As the May becomes June, the planets will get closer together, Saturn and Mars most notably.  All three will meet up in a beautiful triangle in August.  By the middle of May, a Waxing Crescent Moon will join Venus in the sky.  Over the remainder of the month, it will visit the other two planets as it makes its way towards a Full Moon on May 27, 2010.  Looking to the north, we see the mother bear, Ursa Major, high in the sky.  She protects her cub, Ursa Minor, sitting about half way between her and the northern horizon.

Jupiter and Mercury rule the mornings over the next few weeks.  Mercury will be most visible on the 26th  of May when it is the farthest West of the Sun that it gets to in its orbit.  But the sky will be dominated by brilliant Jupiter, sitting in the southeast at sunrise.  The Moon visits Jupiter on June 6th, and might just barely be visible with Mercury on June 10 th as an extremely thin Waning Crescent.

This time of year is also a great time to go out and look for the Milky Way.  It is a cloudy band of stars that stretches across the sky.  Best visible after midnight, the brightest parts of our galaxy will rise in the southern sky between the constellations of Scorpius and Sagittarius.

Any time of the night, there are wonders to see in the sky.  So, while you are out camping or just standing in your drive way, make sure you look up and see the sights.

The solar system is our star, the Sun, and everything that orbits around it. The Latin name for the Sun is Sol. That is why it is called the solar system. What objects orbit the Sun? At last count, there are 8 planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune) and 5 dwarf planets (Ceres, Pluto, Eris, Makemake [pronounced MAH-kay MAH-kay] and Haumea). All of these except Mercury, Venus, Ceres and Makemake have one or more moons orbiting them. There are also innumerable asteroids and comets that orbit the Sun, but no stars.

The solar system is very different from a galaxy. A galaxy is a huge collection of stars bound together by gravity. The Sun is 1 star among 100-400 billion stars in the Milky Way galaxy. Are there other “solar” systems (more properly called stellar systems) in the galaxy? Yes. Astronomers have discovered hundreds of other stars that have planets orbiting them. Most of these newly discovered planets are Jupiter-size, as they are the easiest to find. NASA’s Kepler Mission is now searching for Earth-size and smaller planets orbiting other stars. After its mission concludes, we should have a good estimate of about how many of the stars in our galaxy have planets.

The Universe is everything we know of. It contains hundreds of billions of galaxies.

These are such big numbers that it is hard to comprehend them. Here is an example that might help. If you received $1,000 per day, how many days would it take until you had $1 million? The answer is 1,000 days, which is about 2.7 years. Now, for the billion dollar question. If you received $1,000 per day, how many days would it take until you had $1 billion? The answer is 1 million days. How many years is 1 million days? Try to figure it out before reading ahead… is it 5.4 years? 27 years?

The answer is 2,738 years! A billion is a REALLY big number. Remember, the Milky Way has over one hundred billion stars. That’s a hundred times bigger than a billion! If you could catalog 1,000 stars a day for 2,700 years, you would have cataloged less than 1% of the stars in our galaxy. That’s why astronomers should have job security.

There are several galaxies that are good candidates for the farthest-known galaxy, but what they all have in common is they’re roughly 13 billion light years distant. That means that when astronomers see these galaxies they’re seeing light that has been traveling for about 13 billion years.

It’s amazing to see something that far away because the universe itself is only 13.7 billion years old. We’re seeing the way this galaxy looked less than a billion years after the universe began. These photons of light have been in transit for 95% of the age of the universe.

A quick note about galaxies: We live in a galaxy called the Milky Way. It’s a giant, slowly spiraling collection of about 200 billion stars and it measures about 100,000 light years in diameter.

Our Sun is an ordinary star located about 30,000 light years from our galaxy’s center.

Our Milky Way Galaxy

Our nearest galactic neighbor is the Andromeda Galaxy. It’s slightly larger than the Milky Way Galaxy and is located 2.5 million light-years from us. It’s a favorite target for amateur astronomers and is the most distant object visible to the unaided eye. You’ll notice a lot of stars surrounding the Andromeda Galaxy in the image below. Those stars are the stars of our Milky Way Galaxy in the foreground, only a few hundred or thousand light years distant.

Andromeda Galaxy - Galactic Neighbor

Not all galaxies are beautiful spirals, but the Milky Way and Andromeda Galaxies are.

To appreciate how far away the most distant observed galaxy is, it will help to make a scale model.

If you shrunk the Milky Way Galaxy down to about the size of a salad plate (about 7 inches), then the Andromeda Galaxy becomes the size of a dinner plate roughly 12 feet away.

Scale Model: Milky Way Galaxy to the Andromeda Galaxy

2.5 million light years shrunk down to 12 feet. Intergalactic distances within a small room. Wow, that’s quite a cosmic crunch.

Now that you’ve got that kind of scale in mind, you can begin to appreciate just how far away the “farthest” galaxies are.

At the scale we’ve just created, the farthest galaxies are twelve miles away. That’s the distance from downtown Salt Lake City to Sandy.

Downtown SLC to Sandy - 12 Miles - Scale Distance to Farthest Galaxies

And what’s in between?

To answer that question – try thinking about this:

Imagine you’re looking at a region of space as empty as any you’ve been able to detect. You’ve chosen a tiny black bit of the night sky near the Big Dipper that’s only the size of a grain of sand held at arm’s length.

Now imagine that you’ve got the Hubble Space Telescope available to you, and you ask it to stare at that tiny speck of empty space for about ten days, non-stop.

What does the Hubble Telescope see in that “empty” bit of space the size of a grain of sand at arm’s length?

This:

Hubble Space Telescope Deep Field: An image of "empty" space

Everything you see in this image is a galaxy, each containing billions of stars. Some of these galaxies are only a few hundred million light-years distant. Some are billions of light-years from us.

One more time, that’s an image of a piece of “empty” sky the size of a grain of sand held at arm’s length. It turns out that deep space looks like this in all directions. Galaxies everywhere. The current estimate is that there are something on the order of 100 billion galaxies in the universe.

So, does it really matter how far away the farthest galaxy is?