Our universe is more than 13 billion light years across, and within it is the Milky Way galaxy. This is where our solar system is located. Scientists ask themselves what created the universe, how does it work, and why does it look like it does, but they have just started to scratch the cosmic surface with new discoveries being made every day! Even within our own solar system there are new discoveries as we launch more probes and more people start to use telescopes. We can see the whole house, but we have yet to cross through the doorway when it comes to the exploration of the universe.

Solar System

If the Sun where the size of a basketball, the Earth would only be a tiny 2 millimeter dot! Most of the matter in the solar system is the Sun, which equates to about 98% of it. The other 2% is made up of planets, moons, asteroids, and dust. Our solar system has seven other planets besides Earth: Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune. There are four planets that are rocky and made of mostly solid material Mercury, Venus, Earth and Mars. Those planets are also the closest planets to the sun. The outer four planets are gas giants and are made mostly of gases. The largest planet in the solar system is Jupiter which has a giant red spot on its surface, which is a 200 year old raging storm that can fit three Earths!

There are at least 146 moons in the solar system; all of the planets have moons except for Venus and Mercury. The largest moon in the solar system is Ganymede, which is one of Jupiter’s 64 moons. The solar system has 5 dwarf planets: Ceres, Haumea, Makemake Pluto and Eris, which are all located in the outer reaches of our solar system called the Kuiper belt. The Kuiper belt is just beyond Neptune and is home to many icy asteroids that sometimes come in the inner solar system and orbit the sun which are then called comets. The Kuiper belt is larger than the asteroid belt, but is hard to see because it gets a very small amount of sunlight. There are, however, hundreds and thousands of asteroids that we can see clearly see in the asteroid belt between mars and Jupiter. Some of these asteroids can be as large as a mountain! A small free floating rock in space is called an asteroid. An asteroid that has entered the Earth’s atmosphere is called a meteor, and if the meteor hits, then it’s called a meteorite.

Deep Space

Deep space is home to some of the most interesting things in the universe and it is also very large – so large that we measure it in light years. A light year is not a measurement of time but of distance; it is the distance light travels in one year. Nothing is faster than light and the top speed of light is always 186,282 miles per second, or 6 trillion miles in a year.

Deep space is filled with a lot of interesting things, but if you were to look through a high powered telescope you would only see blobs of light. Those blobs of light are actually galaxies which are filled with of billions of stars! There are billions of galaxies in the universe so you would see these blobs everywhere you looked through the telescope. Galaxies are huge our Milky way galaxy is about 100,000 light years across!

In the telescope you would also see very bright stars and clouds of light. Those bright clouds are nebulae, or star nurseries, which are made of the following elements: hydrogen, helium and dust. A nebula can also be the death of a star that has exploded into space due to unstable gravitational forces. Nebula is the name given to clouds of gas that give off light. In the past galaxies were once called nebulae, because they looked like clouds of light and we didn’t know what they were yet.

In your telescope you might come across stars that are flying past and orbiting a single point in space. You look night after night and you never see what the stars are actually orbiting. If you saw this in a telescope you would be observing a black hole. A black hole is a star that has collapsed on itself due to its massive size. Nothing can escape a black holes’ event horizon, not even light, which is why you wouldn’t be able to see what the stars were orbiting.

Space Exploration

We may not be able to travel the speed of light yet, but we can still travel into space using rockets. We use space shuttles to travel into space and we once used them to travel to the moon. After completing the International Space Station (ISS) all NASA shuttles were retired after 30 years of service, and we now use other space agencies shuttles to get to and from the ISS.

We started to explore the moon in the late 1960’s and 1970’s to find out its origin, and subsequently ours, too. We have brought back more than 800lbs of moon rock to study from the Apollo missions and have learned that the moon had a volcanically active past. Before we went to the moon, the circular objects on the lunar surface were speculated to be volcano cones from a once volcanically active moon. Since we have landed on the moon we now know that they are mostly craters made from meteorites impacting the surface.

We have never sent a man to Mars; however, we have sent unmanned remote controlled rovers to investigate the surface. Scientists have found out that there is no liquid water on the surface and that the atmosphere is mostly made up of carbon dioxide. Mars is a cold desert reaching below -100 degrees Fahrenheit with zero precipitation. While there is no liquid water on the surface the Mars surface rovers Spirit and Opportunity may have detected traces of an ancient ocean.


Since the universe is so massive, and we will not be able to travel to the stars anytime soon, we use our eyes and technology to watch and learn about space. Our eyes have the ability to detect light waves and we use telescopes to enhance that ability. We use special telescopes to view deep into space like with the Hubble Space Telescope and into light spectrums we couldn’t normally see with the naked eye.

If you don’t have access to a telescope you can still observe the universe around you. Every star in the night sky has a name and follows a set path night after night. Ancient sailors relied on stars to navigate the sea at night and gave the star groups names – they also told stories about them, too. Constellations are groups of stars that make up perceived images like the following: Taurus, a bull; Scorpio, a scorpion; and Orion, a hunter.

Some events are easier to see, like the phases of the moon. Every 29.5/4 days the moon starts a new cycle with phases in each cycle. There are four very distinct phases of the moon: first quarter, full, last quarter and new. The ancients would use the phases of the moon each month to hunt, plant and harvest. However some of the things the moon did confused ancient people. During a solar eclipse the moon blocks out the sun completely and in a lunar eclipse the Earth blocks all sunlight from the moon making it dark. Our moon is the only one in the solar system that blocks out the Sun completely on a portion of the planet’s surface.