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.