Fourth Moon Discovered Around Pluto

NASA announced the discovery of a fourth moon around Pluto last week! Astronomers were using the Hubble Space Telescope to look for rings around the dwarf planet when they discovered the new moon. It's currently designated P4 until they come up with a better name for it. The Hubble image above shows Pluto and its four moons. The big black bar down the center is used to block most of the light Pluto reflects so faint objects around it, like the moons, can be seen. P4 is only 8-21 miles wide, whereas Charon is 648 miles wide and Nix and Hydra are more like 20-70 miles wide. Pluto is a member of the Kuiper belt, along with 70,000+ other objects, so it's not surprising that Pluto has another moon that went undetected for years. It's difficult to see such small objects in space, even with Hubble! NASA's new horizon mission is currently on its way to Pluto to study the planet and its moons. It will be another ~5 years before New Horizons makes it there, but once it has arrived it will no doubt send back unprecedented information about Pluto and other outer solar system objects

Image Credit: NASA, ESA, and M. Showalter (SETI institute)

Doppler Shift

Astronomers use a phenomenon called the Doppler shift to measure how fast objects are moving towards or away from us in outer space. But how does the Doppler shift work? Here's the common example. You pull over to the side of the road because you hear an approaching ambulance. As the ambulance gets closer, the siren sounds like it's being emitted at a higher pitch. This happens because the sound waves are compressed in the air as the ambulance approaches, making their wavelength shorter and pitch higher. The opposite occurs after the ambulance passes; the sound waves stretch and increase in wavelength and the siren sounds lower pitched. 

Light waves experience this same phenomenon of squeezing and stretching as an object moves. Relative to the Earth, objects that are moving away from us have their light waves stretched to longer wavelengths, making the object appear more red. If an object is moving towards earth, it's light waves are compressed to smaller wavelengths making the object appear more blue. We can measure how Doppler shifted an object is by observing spectral lines emitted or absorbed by different elements in the moving object. In the image above, some absorption lines were red shifted, meaning this object is moving away from us.  The larger this change in wavelength (called "red shift" or "blue shift"), the faster the object is moving. Some objects are moving so or are so far away that their lines are shifted out of the visible spectrum and into other portions of the spectrum not normally seen! Astronomers have viewed many ancient galaxies whose light appears today in the radio, but was originally emitted in the visible spectrum.

Image Credit: Wikipedia commons

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