Monday, April 30, 2012
There are two types of electric charges, negative and positive. Positive charges repel each other. As do negative. Negative and positive charges attract, however. The particles that make up all matter, atoms, contain these charges. Atoms are composed, however, of even smaller particles. There are protons, positively charged, electrons, negatively charged, and neutrons, which do not have any charge. Protons and neutrons are in the center of the nucleus of an atom. Electrons move around these in various orbits. If the atom contains the same amount of electrons and protons, they cancel each other out and the atom is neutral. If not, it has an electric charge. An atom with a charge is called an ion. A negative ion has a negative charge, and a positive ion has a positive charge.
Electrons can be transferred between two objects. If two objects rub together, one looses electrons and the other gains. Now they both have a charge. Some objects are more likely to lose or gain electrons.
Friday, April 27, 2012
To make the red planet green, we would need an atmosphere that could support life. There are large amounts of carbon dioxide in Mars's polar ice caps. If we could raise the temperature of the planet, it would start to melt. Hey, we've managed to do it here - why not on Mars, too? If the temperature of Mars went up, water in the planet would start to melt. We would need this water, since the price of shipping would be huge if we wanted it from Earth.
Another problem is the amount of nitrogen in the atmosphere. Earth has 70%. Mars has 3%. Nitrogen is essential to life. We would have to bring nitrogen in. This could be done by taking rockets out to the asteroid belt and selecting certain ones with plenty of nitrogen, then driving them back. This, however, turns an already incredibly ambitious project into a near impossibility. In the best case scenario, if everything went well, after this was done, it would take a hundred years to complete. Growing plants on Mars, which would be necessary, is made difficult by radiation.
If everything went smoothly and we could grow plants, the oxygen levels might be enough to just barely survive on Mars in a thousand years. Then there would have to be volunteers who would move to Mars. But, if we ever actually could terraform Mars, we would probably find a way to clean up Earth, which would be easier anyhow.
Nowadays, we have more advanced tools. These instruments measure the waves of radiation given off by objects in space. There is a spectrum to measure how much various objects give off. At the right end of the spectrum, we have gamma rays, X-rays, and other rays. At the other end are radio and infrared rays. We can see only a very tiny amount of these rays, the ultraviolet rays, which make up the rainbow.
Radio telescopes pick up radio waves. The telescopes pick up waves, then amplify them and send them to a computer, which processes the information. By studying these waves, scientists can learn about far away galaxies and planets that are far, far away.
Infrared telescopes pick up on the waves that we feel as heat. We can't see the signals, but can sense them instantly. These allow astronomers to guess at the temperature of a certain object. Some snake have eyes that locate prey by detecting sources of heat.
Ultraviolet telescopes need to be placed outside of Earth's atmosphere in order to work, since our atmosphere blocks out most ultraviolet rays. They pick up on the ultraviolet rays. New stars and many of the most active objects in the universe emit these rays.
We have many inventions with which to explore the solar system. And, in time, who knows? Maybe we will be able to look for ourselves.
Wednesday, April 25, 2012
The short answer is we don't know. But since this post should probably be a bit longer, I'll ask another question. Is there a good chance of intelligent extraterrestrial life in the universe?
We have not yet made contact with extraterrestrials. SETI, the Search for Extra Terrestrial Intelligence, has not found anything. We have sent out satellites with greetings in various languages, in hopes that, if the satellite finds anything, they might be able to decode what we're saying. However, for life to exist on a planet, it has to have very certain conditions for life. We haven't seen any planets that could sustain life aside from our own. On top of that, where would the life have come from? Life can't create itself.
If life did exist out there, there's little chance we'll ever see it. If we traveled at one tenth the speed of light, a trip to our nearest star would take 43 years. And enormous amounts of energy is necessary for such travel. Moving at the speeds this type of travel require is dangerous. Hitting a single speck of dust could do serious damage to the outside of a space ship.
Some people like to think that the government knows about the existance of aliens and is covering it up. Why would they do that and continue to spend millions of dollars on the search for them?
So it's unlikely we'll find intelligent life any time soon. But still, who knows?
Tuesday, April 17, 2012
Most people know what makes up the solar system. The planets, which revolve around the sun. But what's outside the solar system?
Well, to answer that question, where does the solar system end? Well, past Pluto, one of our dwarf planets, we have a thin haze of dust. This dust is held in the sun's gravitational pull, so it is part of our solar system. This dust may stretch out halfway to the nearest star, approximately 4.2 light years away. There are many, many different types of stars in the Milky way. At our very center, there is thought to be a black hole, hidden by the clouds of the constellation Sagittarius.
The universe is mostly empty space. But since the universe is so big, there's still plenty to see. One of our neighbors is the Large Megellanic Cloud. It is made of of stars, gas, and dust. There are star clusters inside it, and nebula, which are dust and gas, from which stars are sometimes born. There are neighboring galaxies, such as the Andromeda Galaxy. Sometimes, galaxies are pulled into orbit around another. They collide and form new galaxies. It is thought that one day, our galaxy with collide with Andromeda.
Friday, April 13, 2012
The idea of an elevator to space has been around since the 1960's. It comes from an idea for a satellite attached to Earth by a strong cable. Vehicles could travel to and from the satellite along the cable. Unfortunately, there are problems with this idea.
The cable could not be pulled behind a space vehicle as it took off, as it would slow it down. So it would have to be lowered from space. If a heavy cable is lowered from a satellite, the satellite's center of gravity changes. The satellite must go higher in order to adjust. A cable lowered in this fashion would have to be very long. A good design for this estimates the cable will be about 90,000 km long. This is long enough to circle the Earth. Twice.
The cable would also have to be strong. Steel wouldn't work. Not even diamond fibres. However, carbon nanotubes would work. A cable made of these would be light and thirty times stronger than steel. This cable would also be incredibly thin. The original design was for it to be 100 times thinner than a piece of paper. The entire cable could weigh 20,000 kg. The cable would likely be anchored offshore.
There are still problems. The cable could easily be damaged. And we actually don't know how to make a cable like the one required. The longest rope we've made out of nanotubes is only a few centimeters long. And the elevator can't exactly be tested. We can't only go part of the way up, then a little further. The cost of such a venture would be more than ten billion dollars. If we can work past these problems, however, we might soon be taking elevators to space.
Tuesday, April 10, 2012
Rockets are how mankind has always traveled in space. However, they are also expensive. A rocket's energy equivalent is around 20% of that of the nuclear bomb that was dropped on Hiroshima. The rocket that sent the astronauts to the moon cost $500 million dollars to launch. NASA has determined that the space shuttle needs to be retired and is working on other ways to take man into space.
So how will we get into space in the future?
One possible way is by giving the shuttles a little boost. For example, flying them up to a certain height where they can fire off their rockets and take off into space. The problem with this idea is that, to do so, the shuttle would have to be light. And, with the fuel required to get into space, the shuttles are not light.
In Jules Verne's book, From the Earth to the Moon, the space vehicle is fired from a gun barrel three football fields long. Canadian scientist Gerald Bull tested this theory and shot a 16 inch projectile into space. It is possible that, in his later career as a weapons designer, he was working on creating a much larger version of this that could shoot objects into orbit. He was thought to be building this weapon for Saddam Hussein's Iraqi government, however, and was assassinated.
With the technologies being developed, who knows where we might go next?
Friday, April 6, 2012
Have you ever wondered why Easter's date changes?
It's called a "movable feast". A movable feast is a "holy day" which is not fixed according to the calendar but moves in response to the date of Easter. Such days include Good Friday, which is set two days before Easter.
Why does Easter move? The First Council of Nicaea, which was a council of bishops in 325 AD who were attempting to sort out issues with dates and such in Christianity, declared it to be so. The Christians had generally just asked their Jewish neighbors which days it was, since it was at the same time as Passover, one of their own festivals. However, some Christians felt that the Jewish calendar was unorganized and inaccurate.
The council decided to create their own, independent calculations to determine the date of Easter. The holiday was declared to be the first Sunday after the full moon following the Northern Hemisphere's vernal equinox, the beginning of Spring. Ecclesiastically, the vernal equinox is on March 21, although it actually occurs on March 20 most years. The date of Easter, therefore, varies between March 22 and April 25.
Happy Easter, everybody!!!!!!
Wednesday, April 4, 2012
Galileo discovered Saturn's rings in 1610, using his newly invented telescope. His telescope, however, wasn't clear enough for him to tell they were rings. He thought they were large moons, almost half the size of Saturn. However, when he observed Saturn later, the moons had disappeared. Later, an astronomer discovered that the "moons" were actually a flat disk, which had been turned edge on to Earth when Galileo observed it. Saturn's rings turn edge-on to Earth every fourteen years. After that, another astronomer discovered that the flat disk was actually rings around the planet.
The rings of Saturn start about 6,000 kilometers from the planet and extend 480,000 kilometers. They are wide, but very thin, about a kilometer thick on average. They seem to be made up mostly of small particles of ice and rock. There are seven rings altogether.
Other planets also have rings. A spacecraft, sent to Jupiter, flew right through them with no one noticing anything at the time. The rings are as wide as Saturn's, but darker. Neptune and Uranus also have thin rings.
Eventually, the rings of Saturn will dim. Micrometeorites will smash the ice crystals in the rings. Left will be fragments of black rock and metal and dirty ice. This process will wear away at the rings. The rings will gradually grow darker and thinner until there is nothing left. Enjoy them while you can.