The Beautiful Cosmos

Open your mind

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An Illustrated Chart for Neil deGrasse Tyson
“The very molecules that make up your body, the atoms that construct the molecules, are traceable to the crucibles that were once the centres of high mass stars that exploded their chemically rich guts into the galaxy, enriching pristine gas clouds with the chemistry of life. We are all connected to each other biologically, to the earth chemically, and to the rest of the universe atomically. It’s not that we are better than the universe, we are part of the universe. We are in the universe and the universe is in us.”
– Neil deGrasse Tyson
Originally Posted on Medium
Submitted by: http://mappleton.tumblr.com/ (Check her out!)

An Illustrated Chart for Neil deGrasse Tyson

“The very molecules that make up your body, the atoms that construct the molecules, are traceable to the crucibles that were once the centres of high mass stars that exploded their chemically rich guts into the galaxy, enriching pristine gas clouds with the chemistry of life. We are all connected to each other biologically, to the earth chemically, and to the rest of the universe atomically. It’s not that we are better than the universe, we are part of the universe. We are in the universe and the universe is in us.

– Neil deGrasse Tyson

Originally Posted on Medium

Submitted by: http://mappleton.tumblr.com/ (Check her out!)

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Really cute and cool vid, watch it!

Submitted by Alicia:

"Hello, Iam a grade 9 student at Dr.knox middle school.My classmates and i have created a video of a weather ballon being sent into space.We would greatly appreciate it if you post the link to your blog. https://www.youtube.com/watch?v=7AoFrgOb-oM

Sincerly: Alicia Bozak, Thank you!”

Filed under Science Space

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A shield only lasts so long

As you may know, our ozone layer protects us from damaging UV rays. This is great considering that UV rays are capable of causing cancer in humans and reproductive problems in animals. However it turns out not only is there a hole in the ozone layer, scientists have also discovered four new man-made gases that seem to be contributing to the depletion of our protecting  shield - the ozone layer.

Layers of the atmosphere (not to scale)

What is the ozone layer?

The image above shows where the ozone layer resides, an area of concentrated ozone. Ozone gas fights both for us and against us, when ozone is at the Earth’s surface, it fights against us, as it is corrosive and harmful to breathe in. When it is concentrated in the lower stratosphere, it fights for us and protects us from the Sun’s damaging UV rays.

If the ozone layer decided to “vanish”, life on Earth would be in big trouble. Exposure to UV rays from the Sun could possibly cause 65% to 90% of melanoma of the skin, cataracts and other damage to the eye and possible other various skin problems that could lead to cancer or even death.

With this in mind it’s not hard to understand why it’s unsettling to hear that there is a hole in the ozone layer.  This hole was discovered by scientists from the British Antarctic Survery in 1985. The cause of the hole is said to be from CFC gases, which were invented in the 1920s and  used in refrigeration and as aerosol propellants in products like hairsprays and deodorants.

This global problem came with a global solution - a total global ban on production that came into force in 2010.

The four new gasses:

The University of East Anglia discovered four new gasses that can destroy ozone. Three of the gases are CFCs and one is a HCFC (hydrochlorofluorocarbon).

"Our research has shown four gases that were not around in the atmosphere at all until the 1960s which suggests they are man-made," said lead researcher Dr Johannes Laube.

The gases were discovered by analyzing polar firn (perennial snow pack). Air extracted from this snow is a natural archive of what was in the atmosphere up to 100 years ago.

Scientists haven’t been able to find out where the new gases are being emitted from yet. The three CFCs are being destroyed very slowly in the atmosphere which means that they will still be around for many decades to come, even if all emissions were stopped now.

Read more here.

Sources:

http://www.nc-climate.ncsu.edu/edu/k12/.ozonelayer

http://www.epa.gov/ozone/science/sc_fact.html

Filed under science ozone layer

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From left to right: Nickel (II) sulfate, Potassium alum, Barium chloride, Copper (II) sulfate, Cobalt (II) chloride, Sodium Chloride and Potassium permangante.

Filed under chemistry science

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Stellar Evolution – The Birth, Life, and Death of a Star

During the day, some of us are lucky enough to be able to look up and see a clear blue beautiful sky and ‘our’ radiant Sun. During the night, most of us can gaze into the night sky and see lots of little bright points, stars. When we look up and see what we call ‘our Sun’, it can be hard to imagine that what we see also looks like this:

Image above: False-colour image of our Sun. Photographed by: Atmospheric Imaging Assembly of NASA’s Solar Dynamics Observatory.

Most of you may look at this and instantly know that it’s a Star. However, there are a fair amount of people who don’t realize that our night sky is full of millions of Stars like this, smaller, bigger and some the same size. Some people don’t know that the Sun is actually a star. I’ve got to admit that the image above looks nothing like what I see with the naked eye when looking up into the Sky:

You’ve probably been told that staring directly at the Sun is bad for your eyes. However, we don’t have to have uncomfortable staring contests with the Stars to try and get them to give up their secrets! After years and years of research, scientists have managed to find out quite a bit about the oh-so-secretive Stars without losing a staring contest.

Firstly, stars go through the same process that we do in the sense that they are born, live and then die. The difference is that they do it far more dramatically and take a much longer time doing it. Depending on the mass of the Star, the lifetime can range from a few million years to trillions of years!

The birth:

Naturally, this is where the comparisons between humans and Stars have to stop. The birth place of a Star is a huge, cold cloud of gas and dust, nebulae/nebulas.

Image above: Chandra, Hubble, and Spitzer image NGC 1952

These clouds begin to shrink, a result of their own gravity. As a cloud begins to shrink it gets smaller and the cloud breaks up into clumps. Eventually, these clumps reach high enough temperatures and get so dense that nuclear reactions begin. When the temperature reaches about 10 million degrees Celsius, the clump becomes a new star, a protostar. A protostar is not very stable. In order to live on, the protostar will need to achieve and maintain equilibrium, a balance between gravity pulling atoms towards the center of the protostar and gas pressure pushing heat and light away from the center. When a star can no longer maintain this balance, it dies.

How do we “know” any of this?

Infrared observatories such as ESA’s Herschel space observatory (launched in May 2009) are able to detect the heat that comes from such stars that we are not able to see, and therefore give us the information we need to research further.

Image above: Artist’s impression of the Herschel Space Observatory

If the critical temperature in the core of a protostar is never reached, it ends up as a brown dwarf, never achieving “star status”. However, if the critical temperature in the core of a protostar is reached then nuclear fusion begins. It is no longer classified as a protostar. It’s defined as a Star in the moment that it begins fusing the hydrogen in the core into helium. Simply put, nuclear fusion is a nuclear reaction where two or more atomic nuclei collide at high speeds and form a new type of atomic nucleus, in this case hydrogen forms helium.

“When a star can no longer maintain this balance, it dies.”

At “Star Status”, Stars spend the majority of their lives fusing hydrogen. So what happens when the hydrogen fuel is gone? Well, the Stars fuse helium into carbon and after a while, into even heavier elements. Maintaining the balance between gravity and gas pressure becomes very hard. The Stars eventually start to collapse on themselves. Before the Star’s inevitable collapse, nuclear reactions outside of the core cause the dying Star to expand outwards and this is what we call the “Red Giant” phase. It really is as dramatic as it sounds.

How dramatic the death is, depends on the mass of the Star. Our Sun is expected to turn into a white dwarf Star. If a Star has a slightly larger mass than our Sun, it may undergo a supernova explosion and leave behind a neutron Star. If even larger, at least three times the mass of the Sun, the Star could even implode to form an infinite gravitational warp in space, a black hole!

Image above: Computer generated image of a Black Hole

Stars live the majority of their lives in a phase that we call the Main Sequence. Our Sun is currently in the main sequence. However, not all the Stars in the Universe are in the main sequence. When we peer into the night sky, we see history. Perhaps you have spotted a few red Stars in the night sky? There’s a chance that the Stars you saw were already dead when you saw them.  Why? Well, these stars are so many light years away that it takes a very long time before the visible light reaches our eyes. When we look up, we are looking at what a Star used to look like X light years ago (X depending on how far away the Star is).

Some stars are only just beginning to form, others are in the Main Sequence and some have begun to die. Luckily for us, there is an amazing diagram, The Hertzsprung – Russell diagram that shows the relationships and differences between Stars:

If you look at the HR-Diagram, you can see many dots. Each dot represents a Star. The Universe has many Stars in it; hence there are many dots on the diagram.

The diagram shows the temperature of the Stars and the Star’s luminosity. The vertical axis represents the Stars luminosity. Luminosity is the amount of energy a Star radiates in one second, where every Star is compared to each other based upon our Sun. Our sun is in the yellow part of the main sequence, and therefore has luminosity 1, all other Stars are compared to ours in this sense.

The horizontal axis represents the Star’s surface temperature, in Kelvin. Here we have higher temperatures on the left and lower temperatures on the right. Usually we go from lower to higher; however, it’s more adequate to see that a star in the upper left corner of the diagram is both hot and bright. A star in the upper right corner of the diagram is both cold and bright, what kind of star would this be? Take a look at the diagram.  Happy Star hunting!

Sources:

http://www.esa.int/esaKIDSen/SEMY06WJD1E_OurUniverse_0.html

http://www.nasa.gov/audience/forstudents/9-12/features/stellar_evol_feat_912.html

http://aspire.cosmic-ray.org/labs/star_life/starlife_main.html

http://essayweb.net/astronomy/blackhole.shtml

http://www.spitzer.caltech.edu/images/2857-sig09-009-NASA-s-Great-Observatories-View-of-the-Crab-Nebula

http://apod.nasa.gov/apod/ap101207.html

http://www.esa.int/Our_Activities/Space_Science/Herschel

http://en.wikipedia.org/wiki/File:Herschel_Space_Observatory.jpg

Filed under Stellar evolution Science Astrophysics

12 notes

Calm down, it’s only Science

In the late 1960′s, gamma-ray bursts were discovered. However, this was not an intentional discovery.  They were discovered by the U.S. Vela satellites that were actually built to detect gamma radiation pulses emitted by nuclear weapons tested in Space! Why? Well, the USA suspected that the USSR might attempt to conduct secret nuclear tests after signing the Nuclear Test Ban Treaty in 1963. However, that wasn’t the case.

On the second of July in 1967, the Vela 4 and Vela 3 satellites detected a flash of gamma radiation unlike any known nuclear weapons’ signature. The team at the Los Alamos Scientific Laboratory (led by Ray Klebesadel) were rather uncertain of what had happened. However, they didn’t consider the matter urgent and filed the data away for investigation.  As more Vela satellites were launched with better instruments, they continued to find these gamma-ray bursts in their data. They analyzed the different arrival times of the bursts as detected by different satellites and the team was able to determine rough estimates for the sky positions of sixteen bursts.

So what were these mysterious outbursts? Was America about to get bombed?

Well, America wasn’t about to get bombed, so that’s one less thing we have to read about in our history books! Instead, it was suggested that the gamma-ray bursts happened inside of the Milky Way Galaxy. This theory was found incorrect when in 1991, the Compton Gamma Ray Observatory, and its’ Burst and Transient Source Explorer instrument was launched. This instrument provided data that showed an absence of gamma-ray bursts in our galaxy and therefore, they had to be beyond our galaxy.

Alright, well, get to the point. Where are gamma-ray bursts?!

Gamma-ray bursts are flashes of gamma rays (electromagnetic radiation of high frequency)  that are associated with very energetic explosions that have been observed in distant galaxies. They are known to be the most radiating electromagnetic events in the Universe. The bursts can last from ten milliseconds to several minutes (a typical burst lasts 20-40 seconds). This is usually followed by an “afterglow” emitted at longer wavelengths such as X-ray, ultraviolet, optical, infrared, microwave and radio.

Picture above: An Artist’s illusion that shows the life of a massive star as nuclear fusion converts lighter elements into heavier ones. Sooner or later, the process comes to and end and the star will collapse and form a black hole. It is theoretically possible that a gamma-ray burst can be formed during the collapse.

There are two different types of Gamma-ray bursts, long and short:

Long gamma-ray bursts: Most of the gamma-ray bursts we have observed, have lasted for longer than two seconds and are then classified as long gamma-ray bursts. Long gamma-ray bursts tend to have the brightest afterglows and are studied in much greater detail than short gamma-ray bursts. From what we have observed, most long gamma-ray bursts are a result of a galaxy with rapid star formation, a core-collapse supernova and generally the deaths of massive stars.

In March 28 2011, there was a very unique gamma-ray burst (GRB 110328A), one that lasted more than two and half months! The event is interpreted as a supermassive black hole devouring a star (probably a white dwarf) and emitting its beam of radiation towards Earth.

Short gamma-ray bursts:

Gamma-ray bursts that have a duration of less than two seconds are classified as short gamma-ray bursts. There are not as many as these as long gamma-ray bursts, only 30 % of those we have observed. Many short gamma-ray burst afterglows have been detected and most of them have been found in regions of little (or non) star formation (such as large elliptical galaxies and the center regions of large galaxy clusters). There have been none that are associated with supernovae. It is believed that they originate from the mergers of binary neutron stars or a neutron star with a black hole.

Picture above: An Artist’s illusion of a gamma-ray burst. The energy from the explosion is shown as two oppositly-directed jets.

So there we have it, no nuclear tests, no blowing up the USA, just a wonderful and fascinating gamma-ray burst!

Sources:

http://astro.berkeley.edu/research/grbs/grbinfo.html

http://www.nasa.gov/mission_pages/swift/bursts/

Illustrated Science Magazine 

Filed under Improved repost Science