Science | Skywatch with Bill Irwin

By Bill Irwin –

I suppose, like your parents waiting up when you’ve been out late, it’s time for us to have that little talk about Mars.

As a reader of this column, you’ve probably wondered what it might be like to stand on the surface, however briefly, and with some life support, of course.

There would be a sky, because Mars still retains some atmosphere, but things would be stark and lifeless, like some remote desert on Earth. Mars has only one tenth the mass of Earth, so it hasn’t been able to retain the atmosphere it once had.

The sun would have about 70 per cent of the diameter it has here. It might feel like the warmth of a hazy day when the sun is very low in mid-January. Since the air would be very thin, a thousandth of Earth, there wouldn’t be much wind chill. You would need twice the solar panels (so I would get more work.)

Since the gravity is only 38 per cent of Earth, you would be an Olympic athlete at running and jumping or javelin throwing, things taking longer to fall back to ground. If you ran headlong into something, however, the impact would be the same, since your inertial mass is unchanged. So, don’t try it. A boxing match would be very interesting.

It takes Mars about 1.8 Earth years to go around the sun, so fewer birthdays, a boon if you have a large family. She probably wouldn’t appreciate those rare Martian meteorite earrings as much up there.

The day is nearly the same length, however.

To be there for any length of time would be hazardous. Mars does not have a molten iron core like Earth does, the differential rotation of which generates the Earth’s magnetic field and protects us from solar and deep space radiation. You would have to spend most of your time in underground or heavily shielded bunkers and watch the sun’s weather closely, to be able to hide from radiation storms.

The low gravity, while fun at first, would cause your muscle and bone mass to atrophy. You wouldn’t like it.

I don’t know if you can still sign up for Mars One; I’m going to pass on it.

This is a year when Mars comes close, the Earth catching up to it in its orbit. Opposition is on July 27 and Mars will be at its best for a month or more on either side of that date. There is a 17-year cycle of close and more distant oppositions, since the orbit of Mars is eccentric. This year will be a close one, with the planet subtending twice the diameter of a distant opposition. That means four times the surface area to look at, so more detail can be seen. Offsetting that, is the fact that close oppositions are low in the sky, this year in Capricorn. The turbulence of Earth’s atmosphere takes a heavy toll on objects that low in the sky. It can be like trying to look at something through a candle flame.

Fortunately, there are moments when the air settles and you can make that connection with the solid surface of another world. The reality of that observation is what it is all about for us backyard observers.

The less than dark skies around summer Solstice are not a hindrance to planetary observing.

There was a Mars hoax that came up around the time of the very close opposition in 2003, which may still be circulating on the internet. It said Mars would appear as large as the full moon in the sky. There is some information missing there, however. The statement originally said Mars would be as large as the full moon to the naked eye, when viewed thru a telescope at 60x magnification, which is true. Practically speaking, the moon is much brighter than a magnified Mars, so I would typically use 250-300x to get that much detail. That is pretty demanding, optically. Fortunately, the equipment here at the observatory is up to the task.

I certainly welcome my readers to come and see for yourself. There is no charge. Amateur astronomy is, for the most part, a freely given look into something that is your heritage. We have a campsite and a creature comforts heated tent/cabin adjacent to the observatory if you want to spend the night.

As usual, you can come right down to the arena here at the Bells Lake Observatory. Contact me at (250) 620-0596 or irwin8sound@gmail.com.

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