What’s up there indeed? In this column, I’m going to talk about, um… nothing. Did that catch your attention? There are vast spaces between the stars and galaxies that appear to be completely empty, seemingly filled with nothing! Even our Solar system looks to be mostly empty space out past the Sun. It contains only a miniscule amount of material. When compared to the Sun, the planets and asteroids and meteors take up only a extremely tiny fraction of the space out there. Empty space reigns supreme… or does it?
In the 18th and 19th century light was considered a wave motion and this theory caused a great debate within the scientific and religious communities about what made up space. One side, initially the majority, favoured some sort of stuff or a medium since they reasoned that air waves needed air to travel and so, light needed something too. This medium was called ether or aether. Any other ideas, such as space was a vacuum, were considered absurd. Einstein’s first theory of relativity showed that light was quite content to travel through a vacuum and the ether theory was dumped. Space was declared to be an empty vacuum. That changed when spectroscopy became an accepted method of examining the wavelengths of light. It showed that intervening material, especially hydrogen, produced absorption lines. On average, one atom could be found in each cubic centimeter of space. The quality of a vacuum depends on where you are situated in outer space. Near a star, the Sun for example, there is a solar wind where a constant stream of atoms bumps up the quantity of atoms per cubic centimeter by a factor of about 5 or 6. The presence of a solar wind was confirmed by measurements taken from the early days of satellites. You can sort of see the presence of the solar wind when you observe the tail of a comet being pushed away from the comet by the Sun. Cosmic rays and neutrinos were soon added to the mix. Now throw in magnetic and electrical fields and gravity waves and space is starting to get crowded. In the 1930’s a type of energy called “vacuum energy” was first proposed. Dutch physicist Hendrick Casimir showed by experiment that 2 metal plates positioned very close together became very strongly attached. This was explained by the presence of “vacuum energy” outside the plates pushing them together. This energy arises from unimaginable numbers of particles and anti-particles briefly coming into existence and quickly vanishing. The entire universe boils with a vast quantity of energy. This may be the “dark energy” that scientists speculate is causing the universe to expand. So much for ‘empty’ space! I could describe much more to you about space and in greater detail but I’m afraid I’m rapidly filling up my ‘space’ for this column. I will close this discussion of what’s out there with a summary of what scientists have discovered about the make-up of space. It’s a truly astounding and fascinating description! To start with, if we could see with our eyes to the ends of the universe and added up all the stars and galaxies and Black holes and planets up there, that would be ‘normal matter’. It makes up only 4.9% of the universe. Not much, eh? Dark matter, which scientists have mapped and confirmed exists, makes up 26.8%. They have little idea of what it is, except that it has gravity and shapes the formation of galaxies and the structure of the universe. Finally, we have Dark energy. It provides the final 68.3% of the 3 ingredients that make up the recipe for our cosmos. In essence, all but 4.9% of the universe is a mystery – a land unknown and certainly not empty.
I have recently received several emails asking about a ‘bright star’ that can be seen in the west. This question often comes up. It is the planet Venus. It will reach maximum brightness, magnitude -4.8, on the night of February 16/17. Venus is the 2nd planet in the solar system and suffers from a run-away greenhouse effect. It has a temperature of 239 degrees C and an atmospheric pressure 90 times that of Earth at its surface. Add some sulfuric rain and it’s hardly a place for a pleasant stroll. It is known as the evening ‘star’ and also as the morning ‘star’. Why? Well, Venus orbits a bit more than 3 times for every 2 orbits of the Earth. Venus can therefore be seen at different angles to the Sun. Thus, it presents itself as an evening star for 9 ½ months, disappears behind the Sun and when it appears again, it becomes a morning star for 9 ½ months.
Have a look at Mars this month. It can be found in the constellation Pisces. If it weren’t for Venus, it would be the brightest object in that area.
Here are a few highlights for February.
Feb. 3: Quarter Moon.
Feb. 6: Earth at perigee – 366,675 Km.
• Full Moon. This is the Full Snow Moon. Usually the heaviest snowfall is in February (except for Winterlude when it usually rains on the canal – a bitter past experience). The snow makes hunting difficult so first nations called it the Full Hunger Moon.
• A Penumbral Lunar Eclipse occurs around 7:30 pm. The Moon will pass through the outer shadow of Earth (the penumbra) and not all of the Sun’s light will be blocked. This type of eclipse is difficult to notice but if you look closely, you see that the Moon becomes darker. Watch carefully.
Feb. 14: Watch for the Zodiacal light in the west after twilight during the last 2 weeks of February.
Feb. 15: The Moon passes 3 degrees north of Jupiter about 10 am. It might be bright enough to see. Around the 14th, Mars is close to Uranus and should appear within a 7X50 binocular field.
Feb. 17: Venus is at brightest high in the west.
Feb. 18: Last quarter Moon. Moon at apogee – 402,029 Km.
Feb. 20: The Moon passes 4 degrees north of Saturn.
Feb. 26: New Moon at 9:58 am. See if you can find it.
Feb. 27: Mars passes 2/3 degree north of Uranus. Try to see Uranus through your binoculars or a low power eyepiece on your telescope. From the 25th to the 27th they will be quite close.
Feb. 28 : The Moon passes 10 degrees south of Venus around 3 pm. Venus is so bright, it should stand out even though it is still daylight.
Keep looking up!
“The Beginners Observing Guide” by Leo Enright is an invaluable companion for adventures in the night sky. It contains star charts and is packed with information. It can be purchased at the Sharbot Lake pharmacy or it can be ordered from the Royal Astronomical Society of Canada at www.rasc.ca/publications. A subscription to our very own excellent Canadian astronomy magazine “SkyNews”, with its centerfold sky chart, can be ordered at the RASC site as well.
Clear Skies! Fred