TRIP AROUND THE UNIVERSE

Lets see.

The Size of Our World

 (ANTARES – Diameter 500,000,000 miles)

Sun  Dia 1,390,000 KM.

Earth Dia 12,756 KM

Antares is a red super giant. It is approximately 800 times larger than our own Sun.

Lets accept the facts and limitations first. Nothing can move faster than the speed of light. If you've got a mass, whether you're a galaxy, a spaceship, a bullet or a neutrino, you're going to go slower than the speed of light. And if you don't have a mass, you're going to move exactly at the speed of light. No exceptions.

The farthest things in the Universe -- the things that emitted their light 13.7 billion years ago -- are 46.5 billion light years away from us now.

So how did this happen? Two things, one simple and one not-so-simple. The simple thing is that the Universe has been expanding this entire time. Imagine you've got an ant on a deflated balloon, and the ant moves at a rate of 1 cm/second. When the balloon is totally deflated, the ant is only 2 cm away from the top of the balloon, her destination. But as she starts walking towards the top, something inflates the balloon. As she walks towards the top, she notices that the balloon around her is expanding.

Imagine taking a trip at the speed of light. The "ultimate speed limit" according to Einstein's Theory of Special Relativity; c = 186,000 miles/sec = 300,000 km/s = 3 x 10 ¹⁰ cm/s (= 1 light-year/year). The effects of Special Relativity will have a profound effect upon space travel. Because mass increases as one's velocity approaches c, travel near the speed of light will be very expensive and will require spacecraft designs far different from those imagined on Sci-Fi TV programs. A phenomenon called time dilation, will cause space explorers travelling near the speed of light to age more slowly than their compatriots left behind on earth. For now we will ignore the details and set off on a journey to explore the Universe.

The Moon - 1.25 light seconds from the Earth. Current evidence suggests that the moon may have been blasted away from the earth about 4.5 billion years ago when a Mars-sized "planetesimal" collided with the newly formed Earth.

Venus - About 2 minutes away when it is closest, would take almost 15 minutes when it is on the other side of the sun. Venus was thought originally to be our "sister planet"; visible as the "evening star" or the "morning star". We now know that Venus has a toxic atmosphere with sulphuric acid rain and a greenhouse effect that keeps the planet boiling hot.

Mars - 4 minutes away on average. This picture, taken by the Hubble Space Telescope is a true color image showing the polar ice cap. A meteorite that originated from Mars and landed in Antarctica shows evidence for Life on Mars which may have existed over 3 billion years ago according to some NASA scientists. Scientists at UCSD's Scripps Institution of Oceanography dispute the claim of Martian life, however. Mars is considered the most hospitable place for life after the earth.

Jupiter is about 30 light minutes from the Sun (hence about 20--40 light-minutes from Earth depending upon the relative locations in orbit. Jupiter's Great Red Spot is a gigantic storm in the upper atmosphere. At right, Io , with its huge volcano erupting fumes of sulphur.

Saturn with its fantastic rings is about 1 light hour from the Sun. These are "false color" image from Voyager. Saturn's large satellite Titan is massive enough to have its own atmosphere, though probably too cold to support life.

Neptune - 4 hours away, is, until March 1999, the outermost planet in the Solar System due to Pluto's highly elongated orbit. Because Neptune receives less than one tenth of one percent of the sunlight that we receive on earth, astronomers had expected Neptune to be cold and dormant. Instead, Voyager 2 showed Neptune to have activity much like Jupiter, including the giant dark storm system shown here.

Pluto and its companion (satellite) Charon. Pluto is the smallest of the planets and has been considered for demotion to a minor solar system body. It is also the planet with the most eccentric orbit; it lies at an angle to the rest of the ecliptic. From about 1979 to 1999 Pluto was within Neptune's orbit, making Neptune temporarily the most distant planet from the sun.

Continuing our journey outward for nearly one year , we come to the Oort Cloud which may contain as many as a trillion comets. Comets are of particular interest to astronomers because they may be the most primitive objects in the Solar System, revealing much about the conditions when our Solar System formed. Recent comets include Comet Hale-Bopp Bright ice/rock nucleus, yellow dust tail and faint blue gas tail. Comet Halley A short-period comet, Halley passes near the Earth every 76 years.

Looking back at the Sun, our star - 8 light-minutes = 1.5x10¹³ cm = 150 million km = 93 million miles from Earth. The Sun is a very middle class star, unique only becuse of its proximity and importance to Earth.

The next nearest star is Alpha Centauri, a triple-star system visible from the southern hemisphere, four light-years away. As a measure of how empty space is, consider a model in which the Sun is represented by a large grapefruit; the Earth would be the size of a fancy pinhead ten paces away and the next grapefruit (Alpha Cen) would be in Cleveland! (n.b. a light year is a distance not a time. One light-year (l.y.) is the distance that light waves travel in a year = 1.0 x 10¹⁸cm, about 6 trillion miles.)

Before we get too cavalier about zipping around the Solar System at light speed lets remember how far beyond our current capabilities this is:

Solar System Travel
Speed		Time to Jupiter	Time to Saturn	Time to Alpha Centauri
Freeway Speed	75 mph	600 yrs	1200 yrs	38 million yrs
Jetliner Speed	500 mph	90 yrs	180 yrs	6 million yrs
Concorde Speed (Mach 2)	1350 mph	33 yrs	66 yrs	2 million yrs
Spacecraft Speed (Voyager)	40,000 mph	1.5 yrs	3 yrs	70,000* yrs

The Voyager Spacecraft, the most sophisticated space missions yet attempted by humans, took years to get to Jupiter & Saturn. As of 1999 May, Voyager 1 was nearly 6 billion miles from earth; it takes over 20 hours to send a signal and receive a reply. See where Voyager is now. ^*The Voyager Spacecraft are not headed toward Cen, by the way.

The Pleiades Star Cluster, The Seven Sisters of Greek Mythology (Suburu to the Japanese) 375 l.y. away, is a relatively young cluster of hundreds of stars with an age of about 75 million years. Most stars form in clusters like the Pleiades.

The Orion Nebula - 1500 light years, visible as the second "star" in Orion's sword. This gaseous nebula contains a younger cluster of stars (age ~ 1 million years). The hot young stars in the Trapezium near the centre are ionizing and heating the surrounding gas, causing it to fluoresce. Compare the above with a much longer exposure of Orion, showing the faint outer regions. The nebula sits on one edge of a cold, relatively dense molecular cloud, where star formation is occurring actively.

The Crab Nebula, about 6000 l.y. away in the direction of Taurus, is the remnant of a massive star that ended its life in a gigantic supernova explosion in July 1054. The glowing gas in the picture is the "star stuff" enriched in heavier elements (C,O,S, etc) produced in the nuclear fusion furnace at the star's core. At the center of the Crab Nebula is a pulsar --- a rapidly rotating, highly magnetized neutron star.

The Veil Nebula part of the Cygnus Loop, remnant of a supernova that occurred about 15--20 thousand years ago. As the explosive shock wave moves outward from the dead star, it ploughs up material from the interstellar medium, causing it to glow. The gas in the centre is heated to temperatures of millions of degrees and is a strong source of x-rays.

The Ring Nebula , about 5000 l.y. in the constellation Lyra, is the final death "hiccup" of a star like our Sun. The outer layers of the star are ejected as it runs out of nuclear fuel and the hot inner core causes the ejected gas to fluoresce. This final stage is called a Planetary Nebula, though it has nothing to do with planets. At the center of the planetary nebula is the small (R~R_earth) intensely hot (T~100,000K) cinder of the dying star - a white dwarf.

Globular Cluster -- Globular clusters are gravitationally bound clusters of millions of stars, formed in the very early history of our galaxy, 10--15 billion years ago. There are about 250 globular clusters distributed roughly spherically around the Milky Way.

Our Milky Way galaxy is a system of nearly a half a trillion stars. It is 100,000 l.y. across. The Sun is about 2/3 of the way toward the outer part of the galaxy disk.

The Large Magellanic Cloud with The Small Magellanic Cloud are satellite galaxies to the Milky Way. They lie about 150,000 l.y. away in the southern skies. The Magellanic clouds were first described to Europeans by the crew of Magellan's ships as they rounded the tip of Cape Horn. Part of the collection of galaxies known as the "Local Group".

The Andromeda Galaxy - 2 million light years. This galaxy and our Milky Way make up the dominant galaxies of our local cluster, "The Local Group". The Andromeda Galaxy, also known as Messier 31, is somewhat more massive than the Milky Way, but otherwise structurally similar.

Spiral Galaxy Messier 33 (M33) Another member of the Local Group of galaxies. With the Milky Way and Andromeda, the only three spiral galaxies in the Local Group.

The Local Group of Galaxies is our own small cluster of about 30 galaxies, dominated by the Milky Way and Andromeda.

M51 The Whirlpool Galaxy, located about 15 million light-years from Earth, is undergoing a tidal interaction with its companion SB galaxy. The beautiful spiral structure in M51 may be due to this gravitational interaction.

The Virgo Cluster of Galaxies (left) is the closest galaxy cluster to the Milky Way, about 50 million l.y. away. Virgo contains several hundred galaxies. Our local group is an outlying satellite of the Virgo Cluster.

The Hercules Cluster of galaxies (right) 650 million light-years from Earth is unusual in the number of spiral galaxies that it contains.

Quasar 3C273 -- Quasars are the most luminous objects in the universe, visible to distances of billions of light years. They are believed to be powered by a massive central black hole, perhaps 100 million to a billion times the mass of the Sun. It generates energy by accreting nearby matter. 3C 273 was one of the first quasars discovered; with a red-shift that corresponds to 15% of the speed of light , z = 15%, it is about two billion l.y. away.

Gravitational Lens A very massive object, such as this cluster of galaxies, can act as a gravitational lens. Light passing through the cluster from an object located behind it can be focused and amplified to produce one or more images of the background object. The four bright spots in the fore ground are lensed images of a spiral galaxy lying behind the cluster.

The Hubble Deep Field, the deepest space photograph taken to date shows galaxies billions of light years away, as they were when the Universe was only a fraction of its current age, believed to be 10--20 billion years.

Lets come back to Milky way galaxy now.

The arm of a galaxy such as ours, must turn fairly quickly to go full circle. The speed is 140 miles a second. That is about 140 times faster than the jets we think of today! In fact, if you think about how fast a jet travels across the sky, after a minute or two it is out of sight, right? Well, if it was traveling 140 times faster or 140 miles a second, then it would go across the sky and be out of sight in less than one second!

Have you ever thought of what it would be like to be in a vehicle that is travelling at 330 miles in one second? What would it feel like to do it? Well the point is, you are doing it . Right now . Your body is literally 10 thousand miles of real space away from where it was a minute ago ! What got us going this fast? The energy of the "Big Bang," sent everything moving from one centre point, outwards in all directions, this fast at the beginning of this visible Universe. And nothing is slowing it down. In fact all galaxies, including ours, is going outward at a speed which is getting a little faster every year! The farthest objects from us, that have been increasing in speed for 12 billion years, are now at the edge of the visible universe and have been estimated to be travelling at a speed that is about a third of the speed of light! And still due to be increasing for the years to come.

The average galaxy (above) takes 250 million of our earth-years to make just one complete rotation of itself. Our Sun has circled the Milky Way Galaxy about 16 times since it was created within and will circle about 16 more times before our Sun has extinguished itself. It is being considered that maybe a third of all stars in every galaxy, has planets encircling them. There are 60 Galaxies in existence for every person on earth right now. So in other words, if galaxies could be      "owned" (like houses) each of us could have 60 Galaxies given to us like someone giving every person on our planet 60 Frisbees.. and remember, each of those Galaxies would have 100-200 billion STARS circling within. Not to mention the number of even more PLANETS connected to each Star. Feeling rich? Please do !

The Universe is now about 14 billion years old. Our Sun was created within the Universe (inside our Milky Way Galaxy) about 4 billion years ago, or at a time when the Universe was two thirds of the current age. Our Sun is due to last another 4 billion years.. while the universe is due to last for a trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion, trillion (you get the idea here?) MORE YEARS after our Sun disintegrates! All the while producing billions of more Suns throughout billions of more Galaxies inside itself. So you see, the existing Universe, at 14 Billion years old, is only at a tiny, tiny fraction of the age that it will eventually become.

Humans do not have a good grasp of numbers like a million, let alone a billion , or a trillion . When contemplating a thousand compared to a million, or when comparing a million to a billion, or even a billion to a trillion, keep the following question and its answer, in mind :

If on the line below, point A marks (zero) and point B marks 1 billion: with this in mind, ask someone to mark a point somewhere on this line to estimate where they think the number 1 million would reside.

(zero)0=A...........................................................................................B=(1billion)           ( place a mark on the line above where you think one million mark would be ? )

You will find that most people make the mark for 1 million somewhere near the middle of the line. But in fact 1 million is merely a small fraction of 1 billion . To be exact, a million is 1/1000th of a billion . This means that the mark on the line above for 1 million is about as close to point A as you could get your pencil to mark! (One million would not even exist within the first dot on the line above.) Try this sometime with a friend. The same is true for making a line with a trillion, and putting on the mark for 1 billion, again it would be 1/1000th. Same for one thousand compared to one million.

Here is a neat way to look at the stars above. If you were so large a Being that the Sun and the Earth (including all of the actual space of distance between the two) could fit in the palm of your hand and you then decided to start walking, with such oversized Being strides (you would be walking 2000 times faster than the speed of light!), towards the next Star nearest to our Sun -you would need to walk for 19 straight hours without stopping through nearly empty space, before you would reach your destination to the next nearest Star. Most of the Stars you see in the night sky from earth, you would reach in 20-40 years of such walking. At that rate, would take you about 1,200 years of walking, through empty (except for some very sparse ancient star clusters kicked out of some galaxies) space without stopping, just to reach the first galaxy nearest to Milky way!

PLAY WITH THE MILKY WAY AS IF IT IS A FLYING DISC TOY!

If you could enlarge yourself enough to hold our whole Milky Way galaxy (all 200 billion stars) in your hand like a frisbee. Indeed it would be shaped just like a frisbee disc, however, it would also be much thinner. To flip the example around for you, I could also say it this way: If you could somehow shrink the entire universe around you, while you stay the same size and the Milky Way galaxy shrinks in front of you down to the size of a frisbee, and in the process of shrinking it down, you also kept all the relative distances the same for all the stars within the galaxy, then the "miniature galaxy" would be shaped like a frisbee, but would end up being thinner than a piece of paper!

More Interesting is, if you were able to hold the Milky Way galaxy in your hand, the nearest galaxy to you would be a walk of about 3 months away, and it would fit in your hand the same as the Milky Way would. And remember, there are about 250 billion more galaxies, similar to them. In that relative relationship of size, if you were able to hold the galaxy in your hand and start walking from one end of the Universe to the other end, it would take you about 1.5 years non-stop. ! You would have walked past nearly 200 billion galaxies to get to the edge. In this calculation, you would be taking steps that span 300,000 light years at a time! You would be taking a step in one second, that takes light ( travelling at 186,000 miles per second) 300,000 years to travel!

Want to see great views of galaxies in action where just one revolution would normally = 250 million years?
Then grab your Frisbee disc and start Heaving H.O.E.
(Heaven On Earth !)