Measuring The Speed of Light

More than a measure of distance the speed of light is a measure of time – once that makes sense, a light will shine on the cosmos. Most of us have experienced mind drifting time outs, that perceptible moment of realization when eyes glaze as confusion sets in – light speed exasperation needn’t be one of them.

Light travels at 300,000 kilometers per second – multiply the number of seconds in a year by distance light travels per second and you have a light year – approximately 9.5 trillion kilometers. Such daunting distances lend themselves to glassy eyes, so astronomer Robert Burnham Jr. devised the measure of AU (Astronomical Unit – 1 AU being 150 million kilometers, or the distance from Earth to the Sun ). One AU is about 8 minutes – the time it takes sunlight to reach Earth. One light year is equivalent to 63,000 AU. By mind blowing coincidence, there are 63,000 inches in a mile.

Scaling the astronomical unit at one inch, here are distances to various stars, star clusters and galaxies:

Alpha Centauri: 4 miles

Sirius: 9 miles

Vega: 25 miles

Fomalhaut: 25 miles

Arcturus: 37 miles

Antares: 600 miles

Pleiades open star cluster: 440 miles

Hercules globular star cluster (M13): 24,000 miles

Center of Milky Way galaxy: 27,000 miles

Great Andromeda galaxy (M31): 2,300,000 miles

Whirlpool galaxy (M51): 37,000,000 miles

Sombrero galaxy (M104): 65,000,000 miles

Distance established, what about time? Brian Cox of BBC’s Wonders Of The Universe said – “the speed of light is the speed limit of the universe, built into the very fabric of space and time”, “the further away an object is, the further back in time we see it”. Starting to glaze over? Relax, take a deep breath, spend 3 minutes watching this video. I promise you’ll feel better –

Pondering Light Years

Technology capable of imaging cosmic formations at unattainable distances from Earth, led to pondering light years. Most everyone knows the terminology, understanding at some level the vast, unimaginable scope of our universe. I find myself wondering how many actually comprehend the magnitude of a light year. In the spirit of imagination and wonder – my armchair grasp of light years….

Light reigns as “fastest” in the known universe – 186,000 miles per second to be precise. To put this in perspective, in a single second traveling at the speed of light you would circle the equator 7.5 times. Multiplying the number of seconds in a year by the speed per second, you would have to cover 5.88 trillion miles in a year. Putting close to 6 trillion miles a year in perspective is mind numbing. Try picturing a light minute – it takes about 8 minutes for sunlight to travel 93 million miles to Earth. Visualize 525,600 minutes in a year, ponder 8 of those minutes evaporating in 93 million miles to the Sun.

American astronomer Robert Burnham Jr. published Burnham’s Celestial Handbook in various forms between 1966-1978. Burnham popularized the astronomical unit or AU. One AU = 93 million miles and/or 8 minutes of light speed. Coincidentally the number of AU in a light year and inches in a mile happen to be 63,000. All you have to do now is draw a mile long line in the sand to represent a light year – one inch of that line is the distance to our sun.

Extend that mile long line to slightly over 4 miles, you’ve arrived at Alpha Centauri, the closest star system to our own, 276,000 times the distance from Earth to the Sun. If modern technology attempted the 4 light year road trip to Alpha Centauri – it would take well over 100,000 Earth years.

Ponder 26,000 light years to reach the centre of our Milky Way galaxy, estimated to be over 150,000 light years wide. The Andromeda galaxy is 2 million light years away.

Contemplating light years is heady stuff. The next time you gaze at night’s sky, take a moment to wonder. Ask yourself how  long it took for starlight to cross the cosmos.

Our Little Corner of The Universe

Pondering our place in the universe is difficult – comprehension relies on points of reference. Take our sun – sure it’s a star yet we would never call warmth or light “star light” – stars are something a child wishes upon, they live outside the realm of sunlight. We feel the sun’s warmth, watch it rise and fall, take it for granted as air and water. Our sun is tangible, we see it every day – grasping what lies beyond our little corner, visualizing the universe in all its enormity without blowing a fuse – that’s the tricky part.

“Baby steps” elude when discussion of universal scope enter the ring. That said – I’ll give it a try. On a clear night, away from city lights with a dark sky void of moonlit interference – systematic dedication might result in counting 8 or 9 thousand stars. A friend shows up with respectable binoculars and perhaps 200,000 is possible.  A good backyard telescope materializes and upwards of 15 million stars blow your mind. In reality – our Milky Way galaxy is home to over 300 billion stars.

Ours is an average sized galaxy – measuring about 120,000 light years from end to end, ( one light year is approximately 9.5 trillion kilometres). Astronomers estimate over 170 billion galaxies in the “observable” universe – stretching outward from us for 14 billion light years in every direction.

Professor Marshall McCall of York University published a “map” of  galaxies within 20 million light years of planet Earth.

Image credit: Marshall McCall / York University

View larger. | A diagram showing the brightest galaxies within 20 million light years of the Milky Way, as seen from above. The largest galaxies, here shown in yellow at different points around the dotted line, make up the ‘Council of Giants’. Image credit: Marshall McCall/York University

The universe can’t be defined – exceeding imagination being the only definition I can offer. All I ask is that you “look at the damn sky” and at least try.

WR 104

The eve of Dec. 21 seemed an appropriate time to toss a death star into the mix. Tomorrow’s solstice just happens to coincide with an extremely rare galactic alignment. Every 25,800 years the sun and earth align with the centre of the” Milky Way”. It just so happens that the pesky constellation Sagittarius is part of the equation. Sagittarius; smack dab in the middle of the alignment, harbours some serious pondering.

The fact that Sagittarius is my sign has nothing to do with its mystery.

Sagittarius just so happens to end up in the spot light. For starters, the only unconfirmed radio signal from space, known as the “wow event” came from Sagittarius. Sagittarius is front and centre in the “galactic alignment”, and it happens to be the place WR 104 resides.

WR 104 is 8000 light years from earth. Discovered in 1998, it is actually 2 binary stars locked in orbit with each other. Known as a Wolf-Rayet system, WR 104 capable of causing serious trouble. Wolf-Rayet (WR) stars are on their last leg; burning thousands of times hotter and faster than our sun, they hurtle towards an inevitable super nova.

Aside from the black hole created when a star collapses, the nasty Gamma Ray Burst (GRB) is of greater concern. Picture a death ray of radiation obliterating anything in its path. A GRB would destroy our ozone layer; earth would be defenceless against cosmic radiation.

Scientists debate our chances of being at the receiving end of WR 104’s wrath. They all agree that earth has most likely experienced  GRB’s in the past. Either way; rather than disappoint the doomsday set when the Mayan prediction turned out to be a bust – ponder the death star. As my son once said – “there’s a million ways to die out there”.


Kepler 22b

Six hundred light years from Earth in the constellation Cygnus, circling a star named Kepler every 290 days, orbits the planet Kepler 22b.  Named for the NASA probe Kepler, this is the first confirmed “earth like” planet in a “habitable” zone. the habitable zone is defined as a planet just the right distance from its Sun to support liquid water.
 Kepler-22b -- Comfortably Circling within the Habitable Zone