Neutron star

There are three main types of galaxies: irregular galaxies with no defined shape, elliptical galaxies that are flattened balls containing only old stars, and spiral galaxies with a central bulge and rotating disk containing gas, dust, and younger stars. Stars form within giant clouds of gas and dust called nebulae, and their lifetime depends on their mass - smaller stars live much longer than larger ones. The universe contains these galaxies, nebulae, and stars, all bound together by gravity.

This document discusses how the spectral classification of stars can reveal information about their composition and temperature. It explains that stars are classified into seven main categories (O, B, A, F, G, K, M) based on their absorption spectra, with O being the hottest and M being the coolest. Each class is associated with a range of surface temperatures and colors. By analyzing a star's spectrum, astronomers can determine what chemical elements are present in its atmosphere and measure its temperature, allowing insights into its composition and properties.

There are different life cycle stages for stars depending on their original mass. Low mass stars progress through the stages of nebula, main sequence, red giant, planetary nebula, white dwarf, and black dwarf. High mass stars go through nebula, main sequence, red supergiant, supernova, and either become a neutron star or black hole. The main sequence stage can last billions of years for low mass stars but only millions for high mass stars.

There are four main types of galaxies: elliptical, spiral, barred spiral, and irregular. The Milky Way is a giant barred spiral galaxy containing 200 billion stars. Galaxies range in size from thousands to trillions of stars. The Milky Way is approximately 10,000 light years in diameter and contains a supermassive black hole at its center.

Brief introduction on the topics of nuclear science on behalves of GSFC university. Umang Jagani

Contents The Big Bang Theory The Big Bang Phase Expanding Universe Testing Big Bang Model Dark matter & Dark energy Evidence of dark matter After time period of Big Bang Life cycle of star

Dark matter makes up 73% of the universe and is composed of unknown particles that do not emit or absorb light but have gravitational effects. Dark energy is 23% and is a repulsive force that is driving the expansion of the universe. Both dark matter and dark energy were hypothesized to explain inconsistencies in cosmological theories and observations of the structure and acceleration of the expanding universe.

Dark matter and dark energy make up 95% of the universe. Dark matter is an undetected form of matter that exerts gravitational pull but does not emit or interact with light. Its existence is inferred from its gravitational effects, such as the rotation speeds of galaxies. Dark energy is driving the accelerating expansion of the universe according to Hubble's law, contradicting the expected eventual gravitational collapse. While their effects can be observed, the true nature of dark matter and dark energy remain mysterious, as they have not been directly detected, and may hold potential future applications in spacecraft propulsion if their properties can be better understood.

This document discusses exoplanets and the search for extraterrestrial life. It describes how over 1800 exoplanets have been discovered orbiting stars other than the sun. It explains several methods used to detect exoplanets, including direct imaging, the transit method, astrometry, and radial velocity. It also discusses characteristics of potentially habitable exoplanets and provides details about Gliese 667 Cc, one of the most Earth-like exoplanets discovered. The document then reviews the history of exoplanet detection and outlines some of the earliest projects in the search for extraterrestrial intelligence, such as Projects Ozma and Phoenix.

Stars are born from clouds of gas and dust called nebulas. As the gas spins faster under gravity, it heats up and forms a protostar. Nuclear fusion then occurs, turning the protostar into a main sequence star that shines for millions of years by fusing hydrogen into helium. Eventually the hydrogen runs out, causing the star to expand into a red giant. From there, less massive stars will blow off their outer layers and collapse into white dwarfs, while more massive stars will explode in supernovas and collapse into neutron stars or black holes.

The document discusses the composition and structure of the universe, focusing on dark matter and dark energy. It explains that dark matter makes up 84.5% of the total matter in the universe and was first discovered in 1933, though its nature remains unknown. Theories suggest dark matter could be composed of supersymmetric particles or exist in a "hidden valley." Additionally, dark energy is thought to make up 70% of the universe and acts as a repulsive force associated with the vacuum of space.

This presentation is prepared in soran university by 3 chemical engineering students second stage in 2017