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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
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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.
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Point this month’s star
chart toward North and
match the stars with
those in the real sky.
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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/
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