GOES-R

Artists impression of GOES-R

Besides taking awesome pictures with telescopes and studying deep space, astronomers often work with geologists to study the structure of Earth and our weather patterns. One such endeavor is the Geostationary Operational Environmental Satellite (GOES) project, run by the US Environmental, Satellite, Data, and Information Service. Their job is to launch satellites that constantly study weather patterns on different part of the Earth so that the weather man can give us an "accurate" forecast each morning. The GOES satellites are in a geosynchronous orbit around earth. That means they orbit the Earth at the same speed at which the Earth rotates, allowing the satellite to appear stationary in space from a given spot on Earth. Currently there are 5 functional satellites (GOES 11-15), with the next generation (GOES-R, artists impression above) pending launch in 2015. Want to learn more about GOES, GOES-R and their mission pgoals? Have children that are interested in space and weather? Check out the GOES-R page for kids: scijinks.gov, or download the free game app: Satellite Insight.

Image credit: Lockheed Martin

Free Astronomy Apps

If you have an iphone or other smartphone, you've probably discovered that there are quite a few astronomy apps out there. Most of them cost a few bucks,  but there are some pretty cool free ones out there. Here's what I have downloaded to my iphone that you should check out for yourself:

Exoplanet Database: This is an awesome app if you're into exoplanets! It's a database with information about all the different exoplanets that have been discovered, and includes size, period, distance, and other useful information. You can read news about exoplanets, view where any exoplanet is located in the galaxy, make handy graphs of exoplanet properties, and even get links to scientific papers about the exoplanets. The coolest part about this app… it sends a text message to your phone every time a new exoplanet is discovered!

APOD Viewer Lite: An application that lets you view the astronomy picture of the day. It shows you the image, explanation, and lets you look back at previous images. Very nice app to quickly view today's APOD.

NASA: Basically this is NASA.gov in app form. You can find news,  launch schedules, pictures, videos, telescope info, and anything astronomy you can imagine. Excellent educational app.

ArXiv: This app allows you to search the astrophysics arXiv for scientific papers, and download the pdf to your iphone (using a pdf reader app). This is more for the serious astrophysicists, but anyone can peruse through the papers and maybe you'll find something interesting.

Galaxy Collider Lite: A cute app that shows you what would happen if two galaxies collided. I'm not sure how scientifically accurate the simulations are, but it's cool to watch the galaxies interact regardless. You can set the number of stars, mass of the galaxies, speed of collision, etc. and observe how that changes things

If you've discovered any other cool free apps, post them in the comments section below! Also feel free to leave your opinion about different non-free apps as well!

Near Earth Asteroid 2005 YU55

Most asteroids sit peacefully in the asteroid belt between Mars and Jupiter. Occasionally, some get kicked out due to tidal or gravitational forces between space objects, giving them their own orbit around the sun. Some of the stray asteroids pass fairly close to earth, and when they do we call them near earth asteroids. 

2005 YU55 imaged with the Arecibo radio  telescope

You may have heard talk on the news of a near earth asteroid called 2005 YU55 (pictured above). There's been a bit of hype about this object lately, but its just another member of the group of 8500+ near Earth objects that pass safely by Earth all the time. Now, "near" in the case of 2005 YU55 means that it will be 202,000 miles away from earth at its closest approach on November 8th, 2011. That's just a little bit closer than the moon is to Earth. So don't be alarmed by the news stories entitled "huge asteroid headed for close encounter with Earth"; there's nothing to worry about! NASA has assigned it a risk of 0 on their danger scale (ie. it's no big deal!)

Image credit:  NASA/JPL-Caltech

Acceleration Due To Gravity

We experience gravity everyday. It's the force that keeps our feet on the ground, makes apples fall from trees, and is occasionally cursed when you drop and break something. Newton may have "discovered" the theory of gravity, but it was Galileo (back in the 16th century) who claimed that all objects, regardless of their weight, shape, and size, fall at the same rate. In other words, the acceleration due to gravity is the same for all objects! Gravitational acceleration is governed by the size of the object causing the gravity. So here on Earth, gravitational acceleration (g) is 9.8m/s. So if I drop a hammer and a feather from the same height, they should reach the ground at the same time… right? Well scientifically, yes, but that often doesn't happen on Earth. Why? Well that's because we have a thick atmosphere and wind which causes air resistance. Lighter objects are more easily affected by wind, where as heavy objects are much less affected. So If do the hammer-feather experiment on Earth, the feather gets caught up in the wind and falls much slower that the hammer. But what happens in a place like the moon where there is  less gravity (1.8m/s) but no atmosphere and thus no air resistance. Do the hammer and the feather fall at the same rate? Let's find out…..

Video Credit:Apollo 15 Crew, NASA

Spooky Space

Below is a collection of Halloween themed space objects… Enjoy!

The Witches Nebula: Shaped strangely like the head of a witch, this reflection nebula shines brightly in blue because it's reflecting starlight from the large B star Rigel in the constellation Orion.

 

Ghost of the Cepheus Flare: This collection of dust in space is starting to trigger young star formation

Little Ghost Nebula: This strange looking object is a planetary nebula, the result of a star like our sun reaching the end of its life and shedding its outer layers of material.

 

Ghost Head nebula: This star forming region is located in the Large Magellanic Cloud, a small satellite galaxy of the Milky Way.

The Northern Lights

If you live within 20 degrees latitude of Earth's magnetic north pole, seeing the northern lights (or aurora) is a common occurrence. For those of us that live in Rochester, NY, a glimpse of the aurora was a treat this past Monday night. So what are the northern lights and how do they occur? Well, the aurora on Monday was the result of a coronal mass ejection (CME) hitting Earth's magnetic field. A CME is a large outburst of charged particles that is suddenly released from the sun. A quick search for CME on YouTube will get you lots of nice videos. When the CME hit Earth's magnetic field, the particles were directed to the north and south magnetic poles, essentially "grounding" this stream of charged particles. The colorful lights in the sky occur due to an interaction of the electrons and energy in the CME and the oxygen and nitrogen in the atmosphere.

 Chemical elements can be in one of many states. In the ground state, they have the required number of electrons orbiting their nucleus and are stable and happy. Elements can also be in an excited state where the electrons are all there, but they sit in what chemists call higher energy levels. Basically the atom gained some energy and the electrons are holding onto that energy, making the atom slightly less stable. Another thing that can happen is that an atom gains so much extra energy that an electron gets "kicked out" and lost completely from the atom. This is called ionization. When a CME full of energy and electrons hits Earth, it can bump atoms into higher energy states, ionize atoms, and also give back electrons to ionized atoms making them more stable. When an atom goes from being excited back to the ground state, or when it regains an electron, it releases excess energy in the form of light. Different elements release different amounts of energy due to their physical properties, and therefore emit different colors of light. Oxygen often emits green light, while nitrogen emits blue or red light, depending on whether it's regaining an electron or falling to the ground state. This emission of light by the elements in our atmosphere due to interactions with particles in the CME is what causes the northern lights! Below are some images taken by members of the Rochester Academy of Sciences Astronomy Chapter of the aurora visible from upstate NY.

Images courtesy of: Dave Bradley (left) and Larry Arbeiter (right)

 

Images courtesy of: Kevin Zwiebel (top) and Nick Lamendola (bottom)

The Kelvin Temperature Scale

 

Here in the United States, we measure temperature in Fahrenheit. Most of the rest of the world uses the metric system and measures temperature in Celsius. In the mid 1800's, scientists came up with a new system  to measure temperature called the Kelvin scale. The Kelvin scale ranges from absolute zero (the point at which all movement inside atoms ceases) to infinity. This type of "absolute" temperature scale is more scientifically accurate than Fahrenheit or Celsius as "0" is the coldest an object could ever theoretically get. This scale is easier to understand conceptually, and works nicely when doing calculations. We can relate the three scales by noting that the freezing point of water (0 C, 32 F) is equivalent to ~273 Kelvin (K), and "room temperature" is about 300K. The Kelvin scale is handy for astronomy as it helps put the temperature of astronomical objects into perspective. The cosmic microwave background (which is what "fills" what we perceive as outer space) is about 2.7K. The surface of the sun is ~6000K, and the sun's corona is about 2,000,000K! When put into perspective, humans are only accustomed to living in a temperature range that spans ~40K, whereas the universe has objects whose temperatures range from practically zero to billions of Kelvin!