What We Know About Planets

What We Know About Planets Ormel and Kobayashi state that considerable time and mass are required to form a gigantic planet (1). In 1990, scientists discovered a planetary system around a millisecond pulsar. Later on, the scientists were able to measure the movement of the 51 Peg star (i.e. 5th magnitude star) located in the constellation of Pegasus.Advertising We will write a custom essay sample on What We Know About Planets specifically for you for only $16.05 $11/page Learn More This discovery marked the first evidence of the existence of exoplanets (planets surrounding other stars). Since then, astrologists have discovered the existence of numerous exoplanets (Havel et al., 1). For instance, Sahlmann and others employed the radial-velocity method to detect the existence of extrasolar planets (1). Discovering other Planets Many astrologists find it extremely hard to capture straight images of exoplanets. This is because they must observe the light reflected by the far-flung parent star. The imaging is compounded further by the fact that the light projected by an exoplanet is million of times weaker than the parent star itself. Thus, exoplanet imaging is comparable to an attempt to spot a moth moving around a lighthouse from several miles away. Astrologists have (in the past few years) spotted a number of exoplanets as direct sources of the reflected light. In reality, these are far-flung gigantic planets which are orbiting their own solar systems. Thus, the direct imaging of exoplanets remains an extremely complex task which may take a long time to accomplish (Perryman 1). On the other hand, astrologists have been able to ascertain the existence of exoplanets by detecting their properties using astronomical telescopes mounted in the space and ground (Sahlmann et al., 1). One of the most effective strategies used to spot an exoplanet is detecting the manner in which the gravitational force of the planet acts on the parent star. Scientists can measure the gravi tational force of an exoplanet because both the parent star and the planet orbit their respective centre of mass. Since the parent star has substantial mass, it experiences a smaller tremble compared to the exoplanet. However, both the star and the planet have an identical orbital period. Thus, astronauts are able to detect the presence of an exoplanet (i.e. The star’s Doppler shift) by examining the wavelength of shadowlike lines produced by the star over an extended period of time. The technique explained above must be repeated several times in order to detect an exoplanet. This technique has enabled astronauts to discover over 200 planets to date. In addition, approximately 10 percent of the stars visible to the human eye are surrounded by exoplanets (Kasting 1).Advertising Looking for essay on astronomy? Let's see if we can help you! Get your first paper with 15% OFF Learn More Astronauts are currently using the velocity of the parent star to deter mine the mass of the exoplanet. It is important to note that scientist discovered the first exoplanet in 1999 via a high-tech spectroscopic measurement gadget. Currently, the findings by several astronomical instruments such as the US HIRES (Keck 10-m) telescope located in Hawaii have facilitated the discovery of planets with masses comparable to that of the Earth. Scientists have also found that it is possible to spot an exoplanet that has mass corresponding to that of the Earth if the velocity of the host star is computed with a precision of approximately one meter for every second. Astronauts have also detected the presence of a star by examining the light it generates. For instance, the targeted star can be detected from the microscopic reduction in the brightness of the parent star when the planet happens to move across its face. The result is synonymous to the transit of the Venus as gleaned from the earth. Although astrologists are able determine the variation in brightness, they are nonetheless not capable of detecting the transit of the planet across the parent star. Although the transit mark (dimming) can be visible for several hours, the star must be screened for several years in order to detect a recurring pattern (which implies the existence of an excellent). It deserves merit to mention that the photometric transit technique has facilitated the discovery of over 100 exoplanets ever since 1999. Some of the exceptional breakthroughs are those of the US Kepler Satellite (set up in 1999), French-led CoRot Satellite, and the UK-led WASP Satellite (Ormel and Kobayashi 2). There are two reasons why astrologists appear to favour photometric transit technique in detecting exoplanets. First, they can use the Doppler measurements to compute the planet’s mass on the basis of the gravitational force exerted on the host star. Second, the diameter of an exoplanet can be computed using the microscopic amount of dimming as it moves across the face of the p arent star. Thus, the degree of the dimming will be higher if the exoplanet in transit is gigantic. Astrologists can use these planetary characteristics (mass and size) to approximate the density of the planet. In addition, it is possible to ascertain the atmosphere and chemical compositions of a star by monitoring variations in the spectrum of the parent star. Astrologists are now able to partially determine the constituents of the exoplanet atmosphere (Kasting 1). The Creation of Planetary Systems Pierre-Simon Laplace, Immanuel Kant and Emmanuel Swedenborg are among the first scientists to propose theories relating to the formation of the planetary system. For instance, Laplace proposed that gravitational force caused nebulae (gaseous rings) to gradually rotate, crumple and even out resulting in the formation of planets.Advertising We will write a custom essay sample on What We Know About Planets specifically for you for only $16.05 $11/page Learn More In other words, Laplace’s theory suggests that planets emerged as a result of the disintegration of a distinct system of gaseous clouds wherein impulsive gravitational force resulted in the formation of planets. However, the theory was discarded in the 20th century since it did not explain how the matter could be disintegrated in a manner that the planet retained over 99 percent of the entire angular force in their orbit while the sun ended up with over 99.8 percent of the entire mass of the planetary system. There are other theories relating to the solar system. For example, the Chamberlin-Moulton theory proposed that materials from an exploding sun led to the formation planets. On the other hand, the star-Sun collusion model suggests that a gigantic star collided with the Sun and resulted in the formation of the planetary systems (Kasting 3). However, the solar nebula theory is currently the most recognized model that explains the manner in which planetary systems are formed. This model suggests that planets were created from dust particles and hydrogen gas. These components were by-products of previous cycles of stellar progression. The intricate interstellar shock waves processes caused the hydrogen gas to subside. As a result, the dust particles and hydrogen crumpled into a massive proto-planetary disk resembling a pancake. The bottom-up process is believed to have taken place within the disk planes. In addition, fusions and collision continued via several phases typified by qualitative disparities in each particle interaction. In other words, the primeval dust elements collided and combined on a continuous basis leading to the formation of rocks (approximately 10 meters in size). These rocks then proceeded to collide and developed into mini-planets (approximately 10km in size) after thousands of years (Kasting 3). The gravitational force caused the mini-planets to develop further into rock-strewn terrestrial planets (such as Mars and Earth). The int erior formations of the terrestrial planets were characterized by the chemical and physical delineation. In addition, the spherical outline of these planets was manipulated by their respective gravitational forces. The gaseous giant planets (i.e. Saturn and Jupiter) formed far away from the parent star. This happened because their moderately small cores quickly amassed the hydrogen gas that emanated from the flattening disk. If the process of planetary formation takes place in a systematic way, the ensuing planets will emerge in spherical trajectories and their orbital paths will be parallel to the spinning axis of the parent star.Advertising Looking for essay on astronomy? Let's see if we can help you! Get your first paper with 15% OFF Learn More In addition, their trajectories will be perpendicular to their rotation axes. In general, the gigantic planets will form far away from the parent star where additional disk matter is present for accumulation. It appears that the broad characteristics of our solar system emerged from the process described above. Scores of scientists believe that the snowline played a significant role in the formation of the planetary systems. It is an established fact that water turns into ice when the temperature falls below 180K. It appears that the snowline in the primordial solar nebular declined by approximately three times the distance between the sun and the Earth. There is a basis for this assertion since the C-class (water-rich) asteroids are principally located on the exterior part of the asteroid belt (Havel et al., 4). The Structural Design of the Planetary System The solar system is organized in an extremely intricate manner. The overall picture of the Sun, a limitless number of comets, the eight planets and their respective moons are simply astonishing. Their isotopic and chemical compositions, age, density and mass depict an elaborate record of primordial development and successive evolutions manipulated by gravitational force and moulded by the phenomenon of quality. According to the radiogenic experiments on meteorites and seismological studies, the solar system is believed to be approximately 4.5 billion years old. It is believed that the solar system was formed from the disintegrating dusts particles and hydrogen gas that came into existence around this period. Some scientists also believe that the eight planets were created from the systematic synthesis of protoplanets, planetesimals and rocks. Mars, Earth, Venus, and Mercury (terresial planets) formed adjacent to the Sun since there was a limited amount of disk particles (Kasting 3). Scientists have made some major breakthroughs relating to the origin and characteristics of exoplanets. These discoveries hav e been made possible because previous theories relating to the formation of the solar system laid the basis for comprehending the composition and dynamics of the solar system. However, these theories have undergone substantial adjustments in order to facilitate better understanding of our marvellous solar system. The current ground and space exploration missions are expected to new discoveries and augment the existing knowledge about the solar system. Havel, Mathew, Guillot Tristan, Valencia Diana and Crida Aurellen. The multiple planets transiting Kepler-9: Inferring stellar properties and planetary compositions. Cambridge, MA: MIT, 2011. Web. Kasting, James. â€Å"Habitable Planets: What Are We Learning from Kepler and Ground Based Searches?† Astrobiology 11.4. (2011):1-5. Web. Ormel, Cris and Kobayashi Hiroshi. Understanding How Planets Become Massive: Description and Validation of a New Toy Model. Berkeley, CA: University of California, 2011. Web. Salmon, William, Lovis Christophe, Queloz Didier and Segransan Damien. HD 5388b is a 69Mjup companion instead of a planet. Switzerland: University of Geneva, 2011. Web.