Earth- Sun MotionEarth- Moon Motion

Shara Alyssa A. TolentinoIV-24 BSE Mathematics

SUN QUIZ!

What is the brightest star in our night sky?

a. North Starb. Sirius d. Proxima

Centuari

c. Chiappe

What is the brightest star in our night sky?

a. North Starb. Sirius d. Proxima

Centuari

c. Chiappe

How far away is the Earth from the Sun in light

minutes?

a. 60

b. 8 d. 16

c. 1

How far away is the Earth from the Sun in light

minutes?

a. 60

b. 8 d. 16

c. 1

What is the main composition of the Sun?

a. Hydrogen

& Heliumb. Methane & Hydrogen

d. Hydrogen &

Oxygen

c. Oxygen & Ammonia

What is the main composition of the Sun?

a. Hydrogen

& Heliumb. Methane & Hydrogen

d. Hydrogen &

Oxygen

c. Oxygen & Ammonia

The Sun will last forever.

False

True

The Sun will last forever.

False

True

The average rotation period of the Sun is?

a. 15-20 daysb. It doesn’t rotate

d. 1 Earth day

c. 25-30 days

The average rotation period of the Sun is?

a. 15-20 daysb. It doesn’t rotate

d. 1 Earth day

c. 25-30 days

The Sun will end its life as what?

a. Planetary

nebulab. Will never end

d. Supernova

c. White Dwarf

The Sun will end its life as what?

a. Planetary

nebulab. Will never end

d. Supernova

c. White Dwarf

Sunspots are actually cooler regions on the Sun.

False

True

Sunspots are actually cooler regions on the Sun.

False

True

Sunspots are actually cooler regions on the Sun.

The Sun's energy production takes place

where?

a. The surfaceb. The Core

d. Everywhere

on the Sun

c. The Corona

The Sun's energy production takes place

where?

a. The surfaceb. The Core

d. Everywhere

on the Sun

c. The Corona

Sun or Sol

Is the star at the centre of our solar system and is responsible for the Earth’s climate and weather.

The average radius of the Sun is 695,508 km (109.2 x that of the Earth) of which 20–25% is the core.

Star Profile

Age: 4.6 Billion Years

Surface Temperature: 5500 °C

Type: Yellow Dwarf (G2V)

Circumference at Equator: 4,370,005.6 km

Diameter: 1,392,684 km

Mass: 1,989,100,000,000,000,000,000 billion kg (333,060 x Earth)

One million Earths could fit inside the Sun,

then around 1,300,000 Earths would fit inside.

Earth-Sun Motion

The speed of the Earth’s orbit around the sun is 108,000 km/h.

Earth-Sun Motion

Travels 940 million km during one orbit.

Earth takes about a year or 365 days to travel once around the sun.

Earth-Sun Motion

Earth-Sun Motion

365 days 5 hrs. 48 min. 46 sec. or 365.242199 solar days

Earth doesn’t travel in the path around the sun that returns to its starting point.

Earth-Sun Motion

The sun appears to shift in the sky about 1 degree per day.

Earth-Sun Motion

The planet’s distance from the Sun also varies as it orbits.

Earth-Sun Motion

When the Earth is closest to the Sun, it is said to be at perihelion.

This occurs around January 3rd each year, when the Earth is at a distance of about 147,098,074 km.

Earth-Sun Motion

When it is at its farthest distance from the Sun, Earth is said to be at aphelion;

which happens around July 4th where the Earth reaches a distance of about 152,097,701 km.

Earth-Sun Motion

The average distance of the Earth from the sun is about 149.6 million km, which is also referred to as one astronomical unit (AU).

Earth-Sun Motion

Earth-Sun Motion

How do we know when the year starts or ends?

One way called the Sidereal year, measures our orbit against the distant stars, as viewed from the Earth, our orbit causes the sun to appear the mood through constellations of the zodiac on the path called ecliptic.

Ecliptic is not the same thing as the earth's extended equator, the celestial equator.

The earth's axis (and hence also the celestial equator) is actually tilted by 23.5 degrees with respect to the plane of the earth's orbit, or the ecliptic.

Earth-Sun Motion

The plane of the earth's orbit is called the ecliptic. Since the earth orbits the sun, the sun is also on the ecliptic.

Earth-Sun Motion

Sidereal year (from L. sidus "asterism, star")

-is the time taken by the Earth to orbit the Sun once with respect to the fixed stars. Tropical year or Solar year -is the time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth.

Earth-Sun Motion

This motion is difficult to observe directly, because the stars cannot be seen when the sun is in the sky.

Earth-Sun Motion

If we consider the celestial equator as the reference circle, the ecliptic appears to be inclined, or tilted, 23.5 degrees from the plane of the earth's equator, as demonstrated above.

Earth-Sun Motion

This orientation means that the sun appears to transit the sky north of the celestial equator during part of the year and south of the celestial equator the other part of the year.

Earth-Sun Motion

What is the nature of the Earth’s orbit?

Rather than being a perfect circle, the Earth moves around the Sun in an extended circular or oval pattern.

This is what is known as an “elliptical” orbit.

Earth-Sun Motion

Johannes Kepler, a German mathematician and astronomer. His seminal work Astronomia nova (New Astronomy).

Earth-Sun Motion

An illustration of Kepler’s three laws of motion, which show two planets that have elliptical orbits around the Sun. Credit: Wikipedia/Hankwang

After measuring the orbits of the Earth and Mars,

the orbits of both planets appeared to be speeding up or slowing down.

This coincided directly with the planets’ aphelion and perihelion,

Earth-Sun Motion

An illustration of Kepler’s three laws of motion, which show two planets that have elliptical orbits around the Sun. Credit: Wikipedia/Hankwang

meaning that the planets’ distance from the Sun bore a direct relationship to the speed of their orbits.

It also meant that both Earth and Mars did not orbit the Sun in perfectly circular patterns.

Earth-Sun Motion

An illustration of Kepler’s three laws of motion, which show two planets that have elliptical orbits around the Sun. Credit: Wikipedia/Hankwang

The Earth’s orbit plays a role in the seasons.

Earth-Sun Motion

The four seasons are determined by the fact that the Earth is tilted 23.4° on its vertical axis, which is referred to as “axial tilt.”

Earth-Sun Motion

This quirk in our orbit determines the solstices – the point in the orbit of maximum axial tilt toward or away from the Sun – and the equinoxes, when the direction of the tilt and the direction to the Sun are perpendicular.

A solstice is an astronomical event that occurs twice each year as the Sun reaches its highest or lowest excursion relative to the celestial equator on the celestial sphere.

Earth-Sun Motion

Equinox- the oldest meaning is the day when daytime and night are of approximately equal duration.

Earth-Sun Motion

In short, when the northern hemisphere is tilted away from the Sun, it experiences winter while the southern hemisphere experiences summer.

Six months later, when the northern hemisphere is tilted towards the Sun, the seasonal order is reversed.

Earth-Sun Motion

In the northern hemisphere, winter solstice occurs around

December 21st, summer solstice is near June 21st, spring equinox is around March 20th

and autumnal equinox is about

September 23rd.

Earth-Sun Motion

The axial tilt in the southern hemisphere is exactly the opposite of the direction in the northern hemisphere. Thus the seasonal effects in the south are reversed.

Diagram of the Earths orbit around the Sun. Credit: NASA/H. Zell

Earth-Sun Motion

Earth-Sun Motion

Sun-Earth Lagrange Points. Credit: Xander89/Wikimedia Commons

Another interesting characteristic of the Earth’s orbit around the Sun has to do with Lagrange Points.

These are the five positions in Earth’s orbital configuration around the Sun where the combined gravitational pull of the Earth and the Sun provides precisely the centripetal force required to orbit with them.

Earth-Sun Motion

The five Lagrange Points between the Earth are labelled (somewhat unimaginatively) L1 to L5.

L1, L2, and L3 sit along a straight line that goes through the Earth and Sun.

Earth-Sun Motion

L1 sits between them, L3 is on the opposite side of the Sun from the Earth, and L2 is on the opposite side of the Earth from L1.

These three Lagrange points are unstable.

Earth-Sun Motion

The L4 and L5 points lie at the tips of the two equilateral triangles where the Sun and Earth constitute the two lower points.

Earth-Sun Motion

These points lie along Earth’s orbit, with L4 60° behind it and L5 60° ahead.  These two Lagrange Points are stable.

Earth-Sun Motion

References https://www.youtube.com/watch?v=jgoIP90apEs http://cseligman.com/text/sky/moonmotion.htm http://www.windows2universe.org/the_universe/uts/

moon1.html http://www.ucolick.org/~bolte/AY4_00/week1/

motionsC.html http://people.bu.edu/sscruggs/earthandmoonhome.html http://www.polaris.iastate.edu/NorthStar/Unit4/

unit4_sub1.htm https://www.youtube.com/watch?v=82p-DYgGFjI http://space-facts.com/the-sun/ http://www.funtrivia.com/newflash/process.cfm http://cseligman.com/text/sky/moonmotion.htm http://www.funtrivia.com/en/subtopics/Earth-Sun-and-

Moon-276058.html

THANK YOU!