Extrasolar Planets

The status of Pluto as a planet was never entirely certain for over 75 years since its discovery. It is the tenth largest planetary object in order of ascending size, right after dwarf planet Eris. Our former ninth planet was discovered by Clyde W. Tombaugh on February 18, 1930, and it is the most widely recognized dwarf planet in our Solar System, and the Kuiper belt's largest object. Pluto's status as the ninth planet from our Sun was reviewed in 2006 due to an International Astronomical Union debate on how to classify such large objects. Even up to this current day and age, despite its status demotion to dwarf planet, Pluto is still widely regarded as a favorite among planetary objects in our Solar System and these provocative photographs were taken as firsts by the New Horizons satellite just last year to finally show just how much of a mysterious and puzzling place it really is.

The New Horizons space probe was designed by NASA to study the extreme conditions of dwarf planet Pluto and its natural satellite Charon, about 3.6 billion miles away from our Sun. This mission, not unlike NASA's Messenger probe, which also finalized a journey to explore the innermost conditions of our Solar System near Mercury earlier the same year, took nine and a half years to complete since its launch in January 19, 2006. The New Horizons satellite was successful at localizing and imaging Pluto and its moon, also detecting many surprising and familiar surface features including an atmosphere, glaciers, mountainous regions, great plains, and even water ice distributed all over its surface terrain. Arriving at Pluto has appealed to our collective sense of bewilderment for reminding us about how beautiful and exciting rediscovering a foreign planet really is.


Pluto with its moon Charon on the left as New Horizons quickly approaches its main objective (Image: NASA).

In the midst of this first look at Pluto as our ex-ninth planet, we now have theories of a new extrasolar object, harboring ten times the gravity on Earth and a wondrously eccentric orbit, located right outside our Solar System. The ninth planet spot is now more coveted than ever!

General Relativity

Published in 1916, the general theory of relativity is often regarded as Albert Einstein's greatest achievement and one of the most remarkable scientific contributions of the 20th century. It is known for redefining gravity beyond the previous Newtonian interpretation and describing it as a geometric property of space-time. General relativity is viewed as an expansion of the special theory of relativity and it differs from the special case because it takes into account the motion due to gravitational fields and other accelerating reference frames, thought to be similar according to the equivalence principle. Along with quantum theory, general relativity is considered to be a central pillar of modern physics and is currently accepted as the leading theory for gravitation.


Earth's mass warps space-time and shapes the Moon's geodesic orbit (Image: NASA).

General relativity describes the attractive force of gravity as being the result of an acceleration produced when something interacts with curved space-time, usually there because of an object with a very large mass. The more mass an object has, the more it warps the space-time around it and the larger its gravitational field is. Any object with some mass or just energy is thought to have a gravitational influence as well but will always experience an attractive pull when it is close enough to another object with a sufficient amount of gravity. Even rays of light that approach a gravitational field will bend towards it in a phenomenon known as gravitational lensing. This effect was confirmed to exist when the light from stars behind the Sun was observed to travel around it during the total solar eclipse of 1919.

Other tests of general relativity include the observation of a gravitational redshift in visible light emerging from a gravitational field, which loses energy and increases its wavelength, shifting towards a redder color. When entering a gravitational field, it behaves in the opposite way by gaining a shorter wavelength and a bluer appearance. Gravitational redshift was first measured in the light emitted by white dwarf star Sirius B in 1925. When a very massive object rotates on its axis, it will also twist the space-time around it as it spins. This is known as frame-dragging and it too was confirmed to exist by observing the orbital shifts that emerged from satellites traveling around our planet. General relativity predicts the existence of gravitational waves, which are ripples in space-time that propagate at the speed of light and are caused by sudden changes in an object's gravitational field, but their direct detection is currently a subject of on-going research.

From the smallest interaction of an elementary particle to the behavior of the cosmos itself, Albert Einstein's ideas have altered the way we view our physical surroundings on many scales. While general relativity accurately describes the gravitational attraction between celestial objects, it is additionally useful for describing other processes such as the expansion or contraction of a universe. Exotic objects such as black holes, white holes, and wormholes are also predicted to exist according to the equations of general relativity. Einstein's dream was to find a theory of everything that could combine the fundamental interactions of nature, specifically gravity and electromagnetism, to show that they were all facets of the same unified force. The search for a theory of everything continues to this day with the goal of bringing together Einstein's laws of general relativity with those of the quantum world in order to develop a consistent theory for quantum gravity.

Robotic Vehicles on Mars

Interest in exploring the Red Planet started with the first robots designed to investigate it in the 1960s, and continues today with the Mars Science Laboratory rover Curiosity, where recent efforts have shown to be what looks like evidence of an ancient riverbed and organic compounds on the Martian surface. Organic compounds are those with molecules containing carbon and are potential indicators of life.


Mars and Earth riverbeds in comparison (Image: NASA).


A landscape of Mars captured by Pathfinder in 1997 (Image: NASA).

Mars is the fourth planet from our Sun and is believed to be about 10.7% the mass of Earth and approximately half of its size. It is currently thought that sustainable life on Mars may be possible and might have existed there a long time ago, if Earth and Mars share similar planetary histories. We know that they both have polar ice caps, an atmosphere, and exceptional terrain features. With several vehicles set to test for habitability on Mars in the future, humans will be able to properly assess whether a manned mission to Mars prevails as a safe and advantageous exploration plan.

Particle Accelerator by CERN

Tonight, I write to express my interest in Earth's largest operating machine. The Large Hadron Collider is the most complex scientific instrument in use today. It is run by the European Organization for Nuclear Research (CERN) and it is buried 574 ft (175 m) below ground on the border of France and Switzerland, near Geneva, Switzerland.


The LHC can be found buried underground in Europe (Image: CERN).


The central LHC accelerating ring. It spans a 5.3 mile long (8.6 km) diameter (Image: CERN).

When powered up, the LHC releases beams made up of protons or other ions through a series of interconnected ring-shaped tunnels. Accelerated by giant superconducting magnets, the particles reach speeds approximating 99.9% the speed of light. As they approach the largest ring (highlighted in yellow), which is nearly 17 mi (27 km) in circumference, engineers collide the particles in testing rooms the size of warehouses. Results are then recorded by sensors placed in these rooms and studied in order to provide useful information about the nature of the particles that belong to the standard model of particle physics. Scientists and engineers examine the results of current research efforts either to try to prove the existence of the Higgs boson, the key to the origin of mass in the universe, or to gain additional knowledge regarding the dynamics of subatomic particles.


Engineers working inside the LHC (Image: CERN).

Engineers have been maintaining and upgrading the LHC ever since achieving the first successful particle beam circulation in September of 2008. This year, on March 30, 2010, the LHC broke the record for the highest-energy man-made collision event ever planned between two 3.5 teraelectronvolt beams. It might also be able to shed light on the unification of fundamental forces, such as that of the electroweak interaction, found at very high temperatures. With a maximum operating energy of 14 TeV, the LHC is set to advance a new era in physics over the next few years.