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ARE WE THERE YET? ACTIVITIES 1. The above article deals with very large numbers, can you find any examples of large numbers throughout The Telegram? 2. Look in The Telegram for samples of mathematical equations? 3. Can you find any information concerning large distances within The Telegram? For more activities go to www.thetelegram.com and click on What’s Up April - Mid May Shawn Martin, RASC, St. John’s Centre PLANETS Venus (magnitude –3.9) shines brightly in the westnorthwest during twilight, getting a little higher each week. Mars (magnitude +0.5) high in the southwest during evening. It's in Cancer, left of Pollux and Castor. Jupiter (magnitude –2.1) is low in the dawn. Look for it above the eastern horizon. Saturn (magnitude +0.7) is high in the southeast to south during evening. INTERNATIONAL SPACE STATION (ISS) SIGHTING OPPORTUNITIES (More than one minute duration) April 29/ 9:12 pm, 4 minutes in duration - look South West. April 30/ 9:37 pm, 4 minutes in duration - look South West. (From St. John’s and surrounding area’s) WARNING! When using a telescope or binoculars, always be sure NEVER TO LOOK AT THE SUN! This can cause serious and permanent eye damage. To be safe, always make sure the Sun is fully set below the horizon before going outside with your telescope or binoculars. H’S STAR MONT CH S I AR N TH T 0-4309237 W p en paper s. Open m in news S Point this month’s star chart toward North and match the stars with those in the real sky. ds Brought to you by major NIE partners O Throughout history, many major write great distances with fewer numbers. figures in science and philosophy Of course, the universe doesn’t stop there! Distances have discussed ideas concerning the scale of the universe. Most beyond this are so vast that astronomers need yet another understood that the Earth’s source of unit of distance measurement, for describing the immense light, the Sun, reflected off heavenly distances between stars and galaxies. This unit of bodies causing their illumination, measurement is called a light-year and is equal to the hence, the light would have had time to distance a beam of light travels in one year. So, how far is a travel through space in order to reflect off light-year? Well, considering a beam of light travels 299,792 of these objects. Early European astronomers, km/sec, then with a little quick math we would write: most notably Galileo Galilei (1564-1642), had tried many 299,792 kms x 60 (seconds) x 60 (minutes) x 24 (hours) x experiments to try and understand the nature of how fast 365 (days) = 9,454,240,512,000 kms in a year! = one lightlight could travel. It wasn’t until 1676 that someone was year (ly). successful, when a Danish Astronomer named Ole Romer Therefore, our nearest stellar neighbour, Proxima (1644-1710) analyzed his observations of Jupiter’s moon, Centauri’s, 40,275,064,581,120 kms distance divided by one Io, being eclipsed by Jupiter. light-year equals 4.26 lightRomer found that the predicted MILKY WAY GALAXY years away! If we were to fly eclipses lagged in time, and 2.5 million Light Years (LY) in a Jet plane traveling nongained time, based on the stop at 1000 kms per hour, it changes in distance between would take over 4,597,610 Earth and Jupiter, depending on ANDROMEDA GALAXY years to reach Proxima their orbits, proving light's Centauri! speed was finite. Romer’s friend, Dutch Scientist Are we there yet? Not Christian Huygens (1629 quite! Distances get even Proxima –1695), using Romer’s 4.2 Light Years (LY) more astronomical once you Centauri SUN information, was able to move into the realm of calculate the speed at which galaxies. Our own Milky Way light traveled. However, his galaxy is about 150,000 lightcalculation was based on an years across and contains inaccurate measurement of about 500,000,000,000 stars! Earth’s orbit, and so produced Our closest galactic an inaccurate value. Some years SUN Earth neighbour, the Andromeda later the American Scientist Galaxy, is 21 quintillion kms Eight light minutes Albert Abraham Michelson 1 Astronomical Unit (AU) away or, in other terms, (1852-1931) made the most 23,635,601,280,000,000,000 precise measurement of the BIG BANG kms! When you see the Illustration by: Shawn Martin 13-15 billion Light Years (LY) speed of light. Michelson Andromeda galaxy in a designed and built an apparatus telescope, or with your naked eye, you are seeing light that which was able to measure the speed of light with greater has travelled through space outside our own galaxy for accuracy than any other previous method. Based on his approximately 2.5 million years! experiments, he came to the conclusion that light traveled at 299,746 km/sec. We now have a more refined value for the Trigonometry and how the Earth moves in its orbit speed at which light travels, which is generally called c provides a most useful unit of meaurement, called the (“cee”), 299,792 km/sec. Once the speed of light had a parsec. If a star is observed against the distance numeric value it could be used to measure astronomical starry backdrop, and seen to move against that distances. backdrop by a tiny angle of one arcsecond (1/3600 of a degree) when observed half a year later from Armed with this information, astronomers were now able the other side of Earth's orbit, that star is “one to use “cee” to express three different units of astronomical parsec” away. “Parsec” comes from “parallax of distance measurement: an Astronomical Unit, a Light Year, one arcsecond”. This unit of measurement is and a Parsec. equal to 3.26 light-years or 30.8 trillion km. So, Considering that the speed of light, like any speed, is if we were to use this measurement to establish expressed in units of distance per time, we can time things to the distance for the Andromeda Galaxy, we E determine distances within our own solar system. For would write 76,772,136 parsecs. example, it has been determined that the Earth itself is only The speed of light may be finite, but our eight light minutes from the Sun. Astronomers call this universe is infinite! We may not know the full measurement an Astronomical Unit (AU); in other words, 8 scale of the universe but we do have a crude light minutes is about 143,900,160 kilometers. Just think, estimate of it. We can estimate its size based on driving your family vehicle non-stop at 100 km, would take looking back ‘in time’ to the "beginning" (The Big you 164.26 years to reach the Sun! This system of Bang). Astronomers believe that the Universe measuring works fine for our own solar system but for began some 13 - 15 billion years ago. So, the most describing larger distances it becomes very cumbersome.. distant objects that we can see are about 13-15 billion For example, our nearest neighbouring star, which is light-years away! That is 141,813,607,680,000,000,000,000 Proxima Centauri has a, distance that would be written as kms! Or, 141.6 Sextillion kms! Are we there NOW? 40,275,064,581,120 (40 trillion, 275 billion) kilometers Shawn Martin RASC, St. John’s Centre away or 279,707 AU’s! Using AU’s allows astronomers to You can contact the Royal Astronomical Society of Canada, St. John’s Centre, at www.rasc.ca/stjohns/ Newspaper In Education THE TELEGRAM