And that’s why you should buy a phone. The only reason.
And that’s why you should buy a phone. The only reason.
From left to right: Nickel (II) sulfate, Potassium alum, Barium chloride, Copper (II) sulfate, Cobalt (II) chloride, Sodium Chloride and Potassium permangante.
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:
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!
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.
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.
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!
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:
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!
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!
Illustrated Science Magazine
My most recent article regarding extra-terrestrial life. I am now writing for this website, but I shall continue to post here too.
Wait, what? Who? How do you even pronounce that?
With great difficulty!
Gustav Robert Kirchhoff was born on the 12th March (that’s right, today!) in 1824 and died on the 17th October 1887. He was a German physicist who contributed to the fundamental understanding electrical circuits, spectroscopy, and the emission of the black-body radiation by heated objects.
In 1862, he coined the term “black body” radiation, and the Bunsen-Kirchhoff Award for spectroscopy is named after him and his colleague, Robert Bunsen.
Kirchhoff also has a fair amount of laws named after him:
Good article, explains the basics of how we hear. Just going to add that sound waves are mechanical waves that can only travel through solids, liquids and gasses. Unlike electromagnetic waves, that can travel through a vacuum. Light is an example of an electromagnetic wave, as we can see the sun and stars.
..if you wish to see the planets with detail! They may help you by preventing you from being wiped off of the face of the Earth by a bus, but when it comes to inspecting the Moon and making conspiracy theories to as why there appears to be a face on the Moon.. You’ll need a telescope!
In the picture above we see the great Sir Patrick Moore with his 15ins telescope at his house in Farthings, Selsey, 30 years ago. I’m going to assume that most of you have heard of Patrick Moore, especially after the unfortunate, yet inevitable, death. You may also know that he was an English amateur astronomer that was indeed quite fond of telescopes.
However, this article isn’t focusing on Patrick Moore, but more on how telescopes work and the different types of telescopes. If you wish to read up on him, then this is quite a good article.
Different types of Telescopes? Surely you’re not telling me that there’s MORE than one type of Telescope?!
You have much to learn, young Padawan. There are many different types of telescopes: Optical telescopes, Radio telescopes, X-ray telescopes, Gamma-ray telescopes, High-energy particle telescopes, etc. I’m going to focus on Optical telescopes and there are three main types of these: Refractors, reflectors and the compound/catadioptric telescope.
The type of telescope is determined by the part of the telescope that gathers light. This part is called the objective. Refractors use a glass lens as its objective, so that the glass lens is at the front of telescope and light is bent/refracted as it passes through this lens. A reflector uses a mirror instead as its objective. The mirror is close to the rear of the telescope and light is bounced off/reflected off as it strikes the mirror. Compound telescopes use both mirrors and lenses to collect and focus the incoming light.
Which one is the best telescope for me?
Well, it depends on what you’d like to see. Refractors are known for sharp, detailed and well-contrasted images. They are said to be best for viewing the moon and planets. A small refractor of 60 mm to 80 mm aperture will make a good starting scope to observe the Moon and planets. They’re portable and inexpensive and a refractor is possibly the best choice if you will be doing most of your observing from the city or suburbs, where there is light pollution.
Newtonian reflectors are great-all around scopes that aren’t too expensive either. You can view both planetary and deep-sky viewing; however, these scopes are more fragile and require more maintenance than the others.
Compound telescopes/catadioptrics are said to be the most versatile telescopes and have the best all around, all-purpose design. They tend to be very portable and compact, and if you use them in the right situations (away from light pollution with a clear night sky), then you should be able to see excellent views of the Moon, planets and faint deep sky objects such as clusters, galaxies, nebulae comets, etc. This is probably the most suited telescope for astrophotography, yet you’ve got to pay the slightly expensive price for one of these.. However, to quote spacephilosopher “You lose your house, but you get the Universe”.
Unfortunately, telescopes don’t float around in the air and position themselves perfectly for us… yet. They need to be supported by some type of stand, or mount, unless you feel like doing a bit of weight-lifting. There are two basic types of telescope mounts: Alt-azimuth and Equatorial.
The alt-azimuth mount is similar to a camera tripod, it uses a vertical (altitude) and a horizontal (azimuth) axis to locate an object. This type of mount is simple to use, but it doesn’t track the motion of stars properly. When it tries to, it produces a “zig-zag” motion instead of a smooth arc across the sky. This makes this type of useless for taking photographs of the stars.
The equatorial mount uses two axes (right ascension, or polar, and declination) aligned with the poles to track the motion of an object across the sky. Instead of being orientated up and down, it’s tilted at the same angle as the Earth’s axis of rotation.
The Sky at Night book - Sir Patrick Moore & Chris North (Worth buying)