not_exactly_rocketscience

What exactly are black holes? A black hole is a region of space with a gravitational pull so powerful that nothing can escape from it, not even light. The visualization simulates the appearance of a black hole where infalling matter has collected into a thin, hot structure called an accretion disk. Credit: Event Horizon Telescope Collaboration How do black holes develop? A large star collapsing in on itself creates a region of space with a very high gravitational pull, which is how black holes are created. Artist's conception depicting the growth channels of black holes in the nearby and distant universe. In the nearby universe, smaller black holes grow by accretion while larger black holes grow by mergers. In the distant universe, the opposite is true. Credit: M. Weiss How large can black holes grow? Black holes can be as big as billions of times the mass of the Sun or just a few times it. Black holes are some of the most fascinating objects in space.  (Image credit: solarseven vi

Although stars are inanimate objects, we tend to describe their stages of evolution as if they were alive. Just like us, they are born, live, and then die. Of course, their lifetimes are much longer than ours and they can ‘live’ for billions of years. And during their lives, stars produce monumental amounts of energy through nuclear processes in their interior, giving them their characteristic shine. So let’s start at the beginning. Where do stars come from? A Giant Gas Cloud A star begins life as a giant cloud of gas which is generally an accumulation of dust, gas, and plasma. Stars form inside relatively dense concentrations of interstellar gas and dust known as molecular clouds. At these temperatures, gases become molecular meaning that atoms bind together. CO and H2 are the most common molecules in interstellar gas clouds. Pillars of Creation. An interstellar cloud of gas and dust in the Eagle Nebula,  known for its complexity and beauty. A Protostar Is a Baby Star A protostar look

Space is big! Science is cool! Let’s talk about it. WHAT IS A SUPERNOVA? Stars are kind of like people. They are born, live their entire lives, and then die. Except, that’s an oversimplification. Stars are giants. But they’re also giant chemical reactions. Just like a fire, though, stars will eventually burn through their fuel supply. The difference is that when a fire exhausts its fuel, it doesn’t blow up into something multiple of its original size, nor does it collapse back on itself to form super-dense matter. When a star “burns out,” many things can happen. But the main one is that the forces that balance out this giant object fall into an imbalance. Here’s how NASA explains it: “Massive stars burn huge amounts of nuclear fuel at their cores or centers. This produces tons of energy, so the center gets very hot. Heat generates pressure, and the pressure created by a star’s nuclear burning also keeps that star from collapsing. A star is in the balance between two opposite forces. Th

  WHAT IS A QUASAR? The word  quasar  stands for  quasi-stellar radio source . Quasars got that name because they looked starlike when astronomers first began to notice them in the late 1950s and early 60s. But quasars aren’t stars. Scientists now know they are young galaxies, located at vast distances from us, with their numbers increasing towards the edge of the visible universe. How can they be so far away and yet still visible? The answer is that quasars are extremely bright, up to 1,000 times brighter than our Milky Way galaxy. We know, therefore, that they’re highly  active , emitting staggering amounts of radiation across the entire  electromagnetic spectrum . Shining so brightly that they eclipse the ancient galaxies that contain them, quasars are distant objects powered by black holes a billion times as massive as our sun. These powerful dynamos have fascinated astronomers since their discovery half a century ago. In the 1930s, Karl Jansky, a physicist with Bell Telephone Labo

  TECTONIC PLATES The solid lithosphere is believed to be made up of several crustal plates or tectonic plates (which are sixteen to twenty great slabs of rock) floating on the part of the mantle called the asthenosphere . They move in response to convection currents in the upper mantle. Magma rises from the core and lower mantle towards the surface and spreads out at mid-oceanic ridges. The plates are hot at mid-oceanic ridges but over a period of a million years or so, as these plates moved apart and cooled, the colder plate descended at the trenches dragging the surface plate with it. The asthenosphere showed at a  subduction  boundary A crustal plate is an area of continental and oceanic crust along with the upper mantle. These plates have been in constant motion and over millions of years they have formed continents and ocean basins and their irregularities. The shape of the continents is believed to have evolved and changed over millions of years due to crustal plate movements. I

  FRAME OF REFERENCE Various physical phenomena, events, etc., require position and time coordinates to specify their complete description. Since nothing seems stationary in the universe, some arbitrary reference systems have to be defined with respect to which the position and the time coordinates for the event, etc., can be assigned. Such a system is called a 'frame of reference'. INERTIAL AND NON-INERTIAL REFERENCE FRAMES Newton's first law tells us that we can find a reference frame relative to which a body remains at rest or in uniform motion along a straight line when no net external force acts upon it. Such a reference frame is called an 'inertial reference frame'. Thus an inertial frame is one in which Newton's first law correctly describes the motion of a body not acted upon by a net force. Such frames are either at rest or moving with uniform velocity with respect to distant stars. Thus, they are unaccelerated and non-rotating. A reference frame attach

 PLANETS The word 'planet' originates from a Greek word meaning 'wanderer'. Planets are bodies that revolve around the sun, rotate on their own axes (plural of axis), do not have heat or light of their own and shine only because they reflect sunlight Planet Earth, as seen from the moon. Although the Apollo 11 team spent  only two and a half hours on the moon and went only 60 m from their landing capsule, they brought back information that has helped many years of subsequent research. Apart from the earth, seven other major planets revolve around the sun in their respective orbits. The eight planets in order of their distance from the sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Earth is the only planet known to support life.  The planets orbit the sun in the same direction; the closer they are to the sun, the faster they revolve. The inner planets (Mercury, Venus, Earth, Mars) have a shorter period of revolution. Modern science has revoluti