ASTRONOMICAL MYSTERIES

 

ASTRONOMICAL MYSTERIES

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1.   Could a Distant, Dark Body End Life on Earth?

If a nearby star went supernova, a gamma ray burst erupted nearby, or a black hole or a stream of anti matter somehow wandered into our neighborhood, it could spell disaster. While astronomers say those events are unlikely, another dark distant interloper could create havoc on earth by its mere presence. A number of astronomers suggest the Sun may have a hidden, dark companion that periodically sends comets sunward, raining them down on the inner solar system. Although we live in relative quite in cosmos danger lurks in space even with an invisible dark object.

2.   Is Jupiter a failed star?

 It would need to be about 75 times its current mass to ignite nuclear fusion in its core and become a star.  Jupiter as the largest planet in the solar system long before any spacecraft provided detailed exploration. The planet’s mammoth size — 88,846 miles (142,984 kilometers) at the equator — holds 2.5 times the mass of all the other planets combined. This makes Jupiter the most dominant body in the solar system after the Sun. The planet’s volume is so great that 1,321 Earths could fit inside it.

3.   Why Does Antimatter Exist?

 Shortly after the Big Bang, the cosmos was awash in particles. Not all of them were normal particles of matter, however. Corresponding with each type of particle is an antiparticle with the same mass and spin. The nature of our universe results from the fact that matter exists in slightly more quantity than antimatter. The difference is slight, however: For every billion particles of antimatter, there must have been a billion and one particles of matter in the early universe. Everything that exists — galaxies, stars, planets, trees, people — owes its existence to the slight surplus of matter.

    Anywhere high-energy collisions take place, antimatter is sure to be there. The powerful black hole in the center of the Milky Way produces an antimatter jet. The boundary where the antimatter collides with normal matter produces gamma rays.Antiparticles get made where the temperature is extremely high — for example, the event horizon of a black hole. Should we ever get to the point of traveling deep into space, hazards from antimatter, which annihilates matter when the two collide — would pose a real and somewhat unpredictable hazard.

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5.   What Creates Gravitational Waves?

 1916, Albert Einstein revolutionized our understanding of the universe when he published his general theory of relativity. In it, the German-born physicist described the complex relationship between the fabric of space-time and the mass of celestial bodies. Space-time is the combination of three spatial directions (height, width, and depth) with the time dimension.

The easiest way to interpret gravitational interactions, Einstein said, is to think of the space-time continuum as a stretchable material that bends as massive objects “sit” inside it. While this two-dimensional analogy does not represent what is happening in four-dimensional space-time, it serves as a capable model. M assive objects also cause another effect in the fabric of space-time. Just as a boat creates waves on a lake as it slices forward through the water, stars and other bodies in the universe create ripples in the fabric of space-time as they move. Astronomers call these ripples gravitational waves.

6.Where Do Cosmic Rays Come From?

   Physicists initially believed cosmic rays were gamma rays, high-energy radiation produced by radioactive decay. During the 1930s, however, experiments revealed that cosmic rays are mostly charged particles. In 1937, French physicist Pierre Auger (1899–1993) found that extensive particle showers (called air showers) occur when cosmic rays collide with particles high in the atmosphere, producing a cascade of electrons, positrons, photons, muons (particles similar to electrons but 200 times as massive), and other particles that reach Earth’s surface.

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7.What Happens When Black Holes Collide?

  It turns out a funny thing happens when black holes collide. They spiral toward each other and merge into a single entity. In some cases, a gravitational “slingshot” effect then violently whips them outside their host galaxies into intergalactic space. The ejection mechanism results from a byproduct of the merger: gravitational waves. The gravitational waves can actually kick the merged black hole far away from the site of its merger. In 2017, astronomers found compelling evidence of such a mechanism when they used Hubble to image quasar 3C 186. Observations of the offset quasar suggested that it was jettisoned from the core of its galaxy by gravitational waves produced by the merger of two supermassive black holes.

8.  After all, some 200 to 400 billion stars inhabit our galaxy, and astronomers estimate at least 125 billion other galaxies exist. That’s one heck of a number of stars in the universe — at least 25,000 billion billion. Looking at the nebular hypothesis, which describes how the solar system formed, it seems clear most stars would form planets as their protogenitor clouds collapsed. Yet, due to the immense distances, seeing other planetary systems remained a supreme challenge for astronomers until the past two decades.W ith the number of exoplanets growing week by week, researchers plan new and ambitious projects to expand the number of discoveries dramatically. Before Kepler, most exoplanets found were large “hot Jupiters.” The satellite, though, found hoards of smaller worlds and even spied a few possible Earth cousins. Current and future missions such as the Transiting Exoplanet Survey Satellite (TESS), the CHaracterising ExOPlanet Satellite (CHEOPS), and the Planetary Transits and Oscillations of stars (PLATO) will use the transit method to further expand the number of exoplanet discoveries. TESS, for example, will soon look across the entire sky to find all exoplanets around dim red stars within a few hundred light-years from Earth, as well as give astronomers targets for future missions that will search for gases produced by life, like methane and carbon dioxide.

9. Why Did Mars Dry Out?

  Years ago, astronomers detected signs of Mars’ watery past. Early evidence came from imaging large numbers of winding channels on the Red Planet.These images suggest abundant liquids of some type flowed on the planet at some point in its history. In 1972, the Mariner 9 spacecraft orbited Mars and took photos of what appear to be dry riverbeds scattered over the planet’s surface. T he clear implication is that Mars had a watery past and, for some reason, dried out, but not completely. Using images from the Mars Global Surveyor satellite, planetary scientists Devon Burr, Alfred McEwen, and colleagues looked carefully at Marte Vallis, a river channel that extends from Elysium Planitia into Amazonis Planitia. The flows would have to be significant to leave surface features because the temperatures and pressures on Mars’ surface today mean water quickly evaporates once it reaches the surface.  The climatic change may have shifted the planet to a less hospitable place. Moreover, Mars cooled following this period of volcanism. During the cooling, astronomers believe Mars’ magnetic field dissipated because the planet’s molten iron core solidified.

10.Is Water Necessary for Life?

  This works for planetary-exploration missions and for extrasolar-planet telescopes like Kepler. For many years, planetary scientists and biologists have held fast to one maxim: Water is essential for life. Great interest focuses on the possibility of extraterrestrial life, even if it’s merely microbial. So, follow the water to find where the big planetary-exploration dollars will be spent. L ife in the universe, astronomers and biologists now admit, could be based on completely different chemical systems than ours. The first thing to do is to define what we mean by “life.” By definition, living things have several properties that separate them from rocks and dirt. Living things on Earth are arranged into cells. They are also highly organized, on different levels and with different tasks. They take in energy from the environment and excrete waste products. They exhibit homeostasis, stable internal conditions that are required to stay alive. They grow and change, showing differentiation and mutation. They also reproduce, passing genetic material to their descendants. Anything in the universe that exhibits these characteristics would be considered a living being. If liquids other than water might help create and sustain life, which ones might they be? Water does have an amazing number of properties that help support life. But could another fluid — ammonia, methane, formamide, or sulfuric acid — create a place where exotic life forms could flourish?