Venturing Among the Giants of the Solar System

Welcome back to What's Up?

Last month we started a tour of the solar system with the inner planets Mercury, Venus, Earth, and Mars. Let's continue that tour with the solar system's outer planets.

Before we continue our tour, the asteroid belt, which lies between the inner and outer solar system, must be acknowledged.

The asteroid belt is essentially a large zone filled with millions upon millions of space rocks, called asteroids. This belt is an interesting place and will possibly be the site of a future "gold rush." In one small asteroid (a kilometre or two across) there could be tens of trillions of dollars worth of precious metals and iron.

Unlike in movies and video games, navigating through the asteroid belt is fairly easy. The belt is so large that the asteroids are spaced many kilometres apart and are easy to avoid.

Now that we've safely navigated the asteroid belt we encounter Jupiter, the king of the planets. This huge planet is eleven Earths wide and has a mass 320 times that of Earth (see size comparison in the below image).

Jupiter has cyclones in its atmosphere that are so energetic they make Earth's hurricanes seem like a gentle breeze. One of those cyclones has been raging across the planet for 400 years and is three times the size of the Earth!

Jupiter also has four large moons, each of which are larger than our moon. These moons are Io, Europa, Ganymede, and Callisto.

The largest of these is Ganymede, so large that it is even larger than the planet Mercury. It may contain an ocean under its thick icy crust.

Europa is another moon with an ocean under its icy crust. This moon will hopefully be visited by a submarine mission to explore its oceans in a few decades. Maybe a Europan fish or eel will swim by the camera. Even a simple microbe would be one of the biggest scientific discoveries ever.

The next planet outwards from the Sun is the planet Saturn (image at left). Saturn features a great set of rings which encircle the planet. These rings are made of tiny chunks of ice and rock.

One of Saturn's moons is larger than Mercury and even has an atmosphere ten times thicker than Earth's. Instead of water raining from the skies, it rains liquid methane at -180°C.

Before we have to put on a tuque, let's move on to the planet Uranus (image below Saturn).

This planet lives up to its gassy giant status with significant amounts of methane in its atmosphere. Although it is commonly made fun of because of its name, it is a very interesting pale blue world which needs to be explored up close.

Most of Uranus' moons are named after characters from Shakespeare's writings. One of the moons, Miranda, is extremely bizarre. Miranda appears to be a heap of jumbled and mismatched pieces.

Moving on to Neptune, the last planet in the solar system (Pluto is now considered a dwarf planet), there is hardly any sunlight. This frigid world is almost completely composed of gas like the other giant planets Jupiter, Saturn, and Uranus.

Neptune (at left) may be the coldest planet, but it has the fastest wind-speeds and even had a storm the size of the Earth when the Voyager spacecraft flew by.

Neptune's largest moon, Triton, has cryogenic volcanoes. These volcanoes spew liquid water instead of lava.

Much is left to be learned about all of the planets, and in particular the outer solar system. Hopefully someday missions will be sent to learn about these interesting and exotic worlds.

Until then, let's see what's up in the sky this month.

The new Moon will be on April 14, while the full Moon will be on April 28.

Early in the month, shortly after sunset, Venus and Mercury will be next to each other low on the western horizon. Venus will be much brighter than Mercury.

Mars will be a bright orange-red high in the south while Saturn will be a mellow yellow in the south-east.

This month is Global Astronomy Month, an initiative to spread the wonders of the night sky. Astronomy Day will be on April 24 this month. Keep on the lookout for possible astronomy related events.

The monthly meeting of the Athena Community Astronomy Club will be on the last Sunday of the month, April 25, as usual. The meeting starts at 7pm and ends at 9pm. Guests are always welcome.

Until next month, just look up!

Hey Kids...

Astronomers recently discovered that the estimated number of galaxies in the universe is wrong. A galaxy is a blob of billions of stars. It turns out the estimated number of galaxies was ten times less than the actual number. They discovered the extra galaxies by tuning their cameras to look at a different colour of light that hadn't been looked at before. Our eyes have similar problems. We can only see visible light, which is a tiny fraction of all the colours of light. Infrared light can pass through clothing so maybe it's a good thing that we can only see visible light!

What's Up? The Outer Solar System's Frigid, Yet Fierce Weather

Welcome back to What's Up?

Now that Summer has come to an end, the Athena Community Astronomy Club has wrapped up their weekly boardwalk viewings. Thanks to club members who made this possible and to everyone who dropped by to take a peek through one of the telescopes.

Although the weather wasn't great throughout the Summer, it doesn't even compare to the weather on other planets. Let's continue last month's tour of the weather on other planets in our solar system.

Last month we looked at the inner solar system, the rocky planets, and this month we'll continue to move outwards into the outer solar system.

Jupiter, the fifth planet from the Sun, is the largest planet in the solar system. If you were to take all of the planets, comets, and asteroids, and put them together, they would easily fit within Jupiter.

Jupiter's massive size also comes with intense weather. A normal wind-speed that you could expect "on" Jupiter (it is made of gas and has no solid surface) is about 360 km/h (225 mph). The fastest wind speed ever recorded on Jupiter was an astounding 620 km/h (390 mph). Combined with Jupiter's -150°C (-238°F) "surface" temperature, there would be one nasty windchill!

Category five hurricanes are dwarfed by all of Jupiter's storms. It's biggest storm is currently twice the volume of the Earth and has been going non-stop for at least 400 years! This storm has sustained wind-speeds of 430 km/h (270 mph)! Another thing to watch out for: lightning, and lots of it. From Jupiter's night side, space probes have watched some of the largest lightning storms ever seen.

Moving on to Saturn, the sixth planet from the Sun, and the second largest, is a planet with some of the fastest winds in the solar system. In many regions there are sustained winds of up to 1760 km/h (1100 mph)! Combined with it being a gas giant like Jupiter (no solid surface), intense lightning, and a frigid average temperature of -184°C (-300°F), Saturn is not a good place to plan this year's vacation!

The next planet from the Sun, Uranus, another gas giant, is the third largest planet and doesn't have much better weather than Saturn. Even though it is the second coldest planet, at -210°C (-350°F), it still boasts impressive wind-speeds of up to 825 km/h (515 mph).

Last but not least, Neptune, the eighth and final planet from the Sun, is also the coldest, with an average temperature of -220°C (-370°F)! For some reason that has eluded scientists so far, the coldest planet in the solar system also has the fastest winds. These winds blow around the planet at a break-neck speed of up to 2100km/h (1300 mph), almost 600 meters (1800 feet) per second!

Pluto, now a dwarf planet, is so small it barely holds on to an "atmosphere" that is 700,000 times thinner than the Earth's atmosphere. It is so cold here, -235°C (-390°F), that its atmosphere (mainly Nitrogen), literally freezes out of the sky and snows to the ground!

Before Pluto reminds us of our upcoming winter, let's check out what's up.

The Moon will be full October 4 and will diminish to a new Moon by October 18.

Jupiter will be in the South in the early evening sky, it will be the brightest "star-like" object in the sky.

In the morning sky, half an hour or so before sunrise, will be Venus, Saturn, and Mercury. Venus will be by far the brightest object in the sky (other than the Moon and the Sun). Saturn and Mercury will be fairly dim and hard to pick out, Mercury will be only staying around during early October. All three can be seen in the East.

The Athena Community Astronomy Club's monthly meeting will be held on the last Sunday of the month, October 25, at the Wilmot Community Centre in Summerside. It starts at 7pm and runs to 9pm. All guests are welcome.

The astronomy club's website, although a work in progress, is up and running. Check it out at:http://acac.wetpaint.com.

Until next month, just look up!

Hey Kids...

Last month, NASA scientists announced the discovery of water on the Moon. The Moon rocks brought back in the 1960's contained no water but now the scientists have found water all over the Moon. It's not much, but it will be enough to allow future colonies on the Moon to mine water from the soil. People living on the Moon may seem pretty far off, but NASA is planning on returning people to the Moon by 2020. Living on the Moon may not be science fiction for much longer!