What's Next For NASA?

The shuttle program officially ended this morning around 6am EDT as Atlantis safely landed back on Earth at Kennedy Space Center. Many people seem to think that the end of the shuttle missions means the end of NASA. This is by no means true! Just because we aren't sending astronauts into space doesn't mean our space program is shutting down! NASA is hard at work developing new technology for future manned space missions, and is planning many robotic missions for the near future. Hubble, Spitzer, and Chandra are still operational and providing astronomers with gorgeous views of space objects. As long as funding continues, JWST will be launched in the upcoming years giving astronomers huge amounts of data to work with. So much is left to be learned about our own solar system and NASA is working on many orbiters, landers, and rovers will be launched to planets and moons in our solar system.

It's sad to see the shuttle program go, but we can still do great science without sending man into space. In fact it's often easier and more beneficial to send a satellite or robot rather than a person into outer space. To learn more about what's next for NASA, check out this excellent article: http://www.nasa.gov/about/whats_next.html

Comet, Meteor, or Asteroid?

Leonid Meteor Shower

It's a bird! It's a Plane! It's a comet! No wait, a meteor! Or maybe an Asteroid? I know I'm guilty of using these three word synonymously, but each one has a distinct astronomical definition.

Meteoroids are small bodies that range from the size of a grain of sand to the size of a car. Meteoroids that enter Earth's atmosphere are called meteors and when they fall in groups they are called meteor showers. Most meteors break apart completely as they fall through Earth's atmosphere, but those that survive and impact the ground are called meteorites.

Comets are large bodies in the solar system made mostly of ice, dust and small rocks. They range in size from 100m (~300ft) to 100km (~62 miles) and originate from the outer edges of our solar system. Comets are different from other astronomical bodies because they have a visible tail resulting from the solar wind stripping particles off of the comet. About 4,200 different comets have documented in our solar system, and pass by Earth periodically. Comets continue to orbit the sun until they either break apart from solar radiation, crash into the sun, or get ejected from the solar system.

Asteroids are a broad term for pretty much any body in the solar system that's not a planet, moon, meteoroid, or comet. They can be any size or shape and exist in two main areas: the asteroid belt between Mars and Jupiter and the Kuiper belt beyond the orbit of Neptune. Some asteroids orbit closer the to the planets. Astronomers are working on finding and classifying all such asteroids so we can watch for any that might be on a collision course towards Earth!

Image Credit:  Geek.com/gearlog

What is the Universe Expanding Into?

What is the universe expanding into? Well that's a good, yet slightly mislead question. Often when we learn about the expansion of the universe we are told to envision it as a balloon that’s being blown up. Dots on the balloon represent galaxies, and as the balloon is blown up, the space between galaxies increases, representing the expansion of the universe. This is a somewhat poor analogy, as it makes us think of the universe as an object that expands into a surround space (the air in the room). This is not true. Instead of thinking about the universe as an object that expands into another space, think about it as a sheet of rubber. The universe contains any imaginable space, and can be stretched like a rubber band. Don't think of universe expansion as galaxies hurtling outwards pushing the edges of the universe farther and farther out. Imagine instead that the galaxies are stationary, and that the space between them is stretching, causing the universe to expand.

This helps answer the question: what is the universe expanding into? Well, since the universe is all space, it's not expanding into anything. Rather, the entire universe is stretching and becoming larger.

It's ok if your still a bit confused…. So are astronomers! There are various theories about the structure of the universe and how it moves. Until we can come up with some observational evidence proving one of these theories correct, we will all sit here puzzled about the "edge of the universe" and what might be "beyond" it.

Rocket Fuel

This post was prompted by my recent endeavor to  create a safe, yet effective way for high school age kids to launch home made bottle rockets….

Ever wonder what fuels the space shuttles? The solid rocket boosters contain the propellant that initially gets the rocket off the ground. The main propellant is ammonium perchlorate, a white granular chemical that, believe it or not, is not terribly toxic. The rest of the fuel consists of aluminum, iron oxide, epoxy, and  some sort of polymer (a molecule that helps hold all the fuel parts together). The solid rocket boosters sit underneath the external tank are ignited electronically, often from the ground. These monstrous tanks of fuel weigh 1.3 million pounds when full, and produce 2.8 million pounds of force(that's a lot of force!)

So if your kids decide they want to do a rocket launch experiment for their science fair project, here's my advice: buy a rocket launch kit with a solid fuel component. I've spent a good deal of time trying to get fuel like Alka-Seltzer and water, vinegar and baking soda, and compressed air to work as good propellants. And despite the numerous you-tube videos showing nice rockets, liquid and air propellant just doesn't work. Trust me, it's safer for them to get an Estes electronic rocket launcher. Happy rocket launching!

Final Shuttle Launch

 

At 11:28 am eastern time, the final space shuttle, Atlantis, took of from Kennedy Space center in Florida. The image above was taken just after liftoff. NASA broadcasted the launch live on their website, and you could see thousands of people watching. I've had the pleasure of watching a shuttle or two launch from the beaches of the space coast, and let me tell you it's a spectacular sight. Sadly, the space shuttle program ended today, mostly due to lack of funding from the government.

The first space shuttle, Columbia, launched in April of 1981, and a total of 134 space shuttle missions have occurred since then. The purpose of many shuttle missions was to construct the international space station (ISS), bring the ISS supplies, transport people to and from the ISS, and service telescopes and other equipment in space. Other countries will continue to have manned shuttle missions to the ISS and elsewhere. There's even a chance that private businesses will fund or conduct shuttle missions of their own here in the US! But unless something tragic happens at the ISS, NASA's shuttle program will stay dormant. Hopefully funding will be renewed in the near future and we will again be able to send astronauts into space!

Image credit: NASA TV

"Proof" That Dark Matter Exists

Previously, we discussed the fact that 96% of the universe is made up of things we don't understand. About 22% of this we call dark matter. We think dark matter exists because we see regular objects, like  stars and galaxies, interacting  gravitationally with something that we can't see. The best and easiest to understand example of this comes from galactic rotation curves. Galactic rotation curves (shown below) are a graph showing how fast different parts of a galaxy spin. Here's what we expect. Think of a galaxy as a large funnel. You have a black hole at the center attracting all matter, and the rest of the galaxy extends outward in a circular fashion. If you were to take a marble and roll it along the inside of the funnel, how would the speed of the marble's rotation change? Well, you should see that the marble rolls slowly when its close to the edge, and much faster as it approaches the inside of the funnel until it falls through the central hole. We expect to see the same behavior in stars orbiting around the black hole in the center of galaxies. Stars close to the galactic center should orbit quickly, and the speed should decrease as you move away from the center. Below is a simple galactic rotation curve showing what scientists predict, and what we observe for almost all galaxies.

As you can see, stars in a galaxy all orbit the center at about the same speed! This means that your marble is rolling around the inside of the funnel at the same speed regardless of whether its at the edge or about to fall through the center! Physics states that the velocity (speed) of an object due to gravity is proportional to its mass. The only easy way to explain this is that there is lots of matter that we can't see towards the outer edges of galaxies, ergo Dark Matter! This would allow the stars at the edge of the galaxy to orbit at the same rate as the ones near the center.

Of course there is always the possibility that our science or math is incorrect, and the theory of gravity needs to be modified. Some scientists are working on that idea, but dark matter is still the winning hypothesis.

The Universe Is Made Of.... Umm.... Well...

Often when I'm teaching an astronomy class to the general public, I begin with a “what is the universe made of?” slide. I show pretty pictures of stars, galaxies, planets, etc. and discuss all the different objects astronomers are studying in outer space. But when I do this, I'm technically lying to everyone. These observable objects actually make up only 4% of the entire universe! To be honest, astronomers have almost no idea what makes up the other 96% of our universe! The current most popular idea is that the universe is also made of 22% dark matter and 74% dark energy. Dark matter is just “stuff” distributed throughout space that interacts gravitationally with other things, but doesn't emit or interact with light. Ergo “dark” matter. Dark energy is this mysterious entity that is causing the expansion of our universe. The universe is expanding at an increasing rate, and therefore something must be “pushing” the universe, giving it energy to increase its rate of expansion. Nobody really understands what this energy is or where it comes from, but we call it “dark” energy because it must be there, we just can't see it. A bit unnerving that the people that are supposed to know everything about outer space really have no clue about 96% of it huh? So how do we “know” that this crazy dark matter and dark energy exists? Well that's a topic for upcoming ADYK posts....

image credit: Hubble/NASA