10 Science Facts

[Zesh]

I really liked number 7, a star surviving a supernova. +1

[Mordred]

Today's theme: When a star dies it can turn into: #1 White Dwarf

1. A white dwarf, also called a degenerate dwarf, is a stellar remnant composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth.

2. White dwarfs are thought to be the final evolutionary state of all stars whose mass is not high enough to become a neutron star (neutron stars will be the theme of the next fact list) — over 97% of the stars in our galaxy.

3. The material in a white dwarf no longer undergoes fusion reactions, so the star has no source of energy, nor is it supported by the heat generated by fusion against gravitational collapse. It is supported only by electron degeneracy pressure, causing it to be extremely dense.

4. A white dwarf is very hot when it is formed, but since it has no source of energy, it will gradually radiate away its energy and cool down. This means that its radiation, which initially has a high color temperature, will lessen and redden with time.

5. A teaspoonful of matter from a White Dwarf would weigh as much on Earth as an elephant — 5.5 tons.

6. Not all white dwarfs will spend many millennia cooling their heels. Those in a binary star system may have a strong enough gravitational pull to gather in material from a neighboring star.

7. When a white dwarf takes on enough mass in this manner it reaches a level called the Chandrasekhar limit. At this point the pressure at its center will become so great that runaway fusion occurs and the star will detonate in a thermonuclear supernova.

8. Over a very long time, a white dwarf will cool to temperatures at which it will no longer emit significant heat or light, and it will become a cold black dwarf.

9. However, since no white dwarf can be older than the age of the Universe (approximately 13.7 billion years) even the oldest white dwarfs still radiate at temperatures of a few thousand kelvins, and no black dwarfs are thought to exist yet.

10. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun.

 

[Mordred]

Today's theme: When a star dies it can turn into: #2 Neutron Star

1. A neutron star is composed almost entirely of neutrons, which are subatomic particles without net electrical charge and with slightly larger mass than protons.

2. Neutron stars are some of the most compact objects in the universe and due to compression, their surface gravity is phenomenally high, that is about 10^11 times that of Earth! An object falling towards neutron star surface will be accelerated at about 10^12m/s2 which will shred and rip it out into constituent atoms! To escape from a neutron star's surface gravity, one would have to travel at a velocity of 100,000 km/s, that is about one third of the speed of light.

3. For a massive star to become a neutron star, its mass should be greater than 8 times the solar mass but lesser than 20 to 30 times, the mass of our Sun, when it runs out of fuel. If the star is greater than 30 solar masses, it becomes a black hole (black holes will be the theme of the next fact list).

4. The neutron stars are so dense that a spoonful of neutron star will weigh more than a mountain!

5. Neutron stars have very high magnetic fields. The measured magnetic fields are the order of 10^12 Gauss, which is about 10^13 times our Earth's magnetic field!

6. A pulsar (portmanteau of pulsating star) is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. This radiation can only be observed when the beam of emission is pointing toward the Earth, much the way a lighthouse can only be seen when the light is pointed in the direction of an observer, and is responsible for the pulsed appearance of emission. Neutron stars are very dense, and have short, regular rotational periods. This produces a very precise interval between pulses that range from roughly milliseconds to seconds for an individual pulsar.

7. A magnetar is a type of neutron star with an extremely powerful magnetic field, the decay of which powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays.

8. The fastest-spinning neutron star ever found has been discovered in a crowded star cluster near the center of the Milky Way, a new study reveals. The star rotates 716 times per second - faster than some theories predict is possible - and therefore may force researchers to revise their models.

9. In Norse mythology, certain myths claim that Thor's hammer was forged out of a dying star. If we assume that this dying star was a neutron star, it would mean that Thor's hammer (Mjölnir) weighs around the same as 300 billion elephants.

10. Artist's rendition of a neutron star:


 

[Zesh]

9. In Norse mythology, certain myths claim that Thor's hammer was forget out of a dying

'forget' should be forged. I'm really liking this idea and all the facts

[Mordred]

Today's theme: When a star dies it can turn into: #3 Black Hole - Part I/III

1. A black hole is a region of spacetime from which gravity prevents anything, including light, from escaping. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return.

2. Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form. There is general consensus that supermassive black holes exist in the centers of most galaxies.

3. Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe. Astronomers have identified numerous stellar black hole candidates in binary systems, and established that the core of our Milky Way galaxy contains a supermassive black hole of about 4.3 million solar masses.

4. Although once you cross the event horizon you cannot escape the black hole, it is not the main part of the black hole, the destination of the doomed object, or the point at which an object is completely gone. It is only an invisible circle around the black hole that represents the point of no return, where the gravity is too strong to avoid the "hole".  The event horizon can be thought of as an exponentially increasing slope of the hole. The real core of the black hole, the main part, is called the Singularity.  The event horizon is just the space around it.

5. The no-hair theorem states that, once it achieves a stable condition after formation, a black hole has only three independent physical properties: mass, charge, and angular momentum. Any two black holes that share the same values for these properties, or parameters, are indistinguishable according to classical (i.e. non-quantum) mechanics.

6. At the center of a black hole as described by general relativity lies a gravitational singularity, a region where the spacetime curvature becomes infinite. For a non-rotating black hole, this region takes the shape of a single point and for a rotating black hole, it is smeared out to form a ring singularity lying in the plane of rotation. In both cases, the singular region has zero volume. It can also be shown that the singular region contains all the mass of the black hole solution. The singular region can thus be thought of as having infinite density.

7. In 1974, Hawking showed that black holes are not entirely black but emit small amounts of thermal radiation; an effect that has become known as Hawking radiation. By applying quantum field theory to a static black hole background, he determined that a black hole should emit particles in a perfect black body spectrum. Since Hawking's publication, many others have verified the result through various approaches. If Hawking's theory of black hole radiation is correct, then black holes are expected to shrink and evaporate over time because they lose mass by the emission of photons and other particles.

8. Astronomers use the term "active galaxy" to describe galaxies with unusual characteristics, such as unusual spectral line emission and very strong radio emission. Theoretical and observational studies have shown that the activity in these active galactic nuclei (AGN) may be explained by the presence of supermassive black holes. The models of these AGN consist of a central black hole that may be millions or billions of times more massive than the Sun; a disk of gas and dust called an accretion disk; and two jets that are perpendicular to the accretion disk.

9. The deformation of spacetime around a massive object causes light rays to be deflected much like light passing through an optic lens. Observations have been made of weak gravitational lensing, in which light rays are deflected by only a few arcseconds. However, it has never been directly observed for a black hole. One possibility for observing gravitational lensing by a black hole would be to observe stars in orbit around the black hole. There are several candidates for such an observation in orbit around Sagittarius A*.

10. Simulated gravitational lensing (black hole going past a background galaxy):


 

[EMOKDOOM]

Not sure why but I’ve always disliked astronomy and astrology. Too much of it seems far fetch and bs.
But cool idea regardless :]

[WirelessDesert]

This is earth.


Hmm, seems like it loads the picture automatically, here Is the Link, http://farm8.staticflickr.com/7151/6760135001_14c59a1490_o_d.jpg 8000x8000!
Click for a MUCH larger picture. I'm fashinated by this, it's awesome.


On topic: I really like the information you are giving us. Please continue! 

[Mordred]

Not sure why but I’ve always disliked astronomy and astrology. Too much of it seems far fetch and bs.
But cool idea regardless :]

The cool part about science is that it's true whether or not one petitioner, confessedly unworthy, believes in it.

[Mordred]

Today's theme: When a star dies it can turn into: #3 Black Hole - Part II/III

1. To an outside observer with a telescope, an object passing the event horizon will appear to slow down then freeze without ever seeming to pass through the horizon. This is because the light takes longer to escape its gravitational pull and light signals won't reach the viewer for an infinitely long time.

2. If a person was able to survive long enough to describe falling into a black hole, he would at first experience weightlessness as he goes into free fall, but then feel intense "tidal" gravitational forces as he got closer to the center of the black hole. In other words, if his feet were closer to the center than his head, then they would feel a stronger pull until he eventually is stretched and then ripped apart.

3. A Wormhole, known alternatively as a Lorentzian wormhole, Schwarzschild wormhole or Einstein-Rosen bridge, is a theoretical opening in space-time allowing a "shortcut" through intervening space to another location in the Universe. However, from the outside wormholes may exhibit many of the characteristics usually associated with a black hole and might be virtually impossible to tell apart.

4. Black holes don’t fill up because they are already essentially a geometric point, with effectively infinite density. There is no limit to the mass of a black hole.

5. All the matter in the Universe will not end up in black holes. Most stars in the Universe don’t have enough mass to become black holes at the end of their lives. Neutron stars and white dwarfs are much more numerous; this is what most stars end up as. Black holes are not cosmic vacuum cleaners, they will not suck up everything in the Universe, and they only suck up what crosses their event horizons.

6. The nearest black hole was believed to be not such a nearby object and was observed by observations of strong X-ray emissions from Cygnus X-1, located about 8000 light years away.

7. More recently (1999) we've discovered another black hole that lies just 1,600 light-years from Earth on the way to the center of the Milky Way in the direction of the constellation Sagittarius and is associated with a visible star called V 4641. It is being called a micro-quasar because it showed the brilliant behavior associated with quasars (Quasars are a particular model of black hole which will be discussed in tomorrow's list!).

8. When two black holes collide they don't actually impact each other in the physical way. They just merge and form a new black hole (or it might be the case that one of them "eats" the other one) which grows in mass and strength from their original constituents. The merging usually happens after the lighter black hole has orbited the heavier black hole for some time (between 50 and 100.000 years).

9. White Holes have been talked about but are very hypothetical. They are supposed to be what comes out from the other side of a black hole and where all the mass that goes into the black hole goes to. As I have already said a black hole tends to get bigger as more mass goes in, so really mass just gets added to the black hole and there is no real need for a White Hole. If White Holes did exist (and there’s nothing saying they don’t) then they could be a connection to a parallel universe (most likely scenario due to how a black hole interacts with the fabric of space time) or a distant region of space (it might even be possible that they link to a moment in the future, however that is unlikely). Mathematics does say that black holes and white holes could exist but they would only probably exist for a very short period of time. No White Holes have been observed until now in our Universe, however scientists working on this have recently claimed that this is because each Universe (as part of the Multiverse) has only one White Hole - the Big Bang! I.E. If this theory is correct, inside the core of each black hole there is a new Universe.


 

[Mordred]

Today's theme: When a star dies it can turn into: #3 Black Hole - Part III/III

1. A quasi-stellar radio source ("Quasar") is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than extended sources similar to galaxies.

2. While the nature of these objects was controversial until as recently as the early 1980s, there is now a scientific consensus that a quasar is a compact region in the center of a massive galaxy surrounding its central super-massive black hole. Its size is 10–10,000 times the Schwarzschild radius of the black hole. The quasar is powered by an accretion disc around the black hole.

3.  Quasars are by far the brightest objects in the Universe. When astronomers first calculated the energy output of quasars, many of them didn't believe anything could emit that much energy, however analysis of the two jets that emanate perpendicularly to the host galaxy (see picture below) confirmed their computations on emitted energy.

4. At the center of a quasar, the black hole is surrounded by a large, rotating cloud of gas. As the gas falls into the black hole, it is heated up to millions of degrees. The gas emits thermal radiation due to its enormous heat. This thermal radiation spans the spectrum, making the quasar bright in the visible spectrum as well as x-rays.

5. The gravitational force from the black hole is so strong, and pulling so much gas, that the gas glows brighter than the surrounding galaxy. Not all the gas is able to find its way into the black hole; much of it escapes and is carried off by strong winds blowing out from the center for the quasar.

6. The most luminous quasars radiate at a rate that can exceed the output of average galaxies, equivalent to 2 trillion (2×10¹²) suns. This radiation is emitted across the spectrum, almost equally, from X-rays to the far-infrared with a peak in the ultraviolet-optical bands, with some quasars also being strong sources of radio emission and of gamma-rays.

7. More than 200,000 quasars are known, most from the Sloan Digital Sky Survey. All observed quasar spectra have redshifts between 0.056 and 7.085. Applying Hubble's law to these redshifts, it can be shown that they are between 600 million and 28.85 billion light-years away (in terms of proper distance). Because of the great distances to the farthest quasars and the finite velocity of light, we see them and their surrounding space as they existed in the very early universe.

8. Because quasars are extremely distant, bright, and small in apparent size, they are useful reference points in establishing a measurement grid on the sky. The International Celestial Reference System (ICRS) is based on hundreds of extra-galactic radio sources, mostly quasars, distributed around the entire sky. Because they are so distant, they are apparently stationary to our current technology, yet their positions can be measured with the utmost accuracy by Very Long Baseline Interferometry (VLBI); positions of most are known to 0.001 arc-seconds or better, orders of magnitude more precise than the best optical measurements.

9. One of the most important facts about quasars is that they are all very distant from us. The closest quasar is about 800 million light years away. Therefore, we can conclude that there are no quasars in the universe today and the last quasar disappeared about 800 million years ago. Where did the quasars go? No one can say for sure. Given their power source, however, it is most likely that they simply ran out of fuel. The black holes eventually consumed all the gas and dust in the disk surrounding them, so the quasars ceased to shine, however that means only the death of the quasar, and not of the black hole. Most likely galaxies that lose their quasar just become a normal galaxy with a super-massive black hole at the center.

10. Artist's rendition of a galaxy with an active quasar - emission jets (north and south pole of the super-massive black hole in the center) are to scale:


BONUS
11. The X-ray image of the quasar PKS 1127-145, a highly luminous source of X-rays and visible light about 10 billion light years from Earth, shows an enormous X-ray jet that extends at least a million light years (the Milky Way galaxy is 100.000 light years across) from the quasar (actual picture!):



 

[Mordred]

Today's theme: Various

1. When glass breaks, the cracks move at speeds of more than 4,500 km/h (3,000 miles/h).

2. The most powerful lasers are made with Neodymium-doped Yttrium crystals. In a fraction of a second, they produce more power than the whole United States.

3. If you yelled for 8 years, 7 months and 6 days, you would have produced just enough sound energy to heat up one cup of coffee.

4. Due to gravitational effects, you weigh slightly less when the moon is directly overhead.

5. The lightning bolt is 3 times hotter than the Sun.

6. If an atom were the size of a stadium, its electrons would be as small as bees.

7. The effect of Special Relativity (discovered by Albert Einstein) made astronaut Sergei Avdeyev a fraction of a second younger upon his return to Earth after 747 days in space.

8. The diameter of a proton (you can find them in the nucleus of atoms) is approximately 0.000000000001 mm (1/25,000,000,000,000 inch).

9. All things around us are made up of atoms. They are so incredibly small that about 100,000 atoms would fit inside a period such as the one at the end of this very sentence.

10. It is estimated by scientists that the oceans on Earth contain about 20 tons of gold. This gold, however, exists in small non-extractable amounts.

[Stackprotector]

nice

[Mordred]

Today's theme: Chemistry

1. Chemistry is the study of matter and energy and the interactions between them. It is a physical science that is closely related to physics, which often shares the same definition.

2. Chemistry traces its roots back to the ancient study of alchemy. Chemistry and alchemy are separate now, though alchemy still is practiced today.

3. All matter is made up of the chemical elements, which are distinguished from each other by the numbers of protons they possess.

4. The chemical elements are organized in order of increasing atomic number into the periodic table. The first element in the periodic table is hydrogen.

5. Each element in the periodic table has a one or two letter symbol. The only letter in the English alphabet not used on the periodic table is "J". The letter "Q" only appears in the symbol for the placeholder name for element 114, ununquadium, which has the symbol "Uuq". When element 114 is officially discovered, it will be given a new name.

6. At room temperature, there are only two liquid elements. These are bromine and mercury.

7. The IUPAC name for water, H₂O, is dihydrogen monoxide.

8. The discoverer of an element may give it a name. There are elements named for people (Mendelevium, Einsteinium), places (Californium, Americium) and other things.

9. Most elements are metals and most metals are silver-colored or gray. The only non-silver metals are gold and copper.

10. Although you may consider gold to be rare, there is enough gold in the Earth's crust to cover the land surface of the planet knee-deep.

[Mordred]

Today's theme: Chemistry

1. In the early 1940s a large portion of the world’s plutonium supply was accidentally ingested by a lab technician. The majority of plutonium, like other heavy metals, passes right through your digestive tract. Don’t ask how they recovered all that plutonium…

2. Did your high school tell you there are three states of matter? Solid, liquid, gas. Or Maybe they threw in a fourth state, plasma. In fact, there are many more than just three or four states of matter. Around absolute zero a lot of funny things happen and new states of matter pop up, like Bose-Einstein condensates which defy gravity.

3. Watson and Crick, the co-discoverer’s of the DNA double helix never actually ran any experiments on their own, but rather read deeply into others’ work and deduced the structure.

4. Lithium can alter how you think and has been known to “cure” certain mental illnesses. In fact, lithium is used in a lot of psychoactive drugs.

5. One of the first X-rays, a picture you’ve probably seen of a woman’s hand with a ring on it, was of Bertha Rontgen’s hand. She thought seeing her bones was a death omen.

6. Hot water freezes quicker than cold water.

7. People used to drink radioactive water from a device called the “Revigator.” It was considered to be a healthy drink.

8. Diamonds aren’t the rarest gems on Earth. In fact, they’re relatively common. The rarest gem is jadeite and costs about $3 million per carat.

9. Only 28 grams of the rarest substance on Earth exist. What’s the rarest substance on Earth? Astatine.

10. Gallium, a metal element, will melt in your hand. You can even buy some here: http://unitednuclear.com/index.php?main_page=product_info&cPath=87&products_id=142

[Mordred]

Because sometimes I want to offer you guys something more consistent to digest, I have a category called "SPECIAL" in which I replace the 10 facts with a (in my opinion amazing) picture and a short story about what you can see in there.

I like doing this type of post also because it offers me the possibility to show you, for real, exactly what the world you live in looks like.



Today's theme: SPECIAL - Wonders of the Universe



This is the globular cluster NGC 1850; it is located about 163,000 light-years away in the Large Magellanic Cloud in the constellation Dorado.

The Large Magellanic Cloud (LMC) is a nearby irregular galaxy, and a satellite of the Milky Way. At a distance of slightly less than 50 kiloparsecs (~163,000 light-years), the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal (~16 kiloparsecs) and Canis Major Dwarf Galaxy (~12.9 kiloparsecs) lying closer to the center of the Milky Way.

It has a mass equivalent to approximately 10 billion times the mass of our Sun (10¹⁰ solar masses), making it roughly 1/100 as massive as the Milky Way, and a diameter of about 14,000 light-years (~4.3 kpc). The LMC is the fourth largest galaxy in the Local Group, after the Andromeda Galaxy (M31), our own Milky Way Galaxy, and the Triangulum Galaxy (M33). The object itself is interesting and peculiar in a few different ways...

Firstly, it's surrounded by nebula-like material that kind of resemble Star Trek shields in some images. Many astronomers believe this material was generated during supernova events throughout the cluster’s history.

Secondly, the cluster is actually two clusters. You have the main globular cluster; the large, sprawling structure that probably first grabbed your attention when you first gazed upon the image. Tucked away near the bottom corner is a second, much smaller cluster of stars. The smaller cluster is part of the main cluster (meaning the smaller structure is gravitationally bound with the larger structure instead of being in the fore/background) and is composed of both massive, hot blue stars and smaller, cooler red stars. This kind of diversity gives scientists an opportunity to study the various different aspects of star-formation.