Hello and welcome to my blog about my life (science) and whatever else takes my fancy (hint: it's more science). You may call me Dougal and I'm 19 Earth years old, currently double majoring in physics and chemistry in New Zealand. In reality I have no idea what I'm doing or what I'm going to do though so you'll find a little bit of everything.
A Planet Full of Water
But psyche! The water only exists either as steam or as ice, while this may come as a contradiction of sorts, the extremely high pressure on this planet causes the water to exist in a solid form. The planet named GJ1214b has a diameter nearly 3 times as great as Earth and weighs 7 times as much. The planet is also 40 LY from our sun. The measurements from the planet are calculated by the effect light has in the planet’s atmosphere.
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Stellar Explosions in the Lab
When an experiment consists of magnetism and plasma flying at 50 km/s you know it’s got to be good. A recent experiment conducted at Caltech involves these and more.
The experiment itself was conducted to better understand coronal mass ejections which form when magnetic fields “snap” and reconnect, expelling incredibly hot plasma in the process. Another phenomenon known as a Kink instability was also present. As the plasma is essentially 20,000 Kelvin gas of charged particles (with a current of 100,000 Amps) it generates a magnetic field as it moves. This magnetic field affects the charged particles in return, causing them to spiral and cork screw, which can be seen in this picture.
The Kink instability also begets another instability known as the Rayleigh-Taylor instability (which is also what causes the tendrils on the inside of the Crab Nebula) which forms when a dense fluid attempts to move through a less dense fluid, in this case the dense plasma through the lower density vacuum that trails it, causing the ripples seen.
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Two New Moons Found Orbiting Jupiter
Two new moons have been found orbiting Jupiter, bringing the Jovian family count up to 66 natural satellites.
Currently known as S/2011 J1 and S/2011 J2, the new moons were first identified in images acquired with the Magellan-Baade Telescope at the Las Campanas Observatory in Chile on September 27, 2011.
The objects are among the smallest moons yet discovered in the solar system, each measuring only about a kilometer (0.62 mile) wide.
Unlike Jupiter’s four large Galilean moons, which are visible from Earth with even small backyard telescopes, both new moons are dim and very distant from the planet, taking about 580 and 726 days to complete their orbits.
Due to their odd orbits, the moons are likely asteroid or comet pieces that were long ago captured by Jupiter’s gravity rather than developing in place during the formation of the planet itself.
Why Do We Only See One Side of the Moon?
Every 29.5 days the moon both completes one rotation about its axis and one orbit around Earth. This may strike you as an odd coincidence or even something of a miracle. It however is neither of these, but rather an almost unavoidable consequence of gravity. When the moon was first formed it rotated much faster than it did now and was also much hotter. The thing that may not be obvious to you is that not only does the moon cause tides on Earth, but the Earth causes tides on the moon. Of course not of water, but rather of the rock itself, this means that the moon bulges like an ellipsoid both towards us and away from us. It was this bulge that robbed the moon of angular momentum by converting it into heat through friction due to the moon’s contraction and expansion. In a way it’s this same principle that may lead to liquid under the surface of Titan by creating enough friction to melt water. Over time the moon will have this same effect on the Earth and it will have a day lasting 29.5 current days, but that’s a long way off!
Images: moon’s near side, moon’s far side.
As a star comes towards the end of its life it begins to expand as the energy released increases the outward pressure of the plasma causing it to become a red giant. This star then goes through a series of expansions and compressions shedding layers rich in carbon in nitrogen as it goes. More massive stars have a more impressive ending, their death throes come in the form of a super nova where their shells are exploded off often leaving nothing but an incredibly dense neutron star.
Images: NASA/ESA/ESO
The Hertzspring-Russell Diagram is a chart that shows the relationship between luminosity and colour of stars. The chart itself contains information for about 23,000 nearby stars and illustrates the fact that stars only fall within certain allowed regions of the diagram.
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Just a neat little animation showing the apogee and perigee (the moon’s equivalent to aphelion and perihelion) of the moon as viewed from Earth. Also it reminds me of Majora’s Mask.
Elliptical Orbits
Just about every popular depiction I’ve ever seen of the solar system has the planets either in a straight line or in circular paths. In fact one humorous (but not satirical) book I own entitled LIFE HOW DID IT GET HERE? By evolution or by creation? goes so far as to compare the orbits of planets to the “orbit” of electrons around around a nucleus (the Bohr model no less) as evidence of God’s existence and apparent intelligence. In truth the planets do not follow these nice circular orbits instead they’re drawn out into ellipses. While on Earth this isn’t noticeable (our orbit only has an eccentricity of about 0.02) with comets and protoplanets such as Pluto this is hugely noticeable.
The idea of an elliptical orbit was first put forward by Johannes Kepler and was a major shock to astronomy at the time as it was believed that circular orbits were “perfect” and infallible. Within the orbit itself the larger of the bodies is situated on one of the ellipse’s foci. The other foci is empty space, but is the center of gravity determined by other objects such as planets or even distant galaxies, in fact by everything in the universe. The elliptical orbit also has the interesting affect of causing the orbiting body to change speed depending on where it is in its orbit. This means that when the planet or comet is closest to the sun (a point known as the perihelion) it is traveling faster than it is at the point farthest away (the aphelion).
The Van Allen Belts
The Van Allen belts are two strips surrounding the Earth composing of radiation trapped by the Earth’s geomagnetic field. They’re doughnut-like (toroidal) in shape and the outer belt extends about 60 000 km above the Earth’s surface. Due to their composition of charged particles they can pose a major hazard to satellites that spend too much time within them by disturbing their electrical components.
The closest the inner Van Allen Belt makes it to Earth is in a region called the South Atlantic Anomaly. Satellites that pass through this region need extra shielding to cope with this, the Hubble does not take pictures when passing through and astronauts have reported seeing phosphenes (lights in your eyes) when in this region. Aside from electrons, protons and various ions, it’s also suspected that the Van Allen belts could contain traces of antimatter
The image above shows simulated Van Allen belts in a 1966 Electric Propulsion laboratory experiment.
The Platonic Solids
A Platonic solid is a convex geometric shape made entirely of congruent, regular 2D sides. This may seem like it leaves a lot of room for experimentation, but no matter what you try there are only 5: the tetrahedron, hexahedron (cube), octohedron, dodecahedron and the icosahedron (shown in order). The name comes from the famous Greek philosopher Plato, who described the classical elements in terms of these polyhedra with cubes representing earth, tetrahedra as fire, air by octahedra and the icosahedron represented water. The dodecahedron was said to be the material that made the Heavens, an idea that would go on to become that of the aether.
The German astronomer Johannes Kepler also held a fascination with them, believing that the 5 known planets some how corresponded to the 5 platonic solids. As such he became obsessed with forming a model of the solar system where the orbits of the planets were defined according to the geometries of these shapes. Kepler was however forced to abandon this idea but these concepts gave rise to the discovery of elliptical orbits.
The other cool thing about Platonic solids is that each has a dual pair that is another Platonic solid. This means that the vertices of one shape correspond to the faces of another, for example the cube and the octahedron. Some Platonic solids (the cube, octahedron and tetrahedron) also form the basis of crystal structures along with being the body shape of several species of radiolarian (smaller protozoa that form their own mineral skeletons).
CALLING ALL PHYSICISTS, COSMOLOGISTS AND GENERALLY SMART PEOPLE.
Okay. So I’m asking you guys for some help. Help to solve a problem I’ve devised and can’t come up with the correct answer on my own (hence why I named it after myself, go me). So here goes…
On the event horizon of a black hole you should expect electromagnetic radiation to be stuck there and not moving. Therefore you can conclude that its velocity is equal to zero. However, the relationship of v=fλ must equal zero. This means that either the waves frequency (f) or wavelength (λ) must equal zero. The interesting thing about this is the energy involved (calculated by E=hf, where h is Planck’s constant) has two values. If f=0 then E=0, if λ=0 then the wave has an infinite amount of energy (due to rearranging v=fλ to give v/λ=f and substituting to give E=h(v/ λ)). Both these answers are of course paradoxes.
So smartypants, what is going on here?
Psychedelic Asteroid
This picture shows the varying mineral compositions of Vesta and was taken by NASA’s Dawn spacecraft. Vesta is one of the largest asteroids with a diameter of 530 kilometres (330 miles). This image also shows that Vesta has a composition more like a planet rather than other asteroids which is an interesting find.
