Personal Radio

Poor Pluto. Discovered in 1930, it was only considered a planet for 76 years, before being "downgraded" to Dwarf Planet status. Most of us would be hard-pressed to name ANY of the other Dwarf Planets.

Pluto is smaller than the Earth's moon, but itself has five known moons.

Plutos' orbit is erratic, and sometimes it is closer to the Sun than Neptune.

In 2015, the New Horizons spacecraft flew by Pluto and took a few snapshots.

Poor Pluto. Discovered in 1930, it was only considered a planet for 76 years, before being "downgraded" to Dwarf Planet status. Most of us would be hard-pressed to name ANY of the other Dwarf Planets.

Pluto is smaller than the Earth's moon, but itself has five known moons.

Plutos' orbit is erratic, and sometimes it is closer to the Sun than Neptune.

In 2015, the New Horizons spacecraft flew by Pluto and took a few snapshots.

Mercury is the closest planet to the sun. It is the smallest of the planets, and orbits the sun (solar year) once every 88 days.

Even though it is further away, the planet Venus is actually hotter than Mercury.

Mercury was named after the Roman Messenger to the Gods.

The Mariner 10 spacecraft has flown by Mercury twice, in 1974 and 1975

Venus, the second planet from the sun, is very near the size of Earth. Unlike Earth, Venus has no moons. Also unlike Earth and most of the planets, Venus rotates in the opposite direction, so the sun rises in the West and sets in the East.

It takes Venus 255 days to orbit the sun once.

The first spacecraft to land on Venus was the Russian Venera 3, in 1966. The European Space agency orbited a craft around Venus between 2006 and 2015.

Venus is named for the Roman Goddess of Love and Beauty.

Ah, Mother Earth. The only planet not named after a deity. 4.5 billion years old, this is the only planet in the Solar System known to support life.

In popular thought over the centuries, the center of the universe was thought to be Earth. Then the center became the sun. Now we know that the entire Solar System isn't anywhere near the center. A humbling thought.

Some interesting water facts about Earth - the planet is actually 70% water, and only 3% of that water is fresh (unsalted). Of that 3%, more than 2/3 is currently frozen in ice sheets and glaciers. Think of that the next time you wash your car.

Mars, named for the Roman God of War, is often referred to as the "Red Planet", due to its appearance to the naked eye.

It's relative closeness to Earth makes it often visible in the night sky without a telescope, even though it is the second smallest planet in the Solar System.

There is evidence that there is water, or at least ice, on Mars which leads scientists to hope that there may also be some form of living organisms on the planet.

There have been around 50 missions to Mars (orbiters, landers, rovers) and about half of these have been failures. The next planned arrival is scheduled for early 2021.

Carl Sagan must have been a big fan of the Asteroid Belt - it contains "billions and billions" of pieces of debris, many the size of pebbles. Despite the numbers, it is theorized that if you were to stand on any single asteroid, you would be unable to see another one. This is one reason spacecraft have been able to move through the belt without damage.

The belt is located primarily out beyond the orbit of Mars, although occasional strays move out of the area. There have been several reports of "near miss" collisions with Earth. If you consider 45,000 miles to be "near"!

In both science and science fiction, it has been theorized that asteroid "mining" could become an important part of the future of space exploration.

Jupiter is the Big Boy of planets, and although it is a great distance from Earth, it's size allows it to be the fourth brightest object in the night sky, after the Sun, the Moon, and Venus.

The large red "eye" seen in most pictures of Jupiter, is a violent strom that has been raging for over 350 years. It is so large that three Earths could fit inside of this area alone.

It takes nearly 12 Earth years (11.8) for Jupiter to orbit the Sun once. This means that on average, Jupiter will make that long trip only six or seven times during your entire lifespan.

Jupiter has 79 known moons. The largest - Ganeymede - is bigger than the planet Mercury.

Several spacecraft from Earth have flown by Jupiter to explore it, and two have orbited the planet in order to study it more closely.

Jupiter is named, appropriately, after the king of the Roman Gods. (Greeks would refer to Zeus, Germanic tribes would call him Thor)

Saturn is probably the most recognizable planet, other than Earth. Why, because of the distinctive and massive rings, which are made up of ice and dust. The scale of the rings is impressive, they stretch more than 120,000 KM (75,000 miles) out from the planet, but are only about 20 m (65 feet) thick.

Saturn has around 80 moons or moon-like objects orbiting it as well.

There have been 4 spacecraft to visit Saturn, including Cassini, which orbited the planet nearly 200 times over a 13 year period, until it was intentionally crashed into the planet in 2017.

Saturn is named for the Roman God of Agriculture.

Uranus was the first planet to be discovered by telescope, in 1781. It was named for the Greek God of the Sky, Ouranos.

Like Saturn, it is a ringed planet, although the eleven inner and two outer rings are not as prominent.

Uranus has a retrograde (opposite direction) rotation from Earth, and one rotation takes place ever 17.25 hours.

Uranus has 27 known moons.

In 1986, the Voyager 2 spacecraft flew by Uranus, but that is the sole visit by any Earth object.

Neptune is the most distant planet from the Sun, it is 30 times further away than Earth. It was first observed from Earth in 1846.

Neptune as at least 14 moons, as well as a very thin set of rings, like Saturn and Uranus.

Because of its distance and orbital speed, Neptune has only made one complete circuit of the Sun since its discovery over 170 years ago.

The Voyager 2 flew by in 1989, and is the only terrestrial visitor to date.

We gratefully acknowledge noted celestial photographer Anthony Ayiomamitis for his permission to use the image that is our "outer space" background.