Showing posts with label space. Show all posts
Showing posts with label space. Show all posts

Friday, August 26, 2016

Earth-Like Planet Orbits Nearby Star

The recent discovery of an Earth-like planet orbiting Proxima Centauri confirms the speculation, in my free online novel 2052 - The Hawking Plan, that the three-star Alpha Centauri system is a likely target for preserving human life and civilization in the event a natural or man-made disaster wipes out life on Earth.

From CNN (24 August 2016):
... researchers have confirmed the existence of a rocky planet named Proxima b orbiting Proxima Centauri, the closest star to our sun, according to a new study. It is the closest exoplanet to us in the universe.

Given the fact that Proxima b is within the habitable zone of its star, meaning liquid water could exist on the surface, it may also be the closest possible home for life outside of our solar system, the researchers said.

Because of its location, the researchers hope it provides an opportunity for possible "robotic exploration in the coming centuries."

"The good news is that it is so close," study author Ansgar Reiners said. "It is not only nice for having it in our neighborhood, but it's a dream come true for astronomers if we think about follow-up observation.
My novel, 2052 - The Hawking Plan, as the title indicates, is set in the year 2052. I wrote it primarily as a vehicle to convey my predictions of "life, liberty, and technology in future decades." It was published in 2008. Here are the applicable excerpts:
“Stephen Hawking,” said Stephanie Goldenrod in a reverent tone, "The famous theoretical physicist and cosmologist who happens to be my great-grandfather, said, some fifty years ago, the human race will not survive on Earth for a thousand years. He wanted us to spread out, very fast, to Earth-like planets beyond our Solar System! He embraced human space travel!” As she said “Human space travel,” a video of Stephen Hawking floating in zero gravity appeared on the display wall.

She gazed at the video and smiled broadly. “Despite his physical limitations, my great-grandfather accepted an opportunity, in 2007, to fly in a special airplane that went to high altitudes and plunged to Earth to allow him to experience zero gravity in person! Unfortunately, by the time he passed away, human space travel had all but ceased, in favor of space probes ‘manned’ by intelligent robotic agents.

“He warned a natural disaster or human-made accident could wipe life out on a single planet."

I don't think the human race will survive the next thousand years.
Unless we spread into space.
There are too many accidents that can befall life on a single planet.
But I'm an optimist.
We will reach out to the stars.
[Stephen Hawking, Physicist and Cosmologist, 2001]

Animated charts appeared on the display wall behind her. “My Hawking Plan calls for nothing less than a massive effort to spread human civilization and genes far and wide throughout space. We’re talking about thousands of spaceships launched over a period of hundreds of years, starting by 2062, no more than ten to twenty years from today.”

As she spoke, a high-resolution satellite image of our TABB building in Orlando appeared on the display wall. Slowly the view zoomed out and all of the greater Orlando area filled the display screen. The view expanded to Florida and eastern North America, and then the entire Earth. A label appeared:

Mother Earth – Our Big Blue-Green Marble.

The image zoomed out further and faster to contain Venus and Mars, and then our Sun and Solar System. A label appeared:

Our Solar System – Our Planet Neighborhood.

The zoom-out ceased when our galaxy filled the screen. A label appeared: Our Galaxy – The Milky Way. The view shifted a few degrees and slowly started to zoom in on what, at first, seemed to be a single star. A label appeared:

Alpha Centauri – Our Nearest Neighbor Solar System. (Only Four and a Third Light Years Away).

As it zoomed in further Alpha Centauri morphed into two stars, one quite bright and the other a duller, reddish neighbor. Further zooming split the bright star in two, one whitish-yellow, and the other yellowish orange. Those two large stars, together with the tiny reddish one, made for a dramatic triple star-system.

The zoom-in slowed a bit and more detailed labels appeared. According to the text, the largest star was:

Centauri A – A Bit Larger and Brighter than Earth’s Sun.

It was in a binary partnership with:

Centauri B – A Bit Smaller and Duller than Earth’s Sun.

The smallest star was:

Proxima Centauri – A Red Dwarf.

The view panned between the three stars and then slowly zoomed in on Centauri A, showing a number of planets.

The zoom descended towards the fourth planet out from Centauri A – a “big blue-brown marble.” A label proclaimed:

Planet Hawking – Fourth Planet Out from Centauri A. (First Target for Extra-Solar Colonization).

A peninsula, similar to Florida, jutted out into the ocean. The zooming concluded with a satellite-like view of an area near the coastline. Inland were the foothills and a chain of lakes. A river flowed from the largest lake towards the ocean. The land was bare – no grass or trees – mostly brown, with some large areas of gray and black. The view morphed into a “live” video image.

As it panned towards the ground, a large hangar-like structure came into view. It was parked on a promontory between the river bank and the ocean beach. The hangar was surrounded by a park-like area of grass, bushes, and trees. Further zoom-in revealed the words:

TABB, Hawking 0001 (First Extra Solar System Human Colony, circa 2100).

The Hawking Plan logo, a stylized DNA molecule, was visible on the side of the hangar. Behind it could be seen a bright-yellow Sun, labeled: Centauri A. In the distance, lower in the sky and to the left, a second and duller-yellow-orange Sun, quite a bit smaller, was labeled: Centauri B. Far to the right and low in the sky a sharp-eyed observer could see a dull red Sun labeled: Proxima Centauri.

“The first step,” Stephanie continued, “Will be to use our authorized funding for internal studies augmented by ongoing TABB-funded university research. We need to define the parameters of human travel over awesome distances and extended times to reach well outside our Solar System. We must use our imaginations to their utmost limits to figure the best alternatives for spreading human genetics and civilization. Do we send living people, perhaps in suspended animation? Or, will it be frozen embryos to be thawed, gestated in artificial wombs, and raised and properly socialized by robot nannies? What about plants and animals? Not since Noah’s Ark has there been a task as far-reaching as our Hawking Plan.”
The novel outlines and considers three general concepts for exporting human life and civilization to an Earth-like planet. They are:

Noah’s Ark – live humans and a selection of other animals and plants in suspended animation.

Embryonic – frozen human embryos and a selection of other animals and plants. The embryos to be thawed and brought to term in artificial wombs and socialized by “nanny robots”.

Panspermia* – frozen or salted prokaryotic (bacteria) and eukaryotic (plants, animals) cells to be thawed and evolved to advanced complexity over several thousand years in robot run genetic engineering laboratories, using modern plant, animal, and human genome data as a starting point.

In the novel, the first two options are discarded due to ethical overtones of sending humans on one-way journeys to space knowing that many would likely perish.

The third, Panspermia (or, more properly, Directed Panspermia**), has no such ethical overtones. In addition, the target planet, while "Earth-like", would most likely be somewhat different from Earth. If it was larger or smaller than Earth, the attraction of gravity would be greater or lesser. The solar radiation spectrum at the surface of the planet would vary, depending upon the size and age of their Sun and other factors. There could be more ultraviolet, or less, and more infrared, or less. The atmosphere would likely differ somewhat in percentages of nitrogen, oxygen, and other gases, etc. Thus, the "Panspermia" plan starts with basic cells and intends to tailor the plant, animal, and human genomes during a 6,000 to 10,000 year period of "rapid assisted evolution", to better match actual conditions.

On the other hand, in the novel, some fiscally conservative opponents of the Hawking Plan note that the idea of planting bacteria, plant, and animal cells and using rapid assisted evolution to adapt them to a new home planet, contains echoes of the supposedly discredited theory of "Intelligent Design" to account for the origin of  life on Earth. Uh oh! Read all about it here: 2052 - The Hawking Plan

Ira Glickstein


[From Wikipedia]

*Panspermia (from Greek πᾶν (pan), meaning "all", and σπέρμα (sperma), meaning "seed") is the hypothesis that life exists throughout the Universe, distributed by meteoroids, asteroids, comets,[1] planetoids,[2] and, also, by spacecraft in the form of unintended contamination by microorganisms.[3][4]

Panspermia is a hypothesis proposing that microscopic life forms that can survive the effects of space, such as extremophiles, become trapped in debris that is ejected into space after collisions between planets and small Solar System bodies that harbor life. Some organisms may travel dormant for an extended amount of time before colliding randomly with other planets or intermingling with protoplanetary disks. If met with ideal conditions on a new planet's surfaces, the organisms become active and the process of evolution begins. Panspermia is not meant to address how life began, just the method that may cause its distribution in the Universe.[5][6][7]

The first known mention of the term was in the writings of the 5th century BC Greek philosopher Anaxagoras.[12] Panspermia began to assume a more scientific form through the proposals of Jöns Jacob Berzelius (1834),[13] Hermann E. Richter (1865),[14] Kelvin (1871),[15] Hermann von Helmholtz (1879)[16][17] and finally reaching the level of a detailed hypothesis through the efforts of the Swedish chemist Svante Arrhenius (1903).[18]
Fred Hoyle (1915–2001) and Chandra Wickramasinghe (born 1939) were influential proponents of panspermia.[19][20] In 1974 they proposed the hypothesis that some dust in interstellar space was largely organic (containing carbon), which Wickramasinghe later proved to be correct.[21][22][23] Hoyle and Wickramasinghe further contended that life forms continue to enter the Earth's atmosphere, and may be responsible for epidemic outbreaks, new diseases, and the genetic novelty necessary for macroevolution.[24]


In an Origins Symposium presentation on April 7, 2009, physicist Stephen Hawking stated his opinion about what humans may find when venturing into space, such as the possibility of alien life through the theory of panspermia: "Life could spread from planet to planet or from stellar system to stellar system, carried on meteors."[25]


** Directed panspermia concerns the deliberate transport of microorganisms in space to be used as introduced species on lifeless planets. Directed panspermia may have been sent to Earth to start life here, or may be sent from Earth to seed exoplanets with life.
Historically, Shklovskii and Sagan (1966) and Crick and Orgel (1973) hypothesized that life on Earth may have been seeded deliberately by other civilizations. Conversely, Mautner and Matloff (1979) and Mautner (1995, 1997) proposed that we ourselves should seed new planetary systems,
protoplanetary discs or star-forming clouds with microorganisms, to secure and expand our organic gene/protein life-form. To avoid interference with local life, the targets may be young planetary systems where local life is unlikely. Directed panspermia can be motivated by biotic ethics that value the basic patterns of organic gene/protein life with its unique complexity and unity, and its drive for self-propagation.
Belonging to life then implies panbiotic ethics with a purpose to propagate and expand life in space. Directed panspermia for this purpose is becoming possible due to developments in
solar sails, precise astrometry, the discovery of extrasolar planets, extremophiles and microbial genetic engineering. Cosmological projections suggests that life in space can then have an immense future.[1][2]

Wednesday, June 17, 2015

VISUALIZING: Einstein's "Miracle Year"

In 1905 an obscure, 26-year old Assistant Examiner in the Swiss Patent Office revolutionized the world of Physics forever. Albert Einstein published four ground-breaking papers in a single year!
LINKS TO RELATED POSTINGS AND RESOURCES
VISUALIZING Relativity - PowerPoint Show
VISUALIZING Relativity - Excel Spreadsheet
VISUALIZING for Science and Technology - Blog Posting
VISUALIZING Einstein's "Miracle Year" - Blog Posting
VISUALIZING My Insight Into Lorentz Gamma - Blog Posting
VISUALIZING the "Twin Paradox" - Blog Posting

1- PHOTOELECTRIC EFFECT

This paper may be considered the foundation of Quantum Theory. Einstein theorizes that Energy is not continuous, but rather comes in DISCRETE QUANTA.

2- BROWNIAN MOTION

Statistical physics.

3- (SPECIAL) THEORY OF RELATIVITY (INVARIABILITY)

Perhaps his most important paper, On the Electrodynamics of Moving Bodies, begins with a VISUALIZATION of a magnet and a coil of wire. He notes that, when the wire is held still and the magnet is moved, an electrical voltage is produced in the wire. The opposite is also true, he notes, when the magnet is held still and the wire is moved.

Einstein's critical INSIGHT was that it was the RELATIVE movement of the wire and the magnet that induced the electrical voltage.

He knew about electrical technology because his father owned a company that manufactured electrical equipment. However, by the 1880's, when Einstein was a child, many other people had this knowledge, yet, it was not until 1905, with this paper, that the critical implications of this simple VISUALIZATION were recognized.

Of course, by the time he had the insight and wrote this paper, Einstein had a diploma in Physics and Mathematics from the Zurich Polytechnic. That enabled him to extend his insight lightyears [pun intended] beyond mere electrical technology and clarify Maxwell's electrodynamics.

Einstein proposes two startling postulates:

1) "The same laws of electrodynamics and optics will be valid for all frames of reference." and
2) "Light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body."

These two postulates summarize the essence of Einstein's 1905 theory, which has come to be called his SPECIAL Theory of Relativity, to distinguish it from his later 1915 GENERAL Theory of Relativity. [Special Relativity applies only to so-called Inertial frames of reference moving at a constant speed, while General Relativity extends the ideas to frames of reference that are subject to acceleration, including the effects of gravity in the vicinity of a massive body. Some commentators including me (and even Einstein at one time :^) think these theories would have been better named the Special and General Theories of Invariability.]

The first postulate of Special Relativity establishes that ALL frames of reference are equal with respect to the applicability of the Laws of Nature. Some social commentators have, IMHO, over-interpreted the applicability of this idea, claiming that everything is relative,  including basic concepts of ethics. The actual meaning, IMHO, is the Invariability of the Laws of Nature, being the same to all observers, at all times and places.

The second postulate does away with the need for a "luminiferous ether" the then prevalent idea that light and other electromagnetic waves require a medium in which to propagate, the way sound waves require air, water or some other medium. Again, IMHO, some scientists have over-generalized that postulate to deny any concept of Absolute Space or Absolute Time. All Einstein says is that all attempts to measure the Speed of Light will yield the same value, which is another example of Invariability.

Quoting Einstein directly:
... the unsuccessful attempts to discover any motion of the earth relatively to the 'light medium,' suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest. 
and
...The introduction of a 'luminiferous ether' will prove to be superfluous inasmuch as the view here to be developed will not require an 'absolutely stationary space' provided with special properties, nor assign a velocity-vector to a point of the empty space in which electromagnetic processes take place.
Thus, while sound waves require a medium for propagation, light and other electromagnetic waves do not. For example, assume I am some distance from a wall and I make a loud, sharp sound (such as a gunshot), and then measure the return-trip time between the original sound and the echo, I will measure a shorter time in still air than I will if there is a wind blowing the air towards or away from me.

The reason for this is that, for still air, the outbound and return trip will take exactly the same amount of time, while, for moving air, it will take longer for the sound going against-the-wind, and shorter for the sound going with-the-wind.

You might think the longer and shorter changes would cancel out, but that is not so, The against-the-wind slowdown will be greater than the with-the-wind speedup. To VISUALIZE that, imagine the extreme case where the wind is blowing at the speed of sound. The with-the-wind sound will get there at twice the speed of sound, but, the against-the-wind sound will never get there!

Not so with light and other electromagnetic waves. The 1887 Michelson-Morley experiment demonstrated that there was no difference in the return trip time for light signals aligned with the 67,000 Miles per Hour motion of the Earth around the Sun and those at right angles to that motion.

Thus, there is no "ether wind", but there are differences between Kinetic (and Potential) Energy levels experienced by different Observers. 

IS THERE ANY SUCH THING AS ABSOLUTE SPACE AND TIME?

Consider the so-called "Twin Paradox", where the stay-at-home twin will have aged more than the rapidly-moving travelling twin when they are reunited. This has been explained by the fact the travelling twin changes frames of reference when he turns around to come back home. True, but, IMHO, the real difference is that the travelling twin has spent his life at a higher speed and thus a higher level of Kinetic Energy than his stay-at-home sibling, and thus aged more slowly.

Alternatively, imagine a stay-at-home twin who spends her life on the surface of a massive body, while her travelling sibling goes on a slow-speed journey to far-away empty space, living most of his life far from any massive body, and then slowly returning. Which will age more slowly? Well, in this case it is the stay-at-home twin! IMHO, the real difference is that the stay-at-home twin has spent her life at higher gravitational acceleration, and thus a higher level of Potential Energy than her travelling sibling, and thus aged more slowly.

OOPS! If you bought the above explanation you have to ask: "Higher Kinetic or Potential Energy with respect to what?" Well, at least with respect to his or her sibling! Higher Kinetic Energy is based on being at a speed that is greater than the speed of some reference point, is it not? Similarly, higher Potential Energy is based on being under the influence of gravitational acceleration that is greater than the acceleration of some reference point, is it not?

Thus there is some point (such as the Center of Mass of the Universe?) or points (such as Lagrange points L4 and L5?) that have lower Kinetic and/or Potential Energy levels than others, and are thus special in that residents will age more rapidly there. Perhaps there is a point (or points) in the Universe where aging is more rapid than ANYWHERE ELSE. At that (perhaps imaginary) point or points, residents experience Absolute Time (and/or Space) and are truly "At Rest" because they are at some Absolute Zero Kinetic and/or Potential Energy level.

[Note: Lagrange points, L1 to L5, are where the combined gravitational pull of two large masses provides precisely the centripetal force required to orbit with them. L4 and L5 are stable.]

4- EQUIVALENCE OF MATTER AND ENERGY
This paper is merely the source of the World's Best-Known EquationE=Mc2  


CONCLUSION

Four published papers. Pretty good work for a 26-year old in a single year - or a lifetime! 


Ira Glickstein 

Thursday, May 28, 2015

VISUALIZING: for Science and Technology

Computer Model Visualization of Crash-Dummy

Nowadays it is common to use computer models, such as the crash-dummy in the adjacent image, to help us VISUALIZE and better understand complex situations and systems. Prior to the advent of computer models, we had to use mental models in our "mind's eye", along with physical aids such as paper maps and diagrams, modelling clay, and other means.

LINKS TO RELATED POSTINGS AND RESOURCES
VISUALIZING Relativity - PowerPoint Show
VISUALIZING Relativity - Excel Spreadsheet
VISUALIZING for Science and Technology - Blog Posting
VISUALIZING Einstein's "Miracle Year" - Blog Posting
VISUALIZING My Insight Into Lorentz Gamma - Blog Posting
VISUALIZING the "Twin Paradox" - Blog Posting

Albert Einstein was a great physicist, with all the requisite mathematical tools. However, he rejected purely mathematical abstraction and resorted to physical analogy for his most basic insights. For example, as part of the thought process that resulted in his theories of Special Relativity (1905) and General Relativity (1915) he imagined himself riding along a beam of light; or as an observer standing along the tracks as a train zipped by at near-light-speed; or as a scientist sealed in a closed box and not able to tell if the box was stationary on the surface of the Earth, subject to gravity, or in deep space, far from massive objects, but subject to acceleration due to being dragged by a rocket at ever-increasing speeds.
VISUALIZING the Solution
Using Math and Graphics

Of course, Einstein and virtually all scientists and technologists use mathematical abstractions to quantify the meaning in our visualization models. We change the initial conditions and run these models to simulate what may or may not happen in different situations.

COMPUTER MODELS FOR VISUALIZATION

As personal computers and the Internet have become endemic, manual typewriters, paper maps, physical books, and so much else has been displaced by automated versions. Similarly, computer visualizations and models have displaced older methods - except for that old reliable "mind's eye" which remains as important as ever.

During my career as a Senior System Engineer at IBM and Lockheed-Martin I made extensive use of computer models and visualizations and have continued to do so since retirement.

In particular, I have created visualizations for the Atmospheric "Greenhouse" Effect and Einstein's Special and General Relativity. 

VISUALIZING THE ATMOSPHERIC "GREENHOUSE" EFFECT

As a Guest Contributor to the World's most popular Climate site, I authored a four-part series on Visualizing the Atmospheric "Greenhouse" Effect that attracted over 65,000 page views and over 2000 comments (see:  Physical Analogy,  Atmospheric Windows Emission Spectra, and Molecules and Photons,) The following graphics are some of the animated visualizations I created for that series.   


Physical Analogy

Model of a Physical Greenhouse
Model of the Atmospheric "Greenhouse"Effect

Modeled Down to Photons and Air Molecules































VISUALIZING EINSTEIN'S SPECIAL AND GENERAL RELATIVITY


Perhaps the most well-known equation in the world is E = mc2, recognized by virtually every person. But, what does it really mean?

And, many people know about the so-called "twin paradox", where one twin goes off on long mission at high speeds into space, and comes back younger. But why does this happen and exactly what causes it?

If "everything is relative" why isn't the stay-at-home twin also also younger? So, everything is not relative, and perhaps Einstein's original name for his theories "Invariance" is more apt -for the fact all observers, including those moving at different speeds, measure the same speed for light.

If the traveling twin is younger due to experiencing high speed and acceleration, then it is aging that has slowed down, not time, per se.

Furthermore, what, precisely, is TIME? And how is TIME united with SPACE to form SpaceTime?

When you Google any of this stuff you are quickly buried in equations and tensor mathematics that no one (even an engineer like me) can really understand!

Well, all this bothered me for most of my life until, back in 2012, I decided to answer Alan Alda's Flame Challenge "What is Time?" and produce a short video. In the research process for that project, I think I had a critical insight into TIME, SPACE, and RELATIVITY that may help you VISUALIZE this important scientific theory.

Time - the fourth dimension (2013 Flame Challenge) from Ira V Glickstein on Vimeo.

Since that time, I've continued to delve into Relativity and I've come up with what I think is a unique way to visualize and ... perhaps ... even understand it. The following images are screenshots from an Excel spreadsheet I created to provide myself (and you :^) a "hands-on" experience with the relativistic effects of high speed (kinetic energy) and high acceleration (potential energy), including time dilation, length contraction, and the curvature of SPACE and TIME. It is available free.


Free Excel Spreadsheet for VISUALIZATION of Einstein's Special and General Relativity. 

Image is of the Main Panel where user selects a Star, Planet, or Set Angle Option. In the case illustrated, the SpaceTime angle is set to 30º, where velocity is half the speed of light. This causes clocks to slow down by 13.4%, which corresponds to 49 days per year or 482 seconds per hour. Right side shows Special Relativity Effects due to the Kinetic Energy of moving at half the speed of light in empty Space. Left side shows equivalent General Relativity Effects, where Time "curves" due to the Potential Energy of being "at rest" close to a Black Hole.


Free Excel Spreadsheet for VISUALIZATION of Einstein's Special and General Relativity. 

Image is of the SpaceTime view of the right side of the Main Panel (where the vector sum of TRAVEL + AGING = 1) plus the Minkowski-Like SpaceTime view (where the simple sum of TRAVEL + AGING =1).  

Free Excel Spreadsheet for VISUALIZATION of Einstein's Special and General Relativity. 
Image is of the Minkowski-Like view (described above) compared to a Planck view, where both Space and Time are assumed to be discrete, and Each tiny cell is 1 Planck Time (tby 1 Planck Length (P).

THE MAP IS NOT THE TERRITORY!

As my principal PhD advisor, Howard Pattee, taught me, "The MAP is NOT the TERRITORY". That sage statement means that no model is exactly the same as the thing being modeled (else it would be the real thing.)

We make models because the real thing is too complex and difficult for us to visualize, or -like the Global Climate- is not readily available for us to experiment upon.


The MAP is NOT the TERRITORY !
Many a General (or football coach) has moved symbols around on a map of the field of battle, convincing himself and his staff of inevitable victory, only to find his opponent also had a model, perhaps a better one plus superior forces to carry it to victory. 

We generally model only the most important or critical parts of the situation or complex system we are trying to visualize. We consider the model to have been successful if the results match actuality to some level of fidelity, at least for those significant portions. If subsequent testing reveals that the model does not comport with reality, we must improve or discard it.

CONCLUSION

This is the first of what I believe will turn into a series detailing my VISUALIZATION of Einstein's Relativity. Please stay tuned!

Ira Glickstein

Wednesday, March 6, 2013

What is Time? Alan Alda's 2013 "Flame Challenge"


Time - the fourth dimension (2013 Flame Challenge) from Ira Glickstein on Vimeo.

My entry for Alan Alda's 2013 Flame Challenge was submitted last week. It is in the form of a short video  answering the deceptively simple question "What is Time?" (click above to view the video).

Alan Alda is on a mission to help youngsters become interested in science. In conjuction with the Center for Communicating Science at SUNY Stony Brook, he started the Flame Challenge in 2012 with the question "What is Flame?" They received some 800 entries.

I expect they will get even more this year with the question "What is Time?"

ABOUT MY ENTRY

I think I've come up with a unique way of viewing "Time - the fourth dimension".  Due to a strict limit on the length of the video, and the fact that it is aimed at 11-year old students, I have had to greatly simplify the material. This Blog posting includes additional material that will be useful to adult readers and science teachers who wish to know more about my way of viewing Time.

There are three big ideas here:
  1. TIME is NOT a clock (any more than Space is a ruler or Heat is a thermometer), nor is it rotation of the Earth or motion or the order of events, etc.  
  2. TIME is the fourth dimension, plain and simple. It appears different to us because the whole Universe is speeding along the Time axis at the speed of light.  
  3. TIME slows down when we move in Space because nothing can move faster than the speed of light, so any motion in Space must take away from the speed in Time such that the vector sum of the Space and Time velocities exactly equals the speed of light.
WHAT TIME IS NOT

Time is not the tick, tick, tock of a click, click, clock, any more than Space is a ruler or Heat is  a thermometer!
 
Nor is Time the rotation of the Earth on its axis that gives us day and night divided into 24 hours. Nor is it the movement of the tilted Earth in orbit around the Sun that gives us the seasons, nor any other kind of motion. Nor is it the spontaneous decay of certain atoms that give radioactive materials a half-life. Nor is it simply the ordering of events.

WHAT TIME IS

Time, plain and simple, is the fourth dimension, very much like the first three dimensions of Space.
 
The Time dimension appears different to us because you and I and the whole Universe are hurtling along it at very nearly the speed of light as a consequence of the “Big Bang” expansion some 13.7 billion years ago, in which our Universe, along with the dimensions of Space and Time, originated.

Since Time itself originated with the "Big Bang" it may not be meaningful to even ask the question "What happened before the Big Bang?" In any case, we may never know what caused it.
 
The Universe originated as an incredibly energetic and dense point of Energy/Matter that suddenly expanded. During the initial moments of the expansion, it is not clear if there was anything like the sub-atomic and atomic particles of Matter or the radiation of Energy with which we are familiar today. However, when Matter and Energy, as we know it, formed, all particles with mass were expelled along the Time axis, or at very tiny angles with respect to that axis. You and I, along with everyone and everything else, are still moving along or near that dimension at very close to the speed of light, c, which is as fast as anything can go.
 
We do not notice our ultra-rapid travel along the Time dimension as motion because the whole Universe is moving along with us. Therefore, we notice only relative motion between ourselves and other people and between ourselves and other things.
 
For example, people on the equator are happily unaware that they are moving Eastward at about 1,000 miles per hour due to the rotation of the Earth on its axis. Unless you live in one of the polar regions, you are moving Eastward at hundreds of miles per hour. Even if you are on an airplane, travelling  "Westward" from New York to Chicago or Los Angeles at 500 miles per hour, your net velocity is Eastward, due to the rotation of the Earth! We are equally unaware that the whole Earth is speeding along at over 67,000 miles per hour on its orbit around the Sun!
 
WHY TIME CAN BE SLOWED A BIT
 
We live in four-dimensional SpaceTime where everything must move at the speed of light, c, either along the Time axis, along a Space axis, or in a combination of Time and Space at an angle, Θ, to the Time axis. If movement is totally aligned with the Time axis, Θ = 0 and we are said to be “at rest” in Space, and we move along the Time axis at the normal rate (c, about one foot per nanosecond).
 
If we are not "at rest" in Space, Θ > 0, and we move through SpaceTime in a combination of Space and Time such that the vector sum of our Space and Time velocities is exactly c. Since nothing can go faster than c, any movement in Space must slow down our movement in Time. This was recognized over 100 years ago by Lorentz, Minkowski, and Einstein, who use the terms "Dilation of Time" and "Contraction of Space". This is usually expressed in terms of the Lorentz factor:
 \gamma = \frac{1}{\sqrt{1-v^2/c^2}} \,
where c is the velocity of light and v is the velocity of an object in Space.
As an engineer, I found that way of expressing relativistic effects of travel at significant fractions of the speed of light not to be "understandable" from my physical (and perhaps anal) point of view.

After knocking my head against the wall over an inordinate amount of Time, I finally realized that I could get an exactly equivalent Lorentz factor by considering the angle Θ, between the Time axis and the velocity vector of an object through SpaceTime.

[above image modified 12 April 2013]

It turns out that v (the velocity of the object in Space) divided by c is equal to the Sin Θ, and that 1/ϒ, the Lorenz factor, is equal to the Cos Θ.  

WHAT ARE DIMENSIONS?
 
This may sound like a simple question, and the answer is pretty simple, but, just to be sure we are all on the same page (see figure below):
 
0 - A POINT has ZERO dimensions
1 - Drag the point along the FIRST dimension ("x" of Space) and you get a LINE, that has ONE dimension.
2 - Drag the line along the SECOND dimension ("y" of Space) and you get a SQUARE (or rectangle) that has TWO dimensions.
3 - Drag the square along the THIRD dimenson ("z" of Space) and you get a CUBE (or rectangular solid) that has THREE dimensions.
4 - Drag the cube along the FOURTH dimension ("t" of Time) and you get a HYPER-CUBE (or hyper-rectangular solid) that has FOUR dimensions.


 
SUMMARY

When movement is a combination of Time and Space, and the velocity in Space is v, an object is moving through SpaceTime at an angle Θ, such that: v/c = SinΘ, and 1/ϒ (the Lorentz factor) = Cos Θ.

The figure below shows the situation for seven different values for the angle of travel through SpaceTime, from Θ = 0 to Θ = 90 .


Θ = 0⁰  [Sin Θ = 0.0000,  Cos Θ = 1.0000]   AT REST IN SPACE
For an object that is "at rest" in Space, Θ = 0. Even when an object is not moving along the Space axis, it is moving along the Time axis. Since everything in SpaceTime must have a speed of c, an object "at rest" in Space must be moving at speed c in Time. Note that for this condition, v/c = 0 and the Lorentz factor ϒ = 1. Note also that, for this case Sin Θ is equal to v/c and Cos Θ is equal to 1/ϒ.

Even the fastest rockets and satellites developed so far go only a tiny, tiny fraction of c. Therefore, for all practical purposes, the angle, Θ, is 0 (approximately equal to ZERO degrees). For example, the Earth is travelling around the Sun at a speed of 67,000 miles per hour, faster than any rocket, but that is only 0.001 % of the speed of light. At 67,000 miles per hour, v/c =  0.00001 and  Θ = 0.0000017⁰.

Θ = 15⁰ [Sin Θ = 0.2588, Cos Θ = 0.9659]    MOVING 26% OF c IN SPACE
An object is moving through SpaceTime at an angle of Θ = 15. It moves through Space at 26% of c and through Time at 97% of c. Note that for this condition, v/c = 0.2588 and the Lorentz factor ϒ = 0.9659. Note also that, for this case Sin Θ is equal to v/c and Cos Θ is equal to 1/ϒ.

Θ = 30⁰ [Sin Θ = 0.5000, Cos Θ = 0.8660]   MOVING 50% OF c IN SPACE
An object is moving through SpaceTime at an angle of Θ = 30. It moves through Space at 50% of c and through Time at 87% of c. Note that for this condition, v/c = 0.5000 and the Lorentz factor ϒ = 0.8660. Note also that, for this case Sin Θ is equal to v/c and Cos Θ is equal to 1/ϒ.

Θ = 45⁰ [Sin Θ = 0.7071, Cos Θ = 0.7071] MOVING 71% OF c IN SPACE
An object is moving through SpaceTime at an angle of Θ =45. It moves through Space at 71% of c and through Time at 71% of c. Note that for this condition, v/c = 0.7071 and the Lorentz factor ϒ = 0.7071. Note also that, for this case Sin Θ is equal to v/c and Cos Θ is equal to 1/ϒ.

Θ = 60⁰ [Sin Θ = 0.8660, Cos Θ = 0.5000] MOVING 87% OF c IN SPACE
An object is moving through SpaceTime at an angle of Θ = 60. It moves through Space at 87% of c and through Time at 50% of c. Note that for this condition, v/c = 0.8660 and the Lorentz factor ϒ = 0.5000. Note also that, for this case Sin Θ is equal to v/c and Cos Θ is equal to 1/ϒ.

Θ = 75⁰ [Sin Θ = 0.9659, Cos Θ = 0.2558]   MOVING 97% OF c IN SPACE
An object is moving through SpaceTime at an angle of Θ = 75. It moves through Space at 97% of c and through Time at 26% of c. Note that for this condition, v/c = 0.9659 and the Lorentz factor ϒ = 0.2558. Note also that, for this case Sin Θ is equal to v/c and Cos Θ is equal to 1/ϒ.

Θ = 90⁰ [Sin Θ = 1.0000, Cos Θ = 0.0000]      TIME STANDS STILL 
Light (and other forms of electro-magnetic radiation) move through SpaceTime at an angle of Θ = 90. Light moves through Space at 100% of c and, therefore, since nothing can go faster than cTime stands still. Note that for this condition, v/c = 1.0000 and the Lorentz factor ϒ = 0.0000. Note also that, for this case Sin Θ is equal to v/c and Cos Θ is equal to 1/ϒ. Anything with mass cannot achieve this speed in Space because it would take an infinite amount of energy to get it up to this speed in Space.
 
[ADDED 11 March 2013] In response to some skepticism about my contention that the whole known Universe is speeding along the Time dimension at nearly the speed of light, I did more research and found support from Brian Greene, Professor of Physics and Mathematics at Columbia U, who has been featured on the PBS Nova series. He writes:

“Special relativity declares a similar law for all motion: the combined speed of any object’s motion through space and its motion through time is always precisely equal to the speed of light” [Excerpt From: Greene, Brian. “The Fabric of the Cosmos.” Vintage Books, 2007. See http://www.pbs.org/wgbh/nova/physics/fabric-of-cosmos.htm for his PBS series.]

I have provided more detail in the first comment below.
Ira Glickstein