![TITLE: UNIVERSE AND SPACE
SUBTITLE: CLASS 7 SCIENCE
PRESENTED BY: [ASHOK J]](https://image.slidesharecdn.com/7th-250806020137-2f9c3ff6/85/CLASS-7-Universe-and-Space-English-medium-1-320.jpg)
CLASS 7 Universe and Space - English medium
- 1. TITLE: UNIVERSE AND SPACE SUBTITLE: CLASS 7 SCIENCE PRESENTED BY: [ASHOK J]
- 2. INTRODUCTION TO THE UNIVERSE • The universe is everything that exists: space, time, matter, and energy. • The universe is vast and ever-expanding. • It contains galaxies, stars, planets, moons, asteroids, comets, and more. • size comparison
- 3. WHAT IS SPACE? • Space is the vast, seemingly empty expanse that exists beyond Earth’s atmosphere. • It is where all celestial bodies like stars, planets, and galaxies exist. • Space is mostly empty, but it also contains gases, dust, and radiation.
- 4. THE SOLAR SYSTEM • Our Solar System is part of the Milky Way Galaxy. • The Sun is at the center, and 8 planets orbit around it. • The 8 planets in order from the Sun are: Mercury,Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. • There are also dwarf planets, moons, asteroids, and comets in the Solar System. • Solar System
- 5. GEOCENTRICTHEORY • The GeocentricTheory (from "Geo" meaning Earth) is the belief that Earth is at the center of the universe. • According to this theory, all other celestial bodies, including the Sun, planets, and stars, revolve around Earth. • This model was widely accepted in ancient civilizations, especially by the Greek philosopher Claudius Ptolemy (2nd century AD). • It was the dominant belief in many ancient cultures for over 1,400 years. This Photo by Unknown Author is licensed under CC BY-NC
- 6. This Photo by Unknown Author is licensed under CC BY Heliocentric Theory •The Heliocentric Theory (from "Helio" meaning Sun) is the theory that the Sun is at the center of the Solar System, and the planets revolve around it. •This theory was proposed by the Polish astronomer Nicolaus Copernicus in the 16th century. •It replaced the Geocentric Theory and paved the way for modern astronomy. •Galileo Galilei and Johannes Kepler later supported this theory with their observations.
- 7. KEY DIFFERENCES BETWEEN GEOCENTRIC AND HELIOCENTRICTHEORY
- 8. PHASES OFTHE MOON •The Moon goes through a cycle of phases as it orbits Earth. •The Moon's phases are caused by the changing relative positions of the Earth, Moon, and Sun, which affect how much of the Moon’s surface is illuminated by the Sun. This Photo by Unknown Author is licensed under CC BY
- 9. THE 8 PHASES OF THE MOON 1. New Moon:The Moon is between Earth and the Sun, so the side of the Moon facing Earth is not illuminated. 2. Waxing Crescent:A small sliver of the Moon begins to be illuminated on the right side. 3. First Quarter: Half of the Moon is illuminated, with the right half visible from Earth. 4. Waxing Gibbous: More than half of the Moon is illuminated, but it’s not yet full. 5. Full Moon:The entire face of the Moon is illuminated and visible from Earth. 6. Waning Gibbous:After the full Moon, the illuminated part starts to decrease on the left side. 7. Last Quarter: Half of the Moon is illuminated, with the left half visible. 8. Waning Crescent:A small sliver remains, and the Moon is preparing to return to the New Moon phase.
- 10. THE MOON'S PHASES IN A LUNAR CYCLE • The Moon's phases take about 29.5 days to complete a full cycle, from one New Moon to the next. • The phases repeat in a regular pattern and are visible in different parts of the world at different times of the month. • The cycle of the Moon's phases is what gives rise to the concept of a "month" in many cultures.
- 11. EPICYCLES OF THE MOON •Epicycles were used in the Geocentric Theory to explain the complex motions of planets and the Moon in the sky. •According to Ptolemaic astronomy, planets and the Moon did not move in perfect circles around Earth. Instead, they moved along small circles, called epicycles, while simultaneously moving along larger circular orbits (called deferents). •The Moon's motion was explained through epicycles as it seemed to change speed and direction as it traveled around Earth. •The epicycle model helped explain phenomena like retrograde motion, where planets appear to move backward in the sky. •epicycle This Photo by Unknown Author is licensed under CC BY-SA
- 12. STARS AND CONSTELLATIONS • A star is a huge ball of hot gas that emits light and heat. • The Sun is the closest star to Earth. • Constellations are groups of stars that form patterns in the sky. • Example:The Big Dipper, Orion. This Photo by Unknown Author is licensed under CC BY-SA
- 13. THE MILKYWAY GALAXY The Milky Way is the galaxy that contains our Solar System.It is a spiral galaxy with billions of stars.Our Sun is just one star in the Milky Way.