https://padlet.com/303994/ihfajn6voete Made with serendipity en-us 2018-01-09 21:43:50 UTC 2025-11-19 13:14:10 UTC hello@padlet.com 303994 https://padlet.com/303994/ihfajn6voete/wish/219994326 The universe was born with the Big Bang as an unimaginably hot, dense point. When the universe was just 10^-34 of a second or so old — that is, a hundredth of a billionth of a trillionth of a trillionth of a second in age — it experienced an incredible burst of expansion known as inflation, in which space itself expanded faster than the speed of light. During this period, the universe doubled in size at least 90 times, going from subatomic-sized to golf-ball-sized almost instantaneously.]]> 2018-01-09 22:01:06 UTC https://padlet.com/303994/ihfajn6voete/wish/219994326 303994 https://padlet.com/303994/ihfajn6voete/wish/219994897 The sun at the heart of our solar system is a yellow dwarf star, a hot ball of glowing gases. Its gravity holds the solar system together, keeping everything from the biggest planets to the smallest particles of debris in its orbit. Electric currents in the sun generate a magnetic field that is carried out through the solar system by the solar wind — a stream of electrically charged gas blowing outward from the sun in all directions. ]]> 2018-01-09 22:02:56 UTC https://padlet.com/303994/ihfajn6voete/wish/219994897 303994 https://padlet.com/303994/ihfajn6voete/wish/219995264 Gravity is the force by which a planet or other body draws objects toward its center. The force of gravity keeps all of the planets in orbit around the sun.]]> 2018-01-09 22:04:46 UTC https://padlet.com/303994/ihfajn6voete/wish/219995264 303994 https://padlet.com/303994/ihfajn6voete/wish/219995486 A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth.]]> 2018-01-09 22:05:49 UTC https://padlet.com/303994/ihfajn6voete/wish/219995486 303994 https://padlet.com/303994/ihfajn6voete/wish/219996301 A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter.^[1][2] The word galaxy is derived from the Greek galaxias (γαλαξίας), literally "milky", a reference to the Milky Way. Galaxies range in size from dwarfs with just a few hundred million (10⁸) stars to giants with one hundred trillion (10¹⁴) stars,^[3] each orbiting its galaxy's center of mass.]]> 2018-01-09 22:09:00 UTC https://padlet.com/303994/ihfajn6voete/wish/219996301 303994 https://padlet.com/303994/ihfajn6voete/wish/219996459 Asteroids are rocky, airless worlds that orbit our sun, but are too small to be called planets. Tens of thousands of these minor planets are gathered in the main asteroid belt, a vast doughnut-shaped ring between the orbits of Mars and Jupiter. Asteroids that pass close to Earth are called near-earth objects.]]> 2018-01-09 22:09:39 UTC https://padlet.com/303994/ihfajn6voete/wish/219996459 303994 https://padlet.com/303994/ihfajn6voete/wish/219996926 Comets are cosmic snowballs of frozen gases, rock and dust roughly the size of a small town. When a comet's orbit brings it close to the sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the sun for millions of kilometers.]]> 2018-01-09 22:12:09 UTC https://padlet.com/303994/ihfajn6voete/wish/219996926 303994 https://padlet.com/303994/ihfajn6voete/wish/219997201 All planets can be seen with a small telescope or binoculars and private observatories continue to provide useful information. But the possibility of getting up close with interplanetary spacecraft has revolutionized planetary science. Very little of this site would have been possible without the space program.]]> 2018-01-09 22:13:26 UTC https://padlet.com/303994/ihfajn6voete/wish/219997201 303994 https://padlet.com/303994/ihfajn6voete/wish/219997312 2018-01-09 22:13:55 UTC https://padlet.com/303994/ihfajn6voete/wish/219997312 303994 https://padlet.com/303994/ihfajn6voete/wish/219997394 A meteoroid is a piece of stony or metallic debris which travels in outer space. Meteoroids travel around the Sun in a variety of orbits and at various speeds. The fastest meteoroids move at about 42 kilometers per second. Most meteoroids are about the size of a pebble. When one of these pieces of debris enters the Earth's atmosphere, friction between the debris and atmospheric gases heats it to the point that it glows and becomes visible to our eyes.]]> 2018-01-09 22:14:19 UTC https://padlet.com/303994/ihfajn6voete/wish/219997394 303994 https://padlet.com/303994/ihfajn6voete/wish/219997634 The Moon is an astronomical body that orbits planet Earth, being Earth's only permanent natural satellite.]]> 2018-01-09 22:15:41 UTC https://padlet.com/303994/ihfajn6voete/wish/219997634