term light-year (LY) from. So, one light-year (LY) = 5,874,601,670,000 miles. The term is used as a measure of distance, rather than of time, for obvious reasons. And, as if that weren't bad enough - the next closest star hosting a known planetary system, is Fomalhaut. Fomalhaut ('foam*a*low'), is 25 LY's away. This means that our brave little aliens - in their very special (and, very impossible) light-speed-traveling spacecraft - would take 25 years to get here! After Fomalhaut, comes Pollux, at a distance of 34 LY's, and then, Algieba, at 126 LY's, way out there in interstellar space. There are many, many more stars beyond 126 light-years, this is true, but: nothing in the universe can travel at the speed of light, except light; that speed limit is reserved - for EMS radiations, only.**

The reasons for this are far too involved to get into in this limited space, so, as I had implied, earlier - I won't. You'll have to take my word for it. Violation of these restrictions (where the violation would exist, hypothetically, only), would bring on all kinds of impossible, even, laughable consequences; for example: infinite length-contraction and infinite mass, to name just two. Length-contraction, and mass increase, are two, verified relativistic effects from General Relativity. They are very real - and, they are problematic to mess with - so we're staying away from them. In short, anyone else out there is limited to the same physical restrictions, as ourselves.

The top speed that any of our manned-spacecraft has ever achieved, is about 26,000 mph - that's, one hour, to travel 26,000 miles. That's pretty darned fast, right? Nevertheless, in one hour light will travel 670,000,000 (670 million) miles. So, let's cut our 'little alien friends' some slack, and say that they have built a spacecraft that can travel 100 times the speed of our own. That will give them, a top speed of - 2,600,000 mph! Now, I've calculated it all out, so, I'll skip all the math here, but it's going to take those guys - 11,151 years to get to Earth - from the very closest star!  And if they're from Fomalhaut, it'll take them - only, 44,604 years - to get here!  And if they intended on going back home - they'll need an additional 44,604 years for the return trip! (Are you seeing the collective problem here?) Not a good position to be in, for interstellar space-farers, to say he least.

Next item up for attack:

2) The unreliability of 'eyewitness' UFO reports Most people don't spend much time, on any given night, staring up at the sky. They might notice the moon and stars, an occasional meteor, or, falling star - but that's about it. But, astronomers, typically, spend many hours on any, given, clear night peering intently into the sky. Not only are they in, direct, visual contact - night after night, year after year - but, they also have highly sensitive instruments, trained on various sectors of the celestial sphere.

I have never known any astronomer to file a UFO report - or, even, having had a sighting. Why should this be, when, so many others have?! The answer is not that astronomers are involved in some kind of UFO/conspiracy cover-up (if they were - I would have spilled the beans a long time ago). No; there is no need to be. You can't conspire about something that, you understand, does not exist. Moreover, unlike so many others, when it comes to strange-looking objects in the night sky, the astronomer has seen it all. She/He understands the many kinds of objects that the night sky has to offer, which, the typical layperson, couldn't identify if their lives' depended on it.  I really don't mean to sound so harsh, but, that's a harsh truth - and I've heard all kinds of stories, misrepresentations, and misinterpretations. The  problem that we astronomers have with this, is, that so many people think they can.

There are many, many celestial phenomena that the average layperson has never or, possibly, will never experience, such as, bolide or fireball meteors - especially the rare, larger asteroid fragments. Back in April of 1966, a large, iron asteroid fragment, had entered the atmosphere, at a shallow enough angle that its long flight through the thickened air slowed it considerably. Anyone not familiar with such sight could easily have mistaken it for a burning aircraft. The 15ft.-diameter chunk of space-iron, which, emitted, glowing green and yellow at its leading edge, or, 'head', took about 45 seconds to cross the sky, from horizon to horizon, moving parallel to the thickened column of air hugging the Earth's surface at such a low angle. The object left a trail of glowing, orange fragments, along its path - coupled with a wide corridor of white smoke, which I could trace all the way back to its point of origin (exclusive to my position). Measurements taken from Harvard College Observatory of the flight-path of the object, determined that it was 160 miles, due West, of my position on Cape Cod, and 60 miles in altitude, when it entered the atmosphere moving northwards, over New Jersey.  Then the rough, melting, mass of rock and iron, 'skipped' back out of the atmosphere, somewhere over Ontario, Canada. Sightings of asteroid passages of this magnitude are very rare; typically, a once-in-a-lifetime event. I was very fortunate to have seen two of them, as well as, the following, aging Earth satellite. 

In late July of 1979, I was spending the afternoon at Quissett Harbor, when I was treated to a replay of the 1966 asteroid flight. Low over the treeline, at the northwest horizon, there appeared a brilliant, blue-white object about the size of the full moon moving towards the southwest at an elevation of about 40 degrees. The object produced a long, white train of smoke behind it, which I was able to trace back to its point of origin. The object moved slowly across the sky at about the same velocity as that of the '66 fireball. I later learned that it was a large' chunk' of the Skylab, orbiting space station, which had suffered orbital decay that afternoon and plummeted through the atmosphere, at a moderately low angle, and ended up - in pieces - in the Australian Outback.  And there's more confusion in the sky: planetary groupings, conjunctions, opposition's, some of which, even include the moon; comets, asteroids, satellite panel, and, antennae flares, the International Space Station, and, even, 'stationary meteors' (I've witnessed exactly one case of the latter). 

My point, is, that these, admittedly, spectacular events are very, very rare and could confuse anybody that didn't have a background in astronomy, and meteorology - and that includes pilots.  Aircraft pilots have it particularly tough when it comes to identifying objects in the sky that they aren't familiar with. One of the reasons for this is lack of depth-of-field, or, an inability to determine an unfamiliar object's size, distance, and proximity, for want of a familiar reference point, or, a familiar object to compare with. This is because 'binocular vision', or, the 3-D, or, 'stereo' aspect of an object, beyond about 50 feet, is lost. This is the distance at which camera lenses become, 'fixed', at infinity. The 3-D effect is lost at that point and the brain's ability to judge an object's relative distance, relative velocity, or, even its dimensions, is lost, unless the object is one that the viewer can recognize, and therefore, it's dimensions recalled to memory. Even then, relative distance and relative velocity are judged - not by vision, per se - but by the observer's familiarity with the object. 

Aside from those celestial and meteorological surprises, and at least as important, is the subject of visual phenomena. For example, small, star-like points of light when seen in the sky, against a dark background, can produce, physical, visual phenomena like the one that I experienced, one night, in younger days, while watching the stars at the beach with my brother... Standing, facing the southern horizon and opposite our positions on the beach, we noticed a 'star' that was moving very slowly along the horizon and toward our right. After several minutes, it became apparent that the 'star' had a second component to its motion; it was moving toward us as well. After about another minute, it grew much brighter, and larger, and then -- began to sway, slightly -- back and forth, like a pendulum! We both saw this. At the same time. And at that point, I said to my brother, "Are you seeing what I am?!"  He answered, "You mean, it's wobbling!?"  Yes, that's what we saw all right. Meanwhile, there was no sound, whatsoever. Knowing that this was an impossible feat, for any conventional aircraft, and, that it broke, probably several of Newton's Laws of Motion, I then, yelled to my brother - of all things - "let's ditch into the dune grass - fast!"  Immediately after those, "out-to-lunch" words of wisdom, left my big mouth - we both heard the tell-tale, unmistakable - "thwup, thwup, thwup, thwup, thwup, thwap, thwap, thwap, thwap" - of approaching, doppler-compressed helicopter rotor blades....and then, we went home. And we didn't mention it, to anyone - ever again.

This common, but typically unrecognized, visual 'mirage' is called the 'pendulum effect'. It's just one of many possible anomalies of the human, eye-brain interface. There are others (some, you wouldn't believe!), like a  type of image 'flicker' that can cause a seizure in certain, affected persons. And there are others, even some that you have, likely, unwittingly experienced, at one time or another. For more enlightenment, see: http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.1977.sp011686/full

On any given day, there are around 200 reports of UFO's, around the globe. And there are also  those who have a tendency toward 'conspiracy theory' out there, as well. Current television, 'documentary'-style programming which focuses on ancient alien visitation, and the like, are presented in serial form. They are able to continue on, and on, and on - only because they have nothing of import to present. Speculation is, seemingly, blissfully infinite. An important point once made by the late, Carl Sagan, very simply, states: "Extraordinary claims require extraordinary evidence"; and that - is the missing component in the data from those who make such claims as, possessing 'proof', of flying, extraterrestrially-piloted, vehicles/crafts, etc., over the skies of Earth. The 'proof' - in any form - of visitation by beings from other worlds, simply, doesn't exist. And, not to burst anyone's bubble - but, here's a little quote of my own: "In Science, you go with what you've got - not, with what you'd like to have".

So, I feel that I'm safe in saying, that, our skies are not full of the alien spacecraft, and their pilots, that most witnesses of 'UFO's' believe there to be. If and when that situation ever changes - and it is, hypothetically, entirely possible - it'll be a different story. But for the moment, the reigning consensus on whether or not we're being visited by beings from other worlds, by those who know best (the Astronomers), is, a big, fat "No".  **(This applies to all forms of radiation in the Electromagnetic Spectrum, including: radio waves, microwaves, infrared light, visible light, ultraviolet light, x-ray, and gamma ray radiations; all, are forms of light.)
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Friday, March 23, 2018

How Newton’s Telescope Changed the World

Sir Isaac Newton didn't use his telescope to find any new things in the universe but he did use it to radically transform how we view the world we live in and the universe as a whole.

Sir Isaac Newton is often considered as the greatest Astronomer and Mathematician to ever live. There is a lot of validity to this claim. This article looks at his famous reflector telescope and describes some of his discoveries.

A reflector telescope is one that uses a mirror rather than lenses to bend light and magnify images. Reflector telescopes, because they are easier to make and can be made in sizes much larger than refractors, are an invention that changed astronomy and our understanding of the universe. The largest refractor telescope in the world is forty inches in diameter and reflector telescopes dwarf this in comparison. There are currently several reflector type scopes that are over four hundred inches in diameter.

Sir Isaac Newton surrounded by symbols of some of his greatest findings. Illustration by Jean-Leon Huens, National Geographic Stock
Sir Isaac Newton surrounded by symbols of some of his greatest findings. 
Illustration by Jean-Leon Huens, National Geographic Stock

Why a reflector is better than a refractor

If you are familiar with a prism or a rainbow you can understand why reflectors are superior to refractors. When light passes through glass the different bands (or colors) pass through at different angles and this causes aberrations or problems in the images. This is called chromatic aberration and it gives us distorted views of what we see through a lens. In the time of Newton glass making and lens making was very primitive and the problems of chromatic aberration were not yet overcome. Today we can make lenses that have almost no chromatic aberration but we can’t make them very large. When a lens gets to be really large it gets very heavy and its own weight will distort the lens and ruin the image.

Newton’s telescope solved these problems. A mirror doesn’t pass light through it. It simply bounces all the light off the surface. There is no chromatic aberration at all. And because you only need to bounce light off the surface you can place the whole mirror on a supporting structure or base which takes a lot of the weight off the mirror. This way you can build much larger mirrors without any distortion.

It is commonly thought that Newton invented the first reflector telescope but it isn’t true. Credit for making the first reflector goes to and Italian Monk, Physicist, and Astronomer named Niccolo Zucchi. He published a book on Optics in the 1650’s and it is this book that inspired Sir Isaac Newton to build his own telescope. Zucchi created his first reflector around 1616 while Newton completed his first (and famous) telescope in 1670. But while Zucchi did make some new discoveries with his telescope it didn’t work well and was difficult to make and to use. It was Newton’s telescope that worked really well and that brought the art and science of reflectors into the world of science.

The real genius of Newton’s Telescope

All of that stuff is remarkable but there is something much more important in Newton’s Astronomy and in his telescope. He didn’t after all, discover moons around Jupiter like Galileo did, or plot the return of a comet like Halley did. But what he did do was tie in Mathematics, Astronomy, and our understanding of the universe using his telescope and his theory of universal gravitation. He proved mathematically that gravitation was a two way operation and that while the earth pulled on a falling apple so the apple too pulled on the earth. This was clearly seen, calculated Psychology Articles, and confirmed in the motions of heavenly bodies which was refined and made possible by the new science of reflector telescopes which we can credit to Newton.

Sir Isaac and his telescope carried on with the work of Copernicus and Galileo by furthering our understanding of the universe we live in and helping us to realize there are laws that govern the whole of the universe. And this rule holds true for falling apples and for planets revolving around stars.

Sir Isaac Newton's Original Reflector Telescope. Image by The Royal Society of London.
Sir Isaac Newton's Original Reflector Telescope. Image by The Royal Society of London.

The actual telescope that Newton built still survives today and is in the care of the Royal Society of London. They keep it on display in London and sometimes it travels the world as part of an exhibit.

Will Kaliff

Source: Free Articles from ArticlesFactory.com
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Thursday, March 22, 2018

Explore the Night Sky without a Telescope

You don’t need a telescope to see a lot of wonderful things in the night sky. For example five of the planets are often readily visible with the naked eye. There are lots of amazing things you can see and this guide will help you find them.

To maximize what you can see in the night sky there are a few things you should do as preparation. Of course the first thing you need is a clear and cloudless night. And this includes the moon. You should try to do your observing on a night with no moon; or at the least the smallest sliver of moon possible. Its brightness will wash out many of the dimmest and most dramatic objects in the sky. Second you should consider your comfort. Make sure you dress appropriately for the weather and bring extra layers of clothing if you are observing during cold months. The temperature late in the evening can be substantially lower than it is during the day and because observing the sky means not moving around much you will be even colder. Bring along any items to help your comfort like a lawn chair or a reclining lawn chair so you can look up without craning your neck.

Stargazing and Meteor Shower Observing - Image by NASA
Stargazing and Meteor Shower Observing - Image by NASA

Find yourself a spot to observe from that is as dark as possible. This means get away from street lights, city lights, house lights, or any other type of light source. Ideally you should drive away from any city that is nearby. If this is not possible then try to find the darkest spot you can. Man-made Light sources have an effect on the night sky by washing out the dimmer objects and they have an effect on your eyes by causing your pupils to close. This will decrease your ability to see the dimmer objects.

Beginning your observing is the most critical time for one big reason and this is why a lot of people don’t realize how rich the night sky really is. It takes your eyes up to a half an hour to fully adjust to the darkness outside. If you go outside and immediately begin looking for object in the sky you may be disappointed but this is because your eyes haven’t adjusted yet! Give it some time and let your eyes fully adjust and you will be amazed at how many more things you see in just a half hour time.

Equipment and stuff to bring along

Get some star maps, planet charts, and reference materials and bring them right outside with you. They will help you to find various objects. But it will be dark outside so you won’t be able to read them! And if you turn on some kind of a light or flashlight your night vision will be ruined. But there is a way to read your charts and materials without ruining your night vision. Cover your flashlight with some type of red cellophane or tape so it only gives off a dim red glow. The reduction in light will have less of an effect on your viewing and your eyes are very insensitive to red light so your pupils will not dilate. You can buy flashlights with red covers online, at astronomy and optical shops, or even at military surplus stores.

Star Maps

Suggested Materials List:
  •  Lawn Chair or Reclining Chair 
  •  Constellation Chart 
  •  Planetary Chart 
  •  Lunar Chart 
  •  Plenty of Warm clothing 
  •  Flashlight covered with red cellophane
  •  Snacks and hot beverages

Things to See

The first place you can start with is the moon (If it is out). And the best viewing will be when it is only a think crescent. This is because when it is like this the sun is casting light on it at a very sharp angle and the surface features will cast long shadows which makes them easier to see. With a full or near full moon the light hits the surface of the moon directly and casts no shadows.

The Milky Way Galaxy – Our solar system is part of a tremendous spiral galaxy called the Milky Way galaxy. You can see this galaxy as a band of diffuse light that stretches across the sky. It takes dark skies and well adjusted night vision to see it but it is quite a remarkable sight. Every star and constellation map will show you where the milky way stretches across the sky.

The Constellations – Finding and identifying various constellations can be a lot of fun. Each constellation represents an object, animal, or historic figure; and learning the story behind them can also be a lot of fun. Identifying constellations is also the only way to go deeper and find other objects like planets and comets. They form the background that everything moves within and they give you a frame of reference for finding these objects. Identifying constellations should be part of every star gazing event you undertake.

The Planets – The planets move around in the sky quite a bit and sometimes they are too close to the position of the sun which means they are not visible at night but five of the planets, when in the right position are easily visible with the naked eye. These are Mercury, Venus, Mars, Jupiter and Saturn. And often times these planets are the brightest objects in the sky. Refer to you planet charts to find current locations of them. One rule of thumb for figuring out whether something is a star or a planet is whether or not it twinkles. Stars twinkle and planets do not. So if you locate an object that you believe is a planet you can watch it for several minutes to see if it twinkles like other stars. If it does not then chances are good you have found a planet.

Colorful Stars – Stars are not all white. This is a common misunderstanding that people have. Stars come in a wide variety of brilliant colors and some of the more notable ones are the bright red Betelgeuse in Orion, the bright light-blue Rigel in Orion, the yellowish-white Altair in Aquila, and the bright red Antares in Scorpio. Finding and identifying these colorful stars can be a lot of fun. It can also be quite easy because some of the brightest stars in the sky are also very colorful from white to blue and red.

Some Objects of Particular Note

There are two very unique objects that are very easily seen with the naked eye on a dark night in the northern hemisphere. These are the Andromeda galaxy and the Hercules Nebula. They appear as tiny wisps of white smoke that look like small cotton balls. Once you start getting familiar with the constellations you should look for these two objects. The Andromeda galaxy is in the constellation Andromeda and the Hercules nebula is in the constellation Hercules.

Periodic and Occasional Objects

The night sky is filled with a lot of objects that come and go in different patterns. Some of them, like meteor showers, occur at around the same time every year. This is when the Earth passes through clouds of space debris. You can check a chart of meteor showers and plan an evening or several evening of watching them. Some meteor showers can give as many as 120 falling stars every hour.

Comets – These can be difficult to view because they are often very dim. But occasionally a comet will become very bright and be easily visible with the naked eye.

The night sky is more than just the moon and the stars. It is a extraordinarily rich environment with objects of all kinds. And given a little bit of time and dark skies you will discover and explore many of the beautiful secrets that it holds; and you can do it without a telescope. All you need is dark skies, a few charts, and a little bit of time.

Will Kalif

Source: Free Articles from ArticlesFactory.com
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