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Type of Dwarf A star is a giant ball of extremely hot gas (plasma), sustained by nuclear fusion which turns hydrogen into helium. All this energy produces heat, light and bigger chemical elements. A star emits electromagnetic radiation that moves away from the star as light. The large mass of a star holds it together. Old stars change helium into other elements like carbon and oxygen. Yellow dwarfs - main-sequence stars like our own Sun, Alpha Centauri A, Tau Ceti, etc, typically about 80 - 100% of the size of the Sun, and actually more white than yellow. They are also known as G V stars for their spectral type G and luminosity class V. White stars - bright, main-sequence  stars  with  masses from 1.4 to 2.1 times the mass of the Sun and surface temperatures between 7,600°C and 10,000°C, such as Sirius A and Vega. Red giants - luminous giant stars of low or intermediate mass (usually between 0.5 and 10 solar masses) in a late phase of stellar evolution, such as Aldebera

What is Supernova Explosion? 💥 A supernova is an explosion of a massive supergiant star. It may shine with the brightness of 10 billion suns! The total energy output may be 1044 joules, as much as the total output of the sun during its 10 billion year lifetime. A supernova discovered by an international group of astronomers including Carnegie's Tom Holoien and Maria Drout, and led by University of Hawaii's Ben Shappee, provides an unprecedented look at the first moments of a violent stellar explosion. The light from the explosion's first hours showed an unexpected pattern, which Carnegie's Anthony Piro analyzed to reveal that the genesis of these phenomena is even more mysterious than previously thought. Astronomers have long tried to get detailed data at the initial moments of these explosions, with the hope of figuring out how these phenomena are triggered. This finally happened in February of this year with the discovery of a Type Ia supernova called ASA

The Big Bang Theory The Big Bang Theory is the leading explanation about how the universe began. At its simplest, it says the universe as we know it started with a small singularity, then inflated over the next 13.8 billion years to the cosmos that we know today. Georges Lemaitre had proposed a model for origin of the universe which became the Big Bang theory. The Big Bang theory explains the origin of universe, with the key idea that the universe is expanding. In the past, the universe was denser and hotter. All of space was contained in a single point, which is considered the inception of the universe. After the initial expansion, the universe freezes that allowed the creation of subatomic particles, consisting of protons, neutrons, and electrons. The majority of atoms formed were hydrogen, along with helium and traces of lithium. Huge clouds of these primal elements later fused through gravity to form stars and galaxies. The massive elements were synthesized either w

How do we know there are Billions of Galaxies? Our universe contains at least two trillion galaxies – 10 times more than we thought. Astronomers led by Christopher Conselice at the University of Nottingham in the UK converted “pencil beam” images of deep space stretching some 13 billion light-years into 3-D maps, allowing them to calculate the density of galaxies in that volume. This latest analysis uses mathematical models to estimate the number of both visible and hidden galaxies in snapshots like Hubble's famous Deep Field image. Using this method, Christopher Conselice, who studies galaxy formation at the University of Nottingham, and his team came up with a surprising conclusion: The models suggest that only about ten percent of galaxies in the universe are observable from Earth. That means our current technology misses about 90 percent of what’s out there, including trillions of galaxies, each with tens or hundreds of billions of stars. In the next

How many types of galaxies are there in the Universe?   Edwin Hubble divided the galaxies into three basic groups: ellipticals, spirals, and irregulars. The ellipticals are smooth and round or elliptical, the spirals are flat with a spiral pattern in their disk, and the irregulars have stars and gas in random patches.  Most galaxies are small and faint so only the luminous galaxies are seen at great distances. These spectacular galaxies tend to be either the elliptical or spiral type, so they are the ones often displayed in astronomy textbooks. Sprial Galaxy 15 percent of galaxies are spirals, flat galaxies with a central light concentration that show spiral arms in an outer disk. The central regions of spiral galaxies appear reddish and are composed of older Population II stars, such as those in the halo of the Milky Way Galaxy. Spiral galaxies range from intermediate to large galaxies, with masses in the range of 10 9 to 10 12 solar masses, diameters 6 kpc to 100 kpc

Several Techniques to Measure the Vast Distance Astronomers have developed several techniques to indirectly measure the vast distances between Earth and the stars and galaxies. In many cases, these methods are light year, parsec and astronomical unit. Astronomical Unit (A.U.) An astronomical unit (A.U.) is the average distance between the Earth and the Sun, which is about 93 million miles or 150 million kilometers. Astronomical units are usually used to measure distances within our solar system. For example, the planet Mercury is about 1/3 of an A.U. from the Sun, while the farthest planet, Pluto, is about 40 A.U. from the Sun (thats 40 times as far away from the Sun as the Earth is). 1 AU = 1.496 × 108 km = 93 million miles Light-Year (ly) Most objects in space are so far away, that using a relatively small unit of distance, such as an astronomical unit, is not practical. Instead, astronomers measure distances to objects which are outside our solar system in

Our Neighbor Galaxy: Andromeda Galaxy The Andromeda Galaxy was an inhabited galaxy located in the universe within relative proximity to the Milky Way. Andromeda had two satellite galaxies. An image depicting the Andromeda Galaxy was scanned by the Talosians as they reviewed the library computer files on board USS Enterprise in 2254. (TOS-R: "The Cage") An older image of the Andromeda Galaxy appeared in the original "The Cage". This image was replaced for the remastered episode. This galaxy was located in the Andromedaconstellation. In the real world, the Andromeda Galaxy is 2,537,000 light-years from Earth. The Messier Catalog number for this galaxy was M31. Both the Andromeda and the Milky Way were located within the Local Group of galaxies. The distance between the Andromeda Galaxy and the Milky Way Galaxy was either about one million light years (Star Trek Encyclopedia (4th ed., vol. 1, p. 28)) or about 2 million light years. The Andromeda

Main cause of Global Warming First among them, there's no longer any question that rising temperatures and increasingly chaotic weather are the work of humanity. There's a 99.9999% chance that humans are the cause of global warming, a February study reported. That means we've reached the "gold standard" for certainty, a statistical measure typically used in particle physics. The mechanism is well understood and has been for decades. Humans burn fossil fuels such as oil, coal and gas, which release carbon dioxide (CO2), methane and other gases into the Earth's atmosphere and oceans. CO2 is the greenhouse gas that's most responsible for warming. Report past 5 year The past five years have been the five warmest since record-keeping began in the late 1800s. The Earth has experienced 42 straight years (since 1977) with an above-average global temperature, according to the National Oceanic and Atmospheric Administration. Based on five separate d

Spacesuits Spacesuits allow astronauts to work outside a spacecraft in orbit, on the moon or on another planet. A spacesuit is much more than a set of clothes astronauts wear on spacewalks. A fully equipped spacesuit is really a one-person spacecraft. The formal name for the spacesuit used on the space shuttle and International Space Station is the Extravehicular Mobility Unit, or EMU. "Extravehicular" means outside of the vehicle or spacecraft. "Mobility" means that the astronaut can move around in the suit. The spacesuit protects the astronaut from the dangers of being outside in space. What Are the Parts of a Spacesuit? The spacesuit consists of several pieces. The Hard Upper Torso covers the astronaut's chest. The arm assembly covers the arms and connects to the gloves. The helmet and Extravehicular Visor Assembly are designed to protect the astronaut's head while still allowing him or her to see as much as possible. The Lower Torso Assemb

The Hubble Space Telescope The Hubble Space Telescope is a collaboration between ESA and NASA. It's a long-term, space-based observatory. The observations are carried out in visible, infrared and ultraviolet light. In many ways Hubble has revolutionised modern astronomy, by not only being an efficient tool for making new discoveries, but also by driving astronomical research in general. History When Galileo first turned a spyglass to the heavens in 1610, he had trouble making out the rings of Saturn that are visible in inexpensive telescopes today. Advances in optics improved scientists' views of the planets, stars, and distant galaxies, but Earth's atmosphere still blocked much of the light for observers on the ground. Larger telescopes were (and still are) placed on high mountains, where thinner atmospheres allow clearer pictures. More About The Hubble is a joint project between NASA and the European Space Agency. Here are some basic facts about the t