The Sun We can’t live without it!!!

Without the Sun, life on planet Earth would be IMPOSSIBLE!!

The Sun does MANY things that make life on this planet possible! Provides the heat needed for life Fuels photosynthesis Keeps the Earth in orbit

Did you Know…? The Sun gives off as much energy as 1 TRILLION megaton bombs…EVERY SECOND!! This energy is what keeps us alive…we use it in a variety of ways that are CRUCIAL to human life!!

Heat The sun's rays hit the equator at a direct angle between 23 ° N and 23 ° S latitude. Radiation that reaches the atmosphere here is at its most intense. In all other cases, the rays arrive at an angle to the surface and are less intense. The closer a place is to the poles, the smaller the angle and therefore the less intense the radiation.

The distribution of global climate zones is caused by the decrease in solar energy as latitude increases from the Equator toward the poles.

The climate of a region will determine what plants will grow there, and what animals will inhabit it.

Two things determine what kinds of crops can grow in an area 1. Temperature 2. Moisture level (precipitation) Without the Heat from the Sun, evaporation and transpiration would STOP. That would end the water cycle… Which would be the end of crops growing. No crops = No food!! No food = No life!!

The Greenhouse Effect The Greenhouse Effect traps in the heat from the Sun and provides the warmth necessary for life on Earth Without the Sun there would be NO HEAT for the atmosphere to trap!!

Without the Sun we would also lose the ozone layer. It is created by the action of the Sun's light on the upper atmosphere. 1.Sunlight splits an O 2 molecule into 2 single O molecules 2.These single O molecules join another O 2 molecule, forming an ozone (O 3 ) molecule

With no ozone, ultraviolet rays (UV-B specifically) are easily able to penetrate the earth's atmosphere and exposure to UV-B rays has been linked to the increased occurrence of cancer, mutations, and immune system diseases. Skin Cancer

The lack of an ozone layer would also result in temperatures that are HIGHER than we can withstand. The land would be unable to hold moisture…therefore we would have no crop growth.

Speaking of crop growth… Sunlight provides the fuel for photosynthesis! Photosynthesis gives us 2 ESSENTIAL things… FOOD and OXYGEN In one way or another ALL FOOD is made from the SUN!!

No Sun = No Photosynthesis No Photosynthesis = No FOOD and No OXYGEN NO LIFE!! Remember the K- T Extinction? What caused the extinction of the dinosaurs?

EVERY living thing needs ENERGY to survive. PRODUCERS make their own food through PHOTOSYNTHESIS (plants mostly) CONSUMERS cannot do this so they MUST EAT to get their energy. ALL of the energy in the food chain originally came from the SUN!!

THE BIGGER AN OBJECT…THE STRONGER ITS GRAVITATIONAL PULL!! Without the Sun’s gravitational pull the Earth would float through space. Some scientists believe that Earth would eventually be pulled into orbit around Jupiter. How massive is the Sun? It contains 99.8% of ALL MATTER in our Solar System. The Sun is big enough that it could hold 1.3 MILLION Earths inside of it!! The Sun Keeps Earth in Orbit

If the Sun ‘shut off’…how long would we survive…and what would life be like?

It would take 8 minutes for us to even realize that the Sun shut off. It would take that long for darkness to reach us. Within a week the global temperature would drop below 0°F. With a year, it would drop to -100°F The top layer of the oceans would freeze over. Ironically, this would insulate the deep water below and would prevent the oceans from freezing solid for hundreds of thousands of years. Eventually our planets temperature would reach -400°F (the temperature at which the heat radiating from the planets core would equal the heat that the Earth radiates into space.)

Although some microorganisms (bacteria, etc.) living in the Earth’s crust MIGHT survive, the MAJORITY of life would only enjoy a BRIEF post-sun existence. Photosynthesis would stop IMMEDIATELY, and most plants would die within a few weeks. With the food chain’s bottom tier knocked out most animals (HUMANS INCLUDED) would die off quickly without food. Scavengers (animals that eat dead matter) could live off the rest of us dead guys for quite a while…until the cold eventually kills them too!!

But, what will most likely happen is humans will be extinct long before the Sun burns out, but if we were around still, maybe this is what we would expect. Video Clip

Classwork/Homework Assignment Your assignment is to construct a book/pamphlet about the sun…and why it is ESSENTIAL for LIFE! The following must be included in your book: 1. The Sun’s influence on : a. Heat of the planet b. Ozone layer c. Photosynthesis d. Food Chains e. Earth’s orbit 2. At least 1 colorful picture for EACH influence above.