This may be due to the intense gravity of these planets. They may have more of a tendency to capture wandering asteroids and planetoids then the terrestrial planets.
It is believed that the ring systems may have formed from old moons that were pulverized by the tidal forces of the planets' gravity. Dwarf Planets - Dwarf planets are bodies in orbit around a star that are neither planets nor natural satellites. They are massive enough for their shape to be in hydrostatic equilibrium under their own gravity, but they have not cleared the neighborhood around their orbits.
Pluto is a prime example of a dwarf planet in out own solar system. Four new dwarf planets have been discovered beyond the orbit of Pluto, and astronomers believe there could be hundreds more. These bodies are so far away that they are difficut to see even with the most powerful telescopes.
Many large telescopes are under construction that may be able to help identify new dwarf planet candidates. Planet formation is still somewhat of a mystery, but most astronomers believe they understand the basic process.
The best explanation accepted today is known as the solar nebula hypothesis. In this process, stars are formed from giant clouds of gas and dust known as nebulae. Gravity causes the matter in the nebula to coalesce, or come together. These strong gravitational forces soon causes the central part of the nebula to collapse and form a star. The remaining gas and dust forms a flat, rotating ring around the new star.
Eventually the gravity of the star begins to pull matter towards it. Small whirlpools of spinning matter form within this disk. Gravity causes these whirlpools to aggregate into small masses known as planetesimals. These planetesimals continue growing, pulling in the matter around them. Gravity soon pulls them into a spherical shape. These small spheres may collide and merge with others as they grow in size and become what is known as a protoplanet.
Sometimes, a smaller sphere of matter may become captured by a larger one and enter into an orbit, creating a moon. Over time, gravity causes the heavier elements in the protoplanets to separate from the lighter ones in a process called uniformitarianism.
This forms the planet's metal core, rocky crust, and usually an atmosphere composed of gas. As the star and planets continue to grow, the dust and gas of the nebula begins to thin. Smaller chunks of condensed matter is left over in the outer regions of the disk. These form the Kuiper belt of planetoids and the Oort cloud of comets. Eventually the solar wind from the star will blow away the excess gas and dust.
A new solar system has been born. The process is slow and takes millions of years. Many stars have been observed to have flat disks of matter around them. These could very well be new solar systems in the making. Astronomers have theorized about planets outside our Solar System, also known as extrasolar planets , since the midth century. Some of the first evidence of an extrasolar planet was seen in , when Barnard's star was noticed to have an unusually large proper motion.
In the past few decades, many other potential planet candidates have been identified but not confirmed. Celestial Objects to Observe. If skies are clear this weekend, you'll see the full Moon. And not just any old full Moon, but the Blue Moon. By: Diana Hannikainen August 19, The recurrent nova RS Ophiuchi just went into outburst — its first burst in 15 years — and it's bright enough to see with the naked eye.
By: Bob King August 9, For many, smoke from wildfires has transformed summer nights, blotting out stars and familiar deep-sky sights. But through it all double stars keep on shining.
By: Bob King July 28, Deep Sky. Take some time to explore the overlooked masterpiece of Messier By: Josh Urban July 21, Variable Stars. M7 in Scorpius is one of the brightest, most beautiful open clusters in the sky. It's also "home" to a half-dozen other delectable deep-sky sights.
By: Bob King July 14, By: Jamie Carter June 21, Lyra, the Lyre, offers a wonderful assortment of double stars and deep-sky objects to keep you up at night. Break out your binoculars and telescope and join me for a summertime ramble. By: Bob King June 16, This applies, in particular, to the designation "planets". The word "planet" originally described "wanderers" that were known only as moving lights in the sky.
Recent discoveries lead us to create a new definition, which we can make using currently available scientific information. The IAU therefore resolves that planets and other bodies, except satellites, in our Solar System be defined into three distinct categories in the following way:.
Debate—and Discoveries—Continue. Astronomers and planetary scientists did not unanimously agree with these definitions. To some it appeared that the classification scheme was designed to limit the number of planets; to others it was incomplete and the terms unclear.
Some astronomers argued that location context is important, especially in understanding the formation and evolution of the solar system. One idea is to simply define a planet as a natural object in space that is massive enough for gravity to make it approximately spherical. But some scientists objected that this simple definition does not take into account what degree of measurable roundness is needed for an object to be considered round.
In fact, it is often difficult to accurately determine the shapes of some distant objects. Others argue that where an object is located or what it is made of do matter and there should not be a concern with dynamics; that is, whether or not an object sweeps up or scatters away its immediate neighbors, or holds them in stable orbits.
The lively planethood debate continues. As our knowledge deepens and expands, the more complex and intriguing the universe appears. Researchers have found hundreds of extrasolar planets, or exoplanets, that reside outside our solar system; there may be billions of exoplanets in the Milky Way Galaxy alone, and some may be habitable have conditions favorable to life. Whether our definitions of planet can be applied to these newly found objects remains to be seen.
What is a Planet? Introduction This seemingly simple question doesn't have a simple answer. It says a planet must do three things: It must orbit a star in our cosmic neighborhood, the Sun. It must be big enough to have enough gravity to force it into a spherical shape. It must be big enough that its gravity cleared away any other objects of a similar size near its orbit around the Sun.
The Scientific Process The Scientific Process Science is a dynamic process of questioning, hypothesizing, discovering, and changing previous ideas based on what is learned. An Evolving Definition An Evolving Definition Defining the term planet is important, because such definitions reflect our understanding of the origins, architecture, and evolution of our solar system.
The IAU therefore resolves that planets and other bodies, except satellites, in our Solar System be defined into three distinct categories in the following way: A planet is a celestial body that a is in orbit around the Sun, b has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium nearly round shape, and c has cleared the neighbourhood around its orbit.
A "dwarf planet" is a celestial body that a is in orbit around the Sun, b has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium nearly round shape, c has not cleared the neighbourhood around its orbit, and d is not a satellite.
All other objects,except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies". Debate—and Discoveries—Continue Debate—and Discoveries—Continue Astronomers and planetary scientists did not unanimously agree with these definitions. Full Moon Guide: October - November
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