Five Planets Visible

For the first time in a decade, if you are an early riser, you will be able to see all five of the naked eye planets in the sky. For the next month, just before sunrise, Mercury, Venus, Mars, Jupiter, and Saturn will be visible in the sky to the east. This sort of alignment can only be seen just before sunrise or just after sunset because Venus and Mercury can never be far from the Sun in the sky. Check out this post from July 16, 2014.

Remember, planets do not twinkle as compared to stars. So you should be able to easily spot the planets in the sky compared to the stars. Just for note, Mercury will be the planet closest to the horizon and Jupiter will be the farthest. The order of the planets in the sky will be Mercury, Venus,  Saturn, Mars, and Jupiter. If you have a powerful enough telescope, you also might be able to see Pluto near Mercury.

One other cool observation is beginning around the third quarter phase, the Moon will also be visible along with the five planets. As the Moon ages towards the New Moon, it will be among the planets in the sky.

Note: if you are really observant, you will be able to see a sixth planet. Comment below if you know which planet and why you will be able to see it.

Why Is the Sky Blue?

Believe it or not, we've actually discussed this before. When we've talked about reflection nebulae, we mentioned how the blue light is reflected towards our line of sight. In the same way, the sky is blue.

Remember, that light is composed of all colors of light. When light from the Sun enters the atmosphere, the dust in the sky easily reflects the blue wavelengths because they are shorter. The longer wavelengths (red, orange, yellow) pass right by the dust particles. The blue light is dispersed over the whole sky and when we look at the sky, we see blue. Of course, when we look at the Sun (which you should never do without proper eye protection), the Sun is yellowish (more yellow light in the Sun's spectrum than orange or red.

However, at sunrise or sunset, the sky around the Sun is orangish-red. Why is this? There are two reasons:

1.      The blue light is scattering away from our line of sight so all we see from the Sun are reds and oranges.

2.      The amount of atmosphere the light travels through to reach our eyes is more at sunrise and sunset than when the Sun is directly overhead. More dust (and pollution) for the blue light to interact with and be reflected away from us.