Astronaut Roberta Bondar shows us that space and conservation are 2 sides of the same coin: Bob McDonald

An unusual, limited edition coin issued by the Canadian Mint celebrates the flight of Roberta Bondar, Canada's first woman astronaut, aboard space shuttle Discovery.

The curved coin depicts Canada from space, and also show's humanity's impact on the planet.

Bondar was the first neurologist to fly in space, and spent eight days working with U.S.and European astronauts in Spacelab, a scientific laboratory that fit into the cargo bay of the space shuttle.

One of the first purely scientific missions in the shuttle program, theIMLtook place before the International Space Station even existed.

During her time in orbit, Bondarperformed more than 40 experiments looking at the effects of space flight on the body and brain, such as the disorientation astronauts experience when weightlessness removes our sense of up and down.

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But she also had time to gaze out the windows and see the majesty of our planet from the ultimate high perspective. And that changed her fundamentally.

A life-altering view

Upon returning to Earth, Dr. Bondar dedicated herself to conservation, publishing a number of books showcasing images of the Earth she took from space, as well as exotic locations around the world, including our national parks.

• Roberta Bondar photo exhibit opens

Her public speaking and events on environmental issues prompted the Canadian Mint to display a full colour image of Canada from space in the centre of the coin.

"My view from Discovery 25 years ago forever changed my view of Earth and instilled in me a commitment to protect this magnificent planet,"Bondarsaid upon the coin's unveiling.

But more symbolic is the other image of the Earth at night that appears when the coin is placed in the dark. It shows the eerie glow of cities spread across the continent. Our fires are visible from space.

That light shining upwards is light we do not use. We usually place lights on the ceiling so they shine downwards on our feet to let us see where we are walking. Any light that shines upwards is wasted energy. And when you look at the amount of light visible from space, it shows just how much energy we throw away.

And it's not just light.

We throw away energy, heat, water, even food. Curbing that wasteis one of the keys to tackling the issues around the human impact on the planet. If we could improve efficiencies and reduce what we throw away, it would be a huge first step towards cleaning up pollution and addressing climate change.

One problem is that we don't usually see our waste the way we see the glow of distant cities. Water just disappears down drains and toilets, our garbage is taken away, pollutants seem to be swallowed up by the oceans; out of sight out of mind.

Time to dim the lights

One stark example is the internal combustion engine that has been powering cars for the last hundred years or so. While today's engines are far cleaner and more efficient that those of the past, they are still only using about 20 per centof the energy in gasoline to turn the wheels. The other 80 per centbecomes waste heat that is taken away by the radiator and blows out the tailpipe.

To put it another way, if you put $40 into your gas tank, you only use $8 of that to drive down the road. The other $32 blows into the atmosphere along with a number of polluting gasses. But because we can't see heat, we don't think about that wastage. Electric motors, on the other hand, use almost all the energy put into them and they don't pollute.

If you see this new coin, think about the remarkable accomplishments of a Canadian role model, admire the beauty of our planet during the day, and think about the mark humanity has made on the planet that shines so brightly at night.

We can go a long way to dimming those lights.