Hubble Studies Giant Gas Bubbles Near our Galaxys Core

Hubble Studies Giant Gas Bubbles Near our Galaxy's Core Its an ancient galactic mystery with a modern explanation: two million years ago, something happened at the center of our Milky Way galaxy. Something energetic. Something that sent two huge bubbles of gas billowing out to space. Today, they stretch out across more than 30,000 light-years of space, extending above and below the plane of the Milky Way.  No one was around to see it then at least no humans on Earth. Our earliest primate  ancestors were just learning to walk upright, and astronomy was not likely on their list of activities. So, this major explosion went unnoticed. Yet, it was a titanic event, driving gases and other material outward at two million miles per hour, didnt affect our plane then and it wont likely affect us in the future. However, it does show us what happens when a massive explosion occurs some 25,000 light-years away from our planet. Hubble Sleuths the Cause of the Explosion Astronomers used  Hubble Space Telescope  to look through one lobe of the bubbles toward a very distant quasar. Thats a galaxy that is very bright in  both visible and other wavelengths of light. The quasars passed through the bubbles of gas, which allowed Hubble to peer inside the  bubble to learn more about it- like  looking at a distant light shining through a fog bank.   The enormous structure illustrated in this image was discovered five years ago as a gamma-ray glow on the sky in the direction of the galactic center. The balloon-like features have since been observed in x-rays and radio waves. The Hubble Space Telescope presented a good way to measure the velocity and composition of the mystery lobes.  With the data from HST,  astronomers will work on calculating the mass of the material being blown out of our galaxy. That might also let them figure out just what happened to send all this gas billowing out of the galaxy in the first place. What Caused this Massive Galactic Explosion? The two most likely scenarios that explain these bipolar lobes are 1) a firestorm of star birth at the Milky Ways center or 2) the eruption of its supermassive black hole.   This isnt the first time that gaseous winds and streams of material have been seen coming from the centers of galaxies, but its the first time astronomers have detected evidence for them in our own galaxy.   The giant lobes are called Fermi Bubbles. They were initially spotted using NASAs Fermi Gamma-ray Space Telescope to track gamma-rays.  These emissions are a powerful clue that a violent event in the galaxys core aggressively launched energized gas into space. To provide more information about the outflows, Hubbles Cosmic Origins Spectrograph (COS) studied the ultraviolet light from a distant quasar that lies beyond the base of the northern bubble. Imprinted on that light as it travels through the lobe is information about the velocity, composition, and temperature of the expanding gas inside the bubble, which only COS can provide. The COS data show that the gas is rushing from the galactic center at roughly 3 million kilometers an hour (2 million miles an hour). of the gas at approximately 17,500 degrees Fahrenheit, which is much cooler than most of the 18-million-degree gas in the outflow. This cooler gas means that some interstellar gas could be getting caught up in the outflow.   COS observations also reveal that the clouds of gas contain the elements silicon, carbon, and aluminum.  These are produced inside stars.   Does this mean that star formation or star death is involved in the original event that formed the bubbles? Astronomers think that one possible cause for the outflows is a star-making frenzy near the galactic center. Eventually, those hot, young massive stars die in supernova explosions, which blow out gas. If a lot of them exploded at once, it might spur the formation of a huge gas bubble.   Another scenario has a star or a group of stars falling onto the Milky Ways supermassive black hole. When that happens, gas superheated by the black hole blasts deep into space and that could be what filled out the bubbles.   Those bubbles are short-lived compared to the age of our galaxy (which is more than 10 billion years old). Its possible that these arent the first bubbles to billow out from the core. It could have happened before.   Astronomers will continue to look at these bubbles using distant quasars as illuminators, so it might not be too long before we hear just what it was that caused a huge commotion at the heart of the Milky Way Galaxy.  They may well also be interested in studying smaller such bubbles that form as a result of supernova explosions and the actions of hot young stars. Such bubbles actually work to protect systems encased within. One example is the Local Interstellar Cloud, which encases the solar system today. In a few tens of thousands of years, the Sun and planets will move outside of it, exposing our system to radiation levels it hasnt experienced for a long time.

12 More Military Terms Used in Civilian Contexts

12 More Military Terms Used in Civilian Contexts 12 More Military Terms Used in Civilian Contexts 12 More Military Terms Used in Civilian Contexts By Mark Nichol Following up on a post about words that originally pertained (or in one sense pertain) to military units but have developed nonmilitary connotations based on that sense, here are additional terms referring to military individuals or groups that have civilian senses as well. 1. captain: ultimately from Latin caput (â€Å"head†), originally referring to the leader of a war party and later to a military officer in command of a set unit or a ship; later, applied in general to a leader or head of a group or team. 2. cavalry: from Italian cavaliere (â€Å"horseman†), a body of soldiers mounted on horses (and later those assigned to mechanized units); by extension, from the clichà © in movie westerns of a US cavalry unit coming to the rescue of the protagonists, used in references to one or more people who bring aid to others. 3. lieutenant: from Old French lieu tenant (â€Å"in place of†), originally, an officer who was deputy to a captain but later also a specific military rank; in civilian usage, a right-hand man or woman or a subordinate. 4. muster: from Latin monstrare (â€Å"to show†)- interestingly, akin to monster- referring to an assembly of military personnel or serving as a verb synonymous with assemble, but also pertains to any assembly, collection, or inventory or to a sample or specimen. 5. picket: from French piquer (â€Å"pierce†), a group of soldiers assigned to guard a camp, or the action of doing so; in civilian usage, a distinct meaning of â€Å"protesting during a demonstration or strike† or a reference to a sharp stake, such as one that is part of a picket fence. 6. rank-and-file: from Old English ranc (â€Å"strong†) and Latin filum (â€Å"cord† or â€Å"thread), the arrangement of military personnel in rows and columns; by extension, a reference to ordinary employees or members as opposed to those in leadership roles . 7. reserve: from Latin reservare (â€Å"keep back†), one or more units of soldiers kept more or less in readiness in case they are needed as reinforcements; in general usage, anything kept in stock or kept apart from a general issue or supply. 8. scout: from Latin auscultare (â€Å"heed,† â€Å"listen†), a person, sometimes a local civilian- or a group called a scouting party- sent to explore, observe, or search to obtain information about the enemy; in entertainment or sports, someone who observes prospective performers or recruits. 9. sergeant: from Latin serviens (â€Å"servant†), originally referred to a servant but later applied to an experienced common soldier who supervised others under command of a nobleman or knight; the term now denotes an experienced soldier or police officer holding the rank of sergeant or (in the military) a variation of the rank such as staff sergeant. 10. task force: from taxare (â€Å"tax†), a unit formed temporarily to achieve a specific objective; the sense in civilian usage is the same. 11. troops: from Old French trope (â€Å"band,† â€Å"company†), also the source of troupe, collectively refers to soldiers (in singular form the name of a specific military unit, not a designation for a single soldier); in general usage, an informal reference to a company’s employees or an organization’s members (as in â€Å"Round up the troops for a meeting†). 12. wingman: originally a term for a pilot who supports the leader of a flying formation, now also slang for someone who backs up a person who seeks to approach potential romantic or sexual partners. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Vocabulary category, check our popular posts, or choose a related post below:When to use "on" and when to use "in""Certified" and "Certificated"20 Ways to Laugh