About the gravitational and space exploration Essay Example

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Gravitational lensing

(Eistein ;1936). Gravitational lensing is a phenomenon where there is bending of light rays from a distance object such as background galaxy. The bending of the light rays is may be caused by cluster galaxies which are between the background galaxy and the observer. The phenomenon of gravitational lensing a typical example of predictions of general theory of relativity by Albert Eistein

» SBS 0957+561.Twin QSO. For cases involving complex lensing mass like for the case of galaxy groups and clusters a spherical distortion of space-time is not experienced but source will tend to resemble partial arcs seen around the lens. There is a likelihood of the observer seeing multiple distorted images associated with the same source with the shape and number of the images being dependant on the positioning of the observer, lens and source and also the lensing object’s gravitational well shape. It was Fritz Zwicky who posited in 1937 that the effect had the capability of allowing galaxy clusters to act like gravitational lenses; but the confirmation of this was until 1979 where there was observation of what is referred to as «Refsdal, S., & Surdej, J., 1994),Orest Chwolson and Frantisek have received some credit for being the first to discuss the phonomenon on print, gravitational lensing is majorly attributed to Albert Einstein for publishing an outstanding article on this subject in 1936. In literature the gravitational lensing phonomenon is usually referred to as Einstein ring as Chwolson did not have an interest with the flux or radius of ring like image (

Optical length

Optical lenses are important devices which find application in many applications where there is need for light rays to be manipulated. The lenses work by refracting the light waves in a certain way depending of the way the lenses have been constructed. The optical lens refracts the light to the focal point. The optical lenses which can be seen to be close to gravitational lenses are the positive lenses as in both cases a real object that can be projected on the screen can be created. The actual image created by the positive lens will be dependant on the object position relative the object. As can be observed in figure 1 there are three rays which are important in locating the image created. The type of image created by a positive lens is dependant of the position of the object relative to the lens. For an object which is beyond 2F a real image will be created between F and 2F. The object created will be small than the actual object but not distorted as seen in figure 2. From figure 3 it is observed that when the object is between 2F and F a real image is created which is bigger than the object and the image is beyond 2F. For the case where the object is at 2F the image is real, at 2F and is not magnified as can be seen in figure 4. On the other hand if the object is between F and the lens the image created is virtual, upright and magnified as can be seen in figure 5. The optical lenses can be used in magnification of small object like the case of the hand lens. They can also be used in combination to achieve higher magnification like the case of the microscope (The Physics classroom, 2013).

about the gravitational and space exploration

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Comparing and contrasting of gravitational lensing and optical lens

. In gravitational lensing maximum bending of the rays is experienced at areas nearest to the centre of object while least bending of rays is experienced in the areas that are furthest from the centres; this is the opposite for the case of optical lenses. In gravitational lensing the images that are created are distorted unlike in the case of the optical lenses as can be seen in figure 6. In optical lenses the light rays passes through the lenses unlike the gravitational lensing where the light is passing in the neighborhood of the “lens”. Blandford, R.D., &Narayan, R. ,1992) that the deflection of light by galaxies was not only an additional test relativity but also brings about magnification of distant galaxies that would be impossible to detect and also makes it possible to determine the masses of the galaxyBartelmann, M., & Narayan, R., 1995)In gravitational lensing the lens effect is obtained from massive bodies in the sky which are far away from the observer in contrast to the case of the optical lens where the lens are close to the observer and the lenses are also of small size. In optical lenses the magnification of objects is only possible when the objects are very close to the lens ( a distance of less than F from the lens) but in gravitational lenses there is magnification of objects which are very far from the gravitational lenses. This is manifested by (

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Bartelmann, M., & Narayan, R. (1995). Gravitational Lensing and theMass Distribution of Clusters, in: Dark Matter AIP Conf. Proc. 336, eds. S.S. Holt & C.L. Bennett (New York: AIP Press)

Blandford, R.D., &Narayan, R. (1992). Cosmological Applications of Gravitational Lensing, Ann. Rev. Astr. Ap., 30, 311

Fort, B., & Mellier, Y. (1994). Arc(let)s in Clusters of Galaxies, Astr. Ap. Rev., 5, 239

Keeton II, C.R. & Kochanek, C.S. (1996). Summary of Data on Secure Multiply-Imaged Systems, in: Cosmological Applications of Gravitational Lensing, IAU Symp. 173, eds.C.S. Kochanek & J.N. Hewitt

Paczy´nski, B. (1996). Gravitational Microlensing in the Local Group, Ann. Rev. Astr. Ap., 34, 419

Roulet, E., & Mollerach, (1997). Microlensing, Physics Reports, 279, 67

Refsdal, S., & Surdej, J. (1994), Gravitational Lenses, Rep. Progr. Phys., 57, 117

on 5th August 2013http://www.physicsclassroom.com/class/refrn/u14l5da.cfmThe Physic classroom. Converging Lenses — Ray Diagrams. Retrieved from

Trojan asteroids

and they lie at approximately 60° behind or 60° ahead of the host body (Connors, et al, 2011; Whiteley, R. J.; and Tholen, D.J. (1998).5L and 4LA trojan is defined as a small planet or a natural satellite also known as a moon. The natural satellite shares the same orbit with a larger planet or a lager natural satellite with no risk of collision of the bodies (Wright, 2011; Yoshida, F. et al 2005). The possibility of collision is eliminated because the minor planet orbits around one of the two trojan points which are also referred to as Lagrangian points of stability. In the diagram the two trojan points are marked

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The objects occupying these points are sometimes referred to as Lagrangian objects and also qualify as one type of co-orbital objects. When the bodies are in this arrangement, the big star and the natural satellite of smaller size orbit around their common barycenter which is a point in the space that mutual gravitational attraction of the two bodies balance out each other (Powell, D., 2007). The smaller natural satellite which is at one of the two trojan points is being acted upon by a combined gravitational force whose action is through the barycenter. Because of this arrangement the object is able to go around the barycenter with an orbital period same as that of the hosting planet making the arrangement to remain stable over time (Choi, 2011). The trojan asteroids orbits near one of the two Lagrangian points of stability of the host planet. According to the numerical calculation which have been made the orbital dynamics have given indication that Saturn and Uranus may not have primordial trojan asteroids.

Wright, A. (2011). «Planetary science: The Trojan is out there». Nature Physics
7 (8): 592.

Yoshida, F. et al (2005). «Size distribution of faint 4L Trojan asteroids». The Astronomical journal
130 (6): 2900–11. Bibcode:2005AJ….130.2900Y. doi:10.1086/497571

Connors, M. et al ( 2011). «Earth’s Trojan asteroid». Nature
475 (7357): 481–483. Bibcode:2011Natur.475..481C. doi:10.1038/nature10233. PMID 21796207. Retrieved 2011-07-27. 

Whiteley, R. J.; and Tholen, D.J. (1998) «A CCD Search for Lagrangian Asteroids of the Earth–Sun System», Icarus 136:1, November:154–167

. Space.com. «Neptune May Have Thousands of Escorts»Powell, D. ( 2007).

Choi, Q. (2011). «First Asteroid Companion of Earth Discovered at Last». Space.com.