Astrophysics- Physics

What is mass?

the amount of matter in a substance (kg)

What is weight?

the force of gravity on an object (N)

What is a gravitational force field?

how much an object is pulled towards the center of a celestial body (any natural object that exists in space outside of Earth's atmosphere) object/planet (n/kg)

What is gravity?

Gravity is a force that pulls things together. It's what keeps us on the ground and makes things fall down when we drop them. It's why planets stay in orbit around stars like our Sun.

What is the formula for weight?

Weight= gravitational field * mass

What are the requirements to be a planet?

1. it must be big enough to clear it’s surroundings

2. must be big enough for gravity to make it spherical

3. must orbit a star

What is a galaxy?

A collection of dust, gas, billions of stars and their planets held together by gravity. Our solar system is in the milky way.

What are the 3 types of galaxies?

Spiral, elliptical, and irregular are the three main types of galaxies in the universe.

What is a light year?

A light year is the distance light travels in one year, approximately 9.46 trillion kilometers or about 5.88 trillion miles.

How are stars formed?

1. A nebula is made out of gas, dust, and rocks

2. over time, gravity clumps it together

3. this causes pressure to increase

4. then temperature increases

5. eventually, temperature increases so much that fusion starts

6. once fusion starts, a star is formed.

What is our main source of heat and light?

The Sun.

Why do we have seasons?

We have seasons because Earth's axis is tilted as it orbits around the Sun. This tilt means that different parts of Earth receive varying amounts of sunlight throughout the year, which causes changes in temperature and weather patterns.

When a part of Earth is tilted toward the Sun, it gets more direct sunlight and experiences warmer temperatures, creating summer in that hemisphere. Meanwhile, the hemisphere tilted away from the Sun receives less direct sunlight and experiences cooler temperatures, leading to winter there.

Explain the difference between a geocentric and heliocentric system.

In a geocentric system, people believed that Earth was at the center of the universe and that all celestial bodies, like the Sun, stars, and planets, revolved around it. This was the prevailing view in ancient times and was supported by thinkers like Ptolemy.

On the other hand, in a heliocentric system, the Sun is at the center of the solar system, and the planets, including Earth, revolve around it. This model was proposed by ancient Greek astronomers like Aristarchus but gained widespread acceptance with the work of Copernicus during the Renaissance.

What 2 things would happen if the earth had no tilt?

1. No Seasons: Earth's tilt is what causes the seasons by varying the amount of sunlight different parts of the planet receive throughout the year. Without this tilt, the amount of sunlight reaching each hemisphere would remain constant, leading to a lack of seasonal changes. This means there would be no summer, fall, winter, or spring as we know them.

2. Consistent Climate: Without the tilt causing seasonal changes, the climate in each region would be much more consistent throughout the year. Areas near the equator would still experience warm temperatures, while regions closer to the poles would remain colder. However, there would be no temperature variations due to seasonal shifts.

What are living conditions like on the moon?

Living conditions on the Moon are harsh due to its lack of atmosphere, extreme temperatures, absence of water, and low gravity. These factors make it impossible for humans to survive without specialized suits, habitats, and extensive supplies.

Name the order of our planets in the solar system.

1. Mercury

2. Venus

3. Earth

4. Mars

5. Jupiter

6. Saturn

7. Uranus

8. Neptune

(And after Neptune, there's a region called the Kuiper Belt where you can find dwarf planets like Pluto.)

What is the difference between meteors, meteoroids, and meteorites?

1. Meteoroids: These are small rocky or metallic objects that travel through space. They are smaller than asteroids and can range in size from a grain of sand to several meters across.

2. Meteors: When a meteoroid enters Earth's atmosphere and burns up due to friction with the air, it creates a bright streak of light in the sky known as a meteor or "shooting star." Meteors are often visible to the naked eye and are most commonly observed during meteor showers.

3. Meteorites: If a meteoroid survives its passage through Earth's atmosphere and lands on the ground, it is called a meteorite. Meteorites can vary in size from tiny fragments to large boulders and can provide valuable insights into the composition and history of our solar system.

If a girl has a mass of 40 kg and she lives on earth (10N/ kg), what is her weight?

Weight = mass × gravitational acceleration

Given: Mass = 40 kg Gravitational acceleration on Earth = 10 N/kg

Weight = 40 kg × 10 N/kg

Weight = 400 N

So, the girl's weight on Earth would be 400 Newtons.

How does a lunar eclipse happen?

A lunar eclipse occurs when Earth passes between the Sun and the Moon, casting its shadow on the Moon. This can only happen during a full moon when the Sun, Earth, and Moon are aligned in a straight line, with Earth in the middle. There are three types of lunar eclipses:

Why do we see moon phases?

We see moon phases because of the changing positions of the Moon, Earth, and Sun relative to each other. The Moon orbits around Earth, and as it does, different portions of its illuminated surface become visible from Earth, creating the various moon phases.

Name all the moon phases in order:

1. New Moon

2. Waxing Crescent

3. First Quarter

4. Waxing Gibbous

5. Full Moon

6. Waning Gibbous

7. Last Quarter

8. Waning Crescent

What objects are in our solar system (give examples)?

1. Moons: Natural satellites orbiting planets, such as Earth's moon (Luna), Jupiter's moons (Io, Europa, Ganymede, Callisto), and Saturn's moons (Titan, Enceladus, Mimas).

2. Asteroids: Small rocky objects orbiting the Sun, such as Ceres, Vesta, and those found in the asteroid belt between Mars and Jupiter.

3. Comets: Icy bodies that orbit the Sun, like Halley's Comet, Comet Hale-Bopp, and Comet NEOWISE.

4. Meteoroids: Small rocky or metallic objects traveling through space, ranging in size from dust grains to boulders.

5. Dwarf planets: Pluto, Eris, Haumea, Makemake, and Ceres, which are smaller than planets but larger than asteroids.

6. Planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and dwarf planets like Pluto.

What did Keplen discover?

Kepler discovered three important rules about how planets move around the Sun by carefully studying the sky. He noticed that planets move in oval paths called ellipses and that they speed up when they're closer to the Sun. He also found out that the time it takes for a planet to orbit the Sun depends on how far away it is. These discoveries changed our understanding of the solar system.

What are Jovian planets?

Jovian planets, or gas giants, are large planets made mostly of gases like hydrogen and helium. Examples include Jupiter, Saturn, Uranus, and Neptune. They lack solid surfaces and have thick atmospheres, many moons, and sometimes rings.

Explain the lifetime of a high-mass star:

High-mass stars burn bright and fast. They quickly use up their hydrogen fuel, becoming red supergiants, and eventually explode in a supernova. This entire process can take only a few million years.

What’s the difference between a comet and an asteroid?

1. Composition: Comets are composed mostly of ice, dust, and rocky material, while asteroids are primarily made of rock and metal.

2. Appearance: Comets often have a bright coma (a cloud of gas and dust) and a tail when they are close to the Sun due to the heat causing their icy surface to sublimate. Asteroids generally have irregular shapes and do not develop tails.

3. Orbits: Comets typically have highly elliptical orbits that can take them far from the Sun and then swing them close to it, whereas asteroids generally have more circular orbits and tend to stay within the asteroid belt between Mars and Jupiter.

4. Size: Comets are often smaller than asteroids, but there are exceptions.A

When are the solstices?

A solstice is a point in the Earth's orbit around the Sun where the North Pole (during the summer solstice) or the South Pole (during the winter solstice) is tilted closest to the Sun. It marks the longest day (summer solstice) or shortest day (winter solstice) of the year depending on which hemisphere you're in.

What seasons are the hemispheres in?

In the Northern Hemisphere, the seasons are as follows:

1. Spring: Begins around March 20th and ends around June 21st.

2. Summer: Begins around June 21st and ends around September 22nd.

3. Autumn (Fall): Begins around September 22nd and ends around December 21st.

4. Winter: Begins around December 21st and ends around March 20th.

In the Southern Hemisphere, the seasons are opposite:

1. Spring: Begins around September 22nd and ends around December 21st.

2. Summer: Begins around December 21st and ends around March 20th.

3. Autumn (Fall): Begins around March 20th and ends around June 21st.

4. Winter: Begins around June 21st and ends around September 22nd.

What is pluto?

A dwarf planet.

What is a solar eclipse?

when the moon passes exactly in between the earth and the sun, blocking sunlight from reaching a specific part of earth.

What is the 'red moon’/ ‘blood moon’?

A 'red moon' or 'blood moon' occurs during a total lunar eclipse when the Earth's shadow casts a reddish hue on the moon's surface.

What is an umbra?

the darker, center part of the shadow.

What is a penumbra?

the lighter, outer part of a shadow.