ES 1010 Earth Science

Stars are the most recognized astronomical object in space and they represent the building blocks of galaxies. Stars distribute elements such as: carbon, nitrogen, and oxygen. A star develops from a cloud of hydrogen and helium, the dust clouds that are scattered throughout galaxies. An example of a dust cloud is the Orion Nebula. The gas and dust begin to collapse from its own gravitational pull. As the cloud collapses, the middle gets hotter. This is known as a prostar. A dense and hot core forms which begins to collect dust and gas. All this material may not end up as a part of the star but can become planets, asteroids, comets, or remain dust. A star about the size of our sun can up to 50 million years to mature. The smallest stars are

Geology is an overall study of planet Earth—“its composition, structure, process, and history” (Shipman, Todd, & Wilson 602). Geology also plays a role in the study of the Moon and other solar system objects is primarily the province of astronomy. “None of the remarkable scientific advances of the twentieth century revealed with certainty the composition and structure of the Earth’s interior” (603). Present ideas presently rest on indirect evidence provided by earthquake body waves, their speed and direction identifying the types of materials through which they move, meteorites whose composition is believed to be similar to the Earth’s, spacecraft measurements of gravity and magnetic variations, and laboratory

This problem wasn't solved until the 1920s, when Edwin Hubble devised the first method of extragalactic distance measurement. His technique relied on stars known as Cepheid variables, whose luminosities can be easily determined by measuring their rates of pulsation. Comparing this luminosity with the stars' observed brightness allowed Hubble to estimate the distance to Cepheid stars in such galaxies, affirming their extragalactic location.

It is easy to flip to the index of an astronomy textbook to discover that, say, the Sun lies 150 million kilometers away from Earth.  It is far more difficult (if not impossible), however, to picture this distance in the human mind.  In this exercise, we will learn to access the often unpalatable distances encountered in astronomy by simply scaling the huge distances to more recognizable, pedestrian numbers.  So long as every distance within the system of interest is scaled by the same factor, we retain the meaningful information about relative distances between objects.

Q.4) A star in a close binary that transforms into a black hole causes all outward pressures on a collapsing star to fail in stopping its inward motion. (DTU 10TH ED Page: 441)

Out of the four options, light-years measure the greatest distance. The distance in the other units would be too large. It is easier to read measurements when using a unit that can scale a larger area.

The Sun is one astronomical unit away so in actuality, it’s 0.00001581 light years away. Sirius looks smaller than the sun because it’s almost 9 light years away, which means it’s 92,919,000 or the astronomical units away. Sirius has a dwarf or twin star next to it, this star is called Sirius B. Sirius B was assumed to exist in 1844 but it wasn’t actually discovered until almost 18 years later!

A parallax is used to measure a star’s distance. During every 6 months’ astronomers look at a star and record it they then measure the distance it moved to find the actual distance from the sun.

But there is another theory too about this transformation. In this theory the transformation is a more gentle process. According to it the stars formed in a disk. Which is gradually moving to the center of a disk and producing a central pile-up of stars.

In the 1920’s Hubble determined that there were similar Cepheid stars in nearby galaxies like ones in our own Galaxy. With this discovery, he learned that they were faint and thus far away from Earth. He found a way to measure distance by finding common features that we already knew about in our own galaxy. Hubbles’ discoveries were not perfect since his tools and calibrations were not sophisticated, but his ideas helped to implement early forms of determining distance of objects in our Solar System.

Astronomers use Cepheid stars to measure distance. First, the period of a distant Cepheid is measured. The period is the length of time between brightness peaks. Next, they measure the peak luminosity of the star itself; this gives them the apparent brightness. Then, assuming that all Cepheids of the same period have the same absolute brightness, the distance is computed

Stage 8 is when the star starts to run out of fuel. It has spent close to 10 billion years burning hydrogen in its core and now it’s starting to run low and almost empty of the fuel it requires to keep burning. As the hydrogen starts to run low, helium levels start to increase in the higher temperature core as well as on the surface. However, the surface helium isn’t as noticeable because it doesn’t burn as high or fast as the inner core. But as the hydrogen completely runs out, the nuclear fusion subsides and a core of non-burning helium grows, forcing the burning of the star to head out of the inner core and up to the outer core. At this point, the radius of the star starts to grow rapidly because of the gas pressure and the core shrinks under the pressure of gravity.

The Nebula is the first stage which the star is born. The Nebula is actually a cloud of hydrogen gas and dust in space. There are a couple different types of

Mega parsec (Mpc) is a unit that consists of 1 million parsec, where 1 parsec is equal to 3.26 light years. Distance indicators are used to measure distances of objects brighter than Cepheid stars. Hubble’s Law is the relationship between the distances of galaxies; the further away the galaxy is the faster its moving. Spiral Galaxy is where there is a central hub surrounded by a disk of stars, gas and dust in a spiral pattern. Elliptical Galaxy is a round ball shape galaxy which consisting of almost a trillion stars in them. Irregular Galaxies are small galaxies that have no fixed shape. Barred Spiral Galaxy is a galaxy that has a nucleus which has a shape of a bar from which the spirals arms extend. Star Burst Galaxy is galaxies that are undergoing

Stars are made from an interstellar gas cloud. It was believed that in the process of forming a star, the cloud released material onto the interstellar disk in which the stars gradually accumulated it. However, because some stars seemed to have a drastic increase of brightness in a short amount of time, this idea had to be reconsidered. The stars that went through this process seemed to maintain their high luminosity for about 100 years. Astrophysicist Eduard Vorobyov suggested the idea that the material surrounding a forming star fragments off into clumps and is consumed by the star in a process that he describes as “cannibalism on astronomical scales.” Because these clumps are large, they release a large amount of energy when consumed