The downside of physics!

Destroying aging weather satellite

I was reading an issue of SkyNews-The Canadian Magazine of Astronomy & Stargazing, when a particular article caught my eye. It was about the deliberate explosive destruction of a Chinese satellite, which has thrown thousands of pieces of debris in a 'potentially destructive orbit' around the Earth.

It was January 11, 2007 when China fired a missile to destroy an old weather satellite, called Fengyun-1C. This was deemed an anti satellite missile test, the first by any country since the mid-1980s. Although Chinese government said that it was not intended as a hostile act. The blast from the 750 kilogram satellite created a cloud of debris that began spreading out 865 kilometers above the Earth. According to NASA's Johnson Space Center over 2,200 pieces of debris larger than five centimeters have been tracked so far.

The exact words by Dale Armstrong were: "It's an environmental disaster. That's the only way to describe it." The debris is now travelling in the same low Earth orbit zone as the International Space Station and the Hubble Space Telescope. This zone is already becoming crowded with dead satellites and other miscellaneous pieces of junk. When moving at orbital speeds of eight kilometers per second, even something as tiny as a 0.2 millimetre chip of paint can seriously damage an active satellite.

Their size makes it impossible to predict potential collisions with active satellites. Alan Cacchione of the Canadian Department of Foreign Affairs and International Trade stated: "We had discussions with China to seek assurance that it will not undertake any further tests of this nature."

When I read this article I was quite shocked by China's fashion of destroying the satellite. My immediate reaction was one of environmental concern. With all the debris around our Earth isn't it possible that something could come out of orbit and strike Earth? Not only that but isn't this harmful to our Environment? I hope that this won't occur again and it's rather disappointing that it was an anti satellite missile test.

Punishment of Vainity

I've always had a particular liking of the constellation Cassiopeia, mainly because it was the first constellation after the two Ursas that I could recognize in the night sky.

Cassiopeia was the wife of Cepheus, the Ethiopian King, and the mother of Andromeda. The queen was beautiful, yet had great vanity. She made the mistake of considering herself more beautiful than the Nereids or even Juno herself. The goddesses were quite insulted and complained to Neptune, god of the sea. He sent a sea monster to terrorize the people. As an order, the king and queen were to sacrifice their daughter, Andromeda. Had it not been for Perseus who killed the monster, they would have sacrificed her. As a reward Perseus was given Andromeda's hand in marriage.

Neptune placed Cassiopeia in the heavens, and as a final humiliation (due to her vanity) he put her in a throne which revolves around Polaris, so half the time she sits upside-down.

Once you're in there's no turning back

This is an artist's interpretation of a Black Hole

A black hole is basically a hole in space in which the gravitational field is so powerful that nothing can escape after having gone past the event horizon. The name came from John Wheeler who said: "Matter tells space-time how to curve, and curved space-time tells matter how to move." These holes are so dark that even light in unable to escape, making the interior invisible.

Black holes can be detected if they draw outside matter into it's funnel. An example of this would be drawing in gas from an orbiting star. The gas swirls inward, heating up to very high temperatures and emitting large amounts of radiation.

Presently black holes are understood by Einstein's theory of general relativity developed in 1916.

If an object is in a gravitational field it goes through a slowing down of time, this is called gravitational time dilation. This happens when the object approaches the event horizon and right before it is drawn inwards. To an observer, the object falling into the black hole appears to slow down, approaching but never quite reaching the event horizon. From the viewpoint of the falling object, far away objects may appear either blue or red-shifted. Light is blue-shifted by the gravity of the black hole, and is red-shifted by the velocity of the falling object.

There are three types of Black Holes:

• Stellar Black Holes- they are the end state of evolution of massive stars
• Galactic Black Holes- they are millions of solar mass and an example is the Milky Way Galaxy
  
• Primordial Black Holes- are tiny and may have been formed in the universe shortly after the Big Bang, although there is no clear evidence.
  

Black holes are hard to understand, as it is impossible to go inside one and observe.

Stellar Classification

I asked my roommate if there was anything she wanted to know about astronomy and I'd find out and write a blog about it. Her question was "what types of stars are there?"

First of all I'll start by star classification and how this is done. Stars are classified by their spectra and their temperature. There are seven main types of stars O B A F G K M in order from hottest to coolest. M stars are common but dim and O an B stars are uncommon but bright. Our sun is a G2 star. The numbers behind the letter go from zero to nine, zero being the hottest. Brighter stars have a shorter lifetime, about 10 million years. Our sun has a lifetime of 10 billion years.

The Hertzsprung-Russell (HR) Diagram is a graph that plots star color (which is spectral type or surface temperature) versus its luminosity (absolute magnitude). In the diagram three different types of stars can be seen: main sequence stars, supergiants, and white dwarfs.

Main sequence stars: are fueled by nuclear fusion and as they get hotter they become brighter. These stars are in the most stable part of their existence; this stage generally lasts for about 5 billion years. Our sun is considered a main sequence star. About 90% of stars are in the band of main sequence stars.

Giants: are stars that are beginning to die. They become Blue Giants, Red Giants and Red Supergiants as well as many variations such a Brightgiant, Subgiant etc. The core of these stars contract as the outer layer expands creating an explosion.

White Dwarfs: are smaller stars about the size of our sun that eventually become dim white dwarfs. These shrinking stars have given off all of their nuclear fuels and will become cold, dark black dwarfs.

Something that really intrigues me and I find hard to imagine, is the temperature of stars. To imagine something that is 40 000 degrees Kelvin is just hard to believe! Before I learned about stars, I always assumed incorrectly that our Sun was the brightest star. A reason for this probably being it's apparent magnitude and it's close distance to Earth.

The Sun's Anger

I was searching on NASA's Astronomy Pictures of the Day and I found a really neat video clip from November 6, 2007 of a Solar flare.

Without warning the Sun releases huge flares of hot gas into the Solar System. They have the abilitity to affect power grids on Earth, satellites and astronauts. This particular image was captured by the TRACE satellite. The gas flowing in loops are what we were taught are called Coronal Loops. It is basically material being thrown off of the sun on the layer called the corona. The flare is a shower of electrons raining down from the corona onto the photosphere, heating the coronal gas to temperatures usually encountered only deep inside the sun (10 million degrees Celsius).

The image was taken in September 2005, it captured the X-ray waveband. The twisting and reconnecting of these loops initiate the flare. NASA's Swift satellite detected a similar flare from a star called II Pegasi. It is 135 light-years from Earth and was one hundred million times more energetic than the sun's typical solar flare. If it had of been from our sun, it would have created a mass extinction on Earth. Fortunately our Sun is stable and doesn't create flares to this power.

Fun with Astronomy!

I am laughing as I am writing this blog. I just discovered a kid's learning website called kidsastronomy.com. What I found most amusing were the many songs about Astronomy. A few examples of these songs are: 'Why Do The Stars Twinkle', 'A Shooting Star Is Not A Shooting Star', and 'What Does A Greenhouse Do', just to name a few.

Not only did they make me laugh, but they also served as an educational tool! The rest of the website included games, puzzles, quizzes and jokes. Yes I know this is intended for children, but I did enjoy it and found the information really useful. I am sure that this is a wonderful learning tool for curious minds.

As time went on I started searching for other fun websites on Astronomy. The rest of this blog is the product of my search.

A joke I found was: Two atoms bump into each other. One says 'I think I lost an electron!' The other asks, 'Are you sure?', to which the first replies, 'I'm positive.'
I hope you have fun with Astronomy too!


'Twas The Night Before Christmas, NASA-style

'Twas the night before Christmas, when all through the stars
Not a creature was stirring, not even on Mars.
The space boots were hung by the airlock with care,
In hopes that St. Nicholas soon would be there.
The robots were nestled all snug on their tires,
As visions of upgrades danced through their wires;
Mom put on her headset while I counted prime numbers,
We had settled our brains for a long winter's slumber,
When out on the dome there arose such a clatter,
I sprang from my sack to see what was the matter.
Away to the porthole I flew like a flash,
And tore open the air filter with a great clash.
The moons on the crest of a new volcano,
Gave an alien luster to objects below.
When what to my wondering eyes should appear,
But a small UFO, and eight rocket reindeer,
With a little old driver so lively and quick,
I knew in a moment it must be St. Nick.
More rapid than light, his rockets they came,
And he whistled, and shouted and called them by name:
"Now Saturn! now, Sputnik! now, Titan and Atlas!
On, Redstone! on, Delta! Apollo, Polaris!
To the top of the dome! to the top of the wall!
Now blast away! blast away! blast away all!"
As meteors blaze through the heavens up high,
When they meet with the atmosphere and burn in the sky,
So up to the dome-top the rockets they flew,
With a ship full of toys, and St. Nicholas, too.
And then in a twinkling, I felt on the ceiling
The heat of the thrusters and landing tiles peeling.
As I covered my head, and was turning around,
Through the airlock old Santa Claus came with a bound.
He was dressed all in plastics, from his feet to his head,
And his clothes were all covered in dust that was red;
A bundle of toys he had flung on his back,
And he looked like a scientist opening his pack.
His visor- how it twinkled! his filter how scary!
His gloves were from Earth, the logos quite merry!
His space boots, how costly! they played songs and glowed!
The frost on his suit was as cold as Pluto;
The stump of his air tube held tight in his teeth,
And oxygen swirled round his head like a wreath;
He had a broad face and a little round belly
That shook, when he laughed, like a bowlful of jelly.
He was chubby and plump, a right jolly old elf,
and I laughed when I saw him in spite of myself;
A wink of his eye and a nod of his head,
Soon gave me to know I had nothing to dread;
He spoke not a word, but went straight to his work,
And filled all the space boots; then turned with a jerk,
And spreading his fingers just like Dr. Spock,
He quietly exited out the airlock.
He sprang to his sleigh, to his team gave a whistle,
And away they all flew like a high flying missile.
But I heard him exclaim, ere he drove out of sight,
"Happy Christmas to all, and to all a good night."


Copyright: Gail Koske Phillips and Patrick Koske-McBride

Auroras- why the different colours?

Auroras are a display of incredible beauty and are more commonly known as the Northern Lights (Aurora Borealis) and the Southern Lights (Aurora Australis).
They have always fascinated mankind and some of our ancestors believed that the “lights in the sky” served as paths which the souls of the dead traveled towards the gods. Others thought that the dancing colours were omens of great events, both good and evil.
The auroras at the Earth’s magnetic poles occur when highly charged particles from the solar wind interact with elements in the earth’s atmosphere. The charged particles are drawn towards the magnetic poles following lines of magnetic force generated by the earth’s core.
What fascinated me was the colourful display from the auroras and I never understood why and how the colours appeared. As a matter of fact the colour of the aurora depends on which atom of oxygen or nitrogen is struck in the atmosphere and at what altitude.

• Green - oxygen, up to 150 miles in altitude
• Red - oxygen, above 150 miles in altitude
• Blue - nitrogen, up to 60 miles in altitude
• Purple/violet - nitrogen, above 60 miles in altitude

The dancing of the auroras occurs because of the shifting of the magnetic and electrical forces reacting with one another.
Although auroras occur around the Arctic and Antarctic there are times when they move further south, usually during times when there are many sunspots. Since sunspots follow an 11-year cycle and they have an impact on auroras the next opportunity for seeing them outside their normal range is 2011 and 2012.
Auroras not only occur on Earth but have been spotted on Saturn and Jupiter as well. This phenomena is something everyone should see, myself included.

Potentially Hazardous Asteroids

I’ve decided to write this blog about Potentially Hazardous Asteroids (PHAs). They are asteroids that come threateningly close to Earth, 0.05 AU or less into Earth’s orbit. According to Near Earth Object Program in order for an asteroid to be considered a PHA it also has to have an absolute magnitude (H) or 22.0 or less, as well as coming 0.05 AU or less close to the Earth. Currently there are 906 known PHAs and by monitoring their orbits we can make more accurate predictions on the threat of an impact on Earth.

The smaller the magnitude of a PHA the larger the diameter. Example: a 3.0 magnitude (H) asteroid has a diameter of 670 km - 1490 km, while a 30.0 magnitude has a diameter of 3m – 6m!

The next PHA coming close to Earth is Apophis asteroid number 99942. It will approach the Earth closely in 2029. From collected data in 2005 enough information was given that the asteroid will not impact the Earth, merely coming really close.

Potentially Hazardous Asteroids can be quite accurately tracked because of their predictable orbits, and in my opinion knowing where they are is important.

Alan Hildebrand

The discovery of the catastrophic Chicxulub Crater in the Yucatan Peninsula of Mexico was made by Alan Russell Hildebrand in 1990.

Hildebrand received his bachelor's degree in geology at UNB, and later returned to school to complete his Ph.D. in planetary sciences. He is currently Canada Research Chair in Planetary Sciences and is also a research scientist for the Geological Survey of Canada. Most of his work focuses on the K-T event as well as meteorite impacts and processes.

According to the main theory dinosaurs became extinct 65 million years ago by the K-T event (Cretaceous-Tertiary Mass Extinction even). The reason being an asteroid or comet hit the earth killing 75% of all species and 90% of all biomass was destroyed. The crater Hildebrand discovered has a diameter of 180km. Finding this crater took many years and was quite an accomplishment.

The Chicxulub Crater

P/Comet Holmes-- breaking news!

On the evening of October 25 was my first viewing of Comet Holmes. This night lab proved to be a wondrous event. We were able to see the comet with and without a telescope!!! A very rare sight.
This periodic comet has never been so bright since its discovery by Edwin Holmes on November 16, 1892. On Wednesday October 24, 2007 P/Comet Holmes grew 400,000 times brighter than the day before- it became visible in Perseus.
It went from a +17 to+3 in apparent magnitude in a few hours. From too faint to see with our Mt A telescopes, to naked eye visibility.
Unfortunately the moon was very bright that evening making it a little more difficult to see.

The key question is how and why did it brighten so rapidly? No one has figured out the answer yet. There has been a huge increase of gas outflow, the reason unknown.
A few possibilities are:

• loss of outer crust
• impact with asteroid, which exposed new ice
• build up of gas inside that broke through crust
• impact with meteoroid stream
• chemical reactions in nucleus disrupted comet
• comet fragmented

Comet Holmes is found between Mars and Jupiter and its distance from the sun is 2.44AU and from the Earth is 1.635AU. It can be seen in the constellation Perseus and will remain there for quite a few months.
Currently Comet Holmes does not show an actual tail, but does have a cloudy region surrounding it which may become a tail. If it does get a tail it will always point away from the sun.
Hopefully it will remain visible for a while longer and will develop a tail.