Direct sunlight reaches the Earth's surface when there is no cloud cover between the sun and the Earth, while cloud cover causes indirect sunlight to reach the surface. In gardening, sunlight falling directly on the plant is direct sunlight, while indirect sunlight refers to shaded areas.
Indirect sunlight also is called diffuse sky radiation, because it is sunlight that reaches the Earth’s surface after being dispersed in the atmosphere over haze, dust, and clouds.
Whether you’re tracking global weather patterns, collecting solar energy, or simply planning out your garden, you can benefit from an understanding of direct and indirect sunlight. Below, we’ll explain the difference and why it matters to you!
When it comes to sunlight, knowing the difference between direct and indirect can not only provide a deeper understanding of how our solar system works, but it can have a practical implication as well: About two-thirds of solar energy that heads towards Earth scatters or deflects before actually reaching the surface, so knowing where the light is direct and where it is indirect can make a difference when it comes to using the Sun’s energy efficiently and effectively.
An Overview of Direct vs. Indirect Light
Let’s start with a short refresher on the set up of our solar system, shall we? The Sun is our closest star, and the Earth –– along with the other planets in our solar system –– revolve around it. The Sun provides us with nearly all of our energy and heat here on Earth, and it is responsible for day and night, seasons, climate, weather, and, of course, pesky sunburns.
Depending on the time of year, the angle at which the Sun’s rays strike the Earth will vary, and the difference between the quality and intensity of that light is split into two primary categories: direct and indirect sunlight.
When the Sun is high in the sky and directly casting its rays on the surface, especially in the summer months, this is direct sunlight. So what does direct sunlight mean for us here on Earth, exactly? Direct sunlight is more concentrated heat, which tends to be warmer but also covers a smaller surface area.
During the winter months, the Sun is lower in the sky and its rays strike the Earth at an oblique angle, otherwise known as indirect sunlight. Indirect sunlight is more diffuse and it also covers a broader surface area. This comes at the cost of temperature; cold winters are partially an effect of indirect sunlight.
What Parts of Earth Receive Direct and Indirect Sunlight?
Because the Earth is round and spinning on its axis, there are certain geographical locations which receive more direct sunlight than indirect sunlight, and visa versa. For example, areas near the Earth’s equator, such as Central America and Southern Africa, receive more direct sunlight throughout the year. In fact, the equator is where the direct sunlight is nearly at a 90-degree angle all year round! That’s why these areas tend to have warmer temperatures all year round.
On the flip side, the North and South poles mostly receive indirect sunlight; the Sun’s rays fall on these areas at extremely oblique angles. This explains the constant cold temperatures of places like Antarctica and Greenland.
What Does Direct Sunlight Mean for Us?
How does direct and indirect sunlight affect us? It’s a great question, not only for scientists and professors, but for everyone who benefits from the Sun. Areas where which receive more direct sunlight are more likely to sustain crops and capture solar energy through solar panels; areas with more indirect light are going to be cooler and less capable of sustaining crops or capturing energy.
That isn’t to say that the Earth’s poles don’t have their purpose; large masses of glaciers are critical for absorbing excess heat around the planet. In fact, many researchers are concerned by the expedited melting of glaciers due to climate change. Without those large patches of ice, there isn’t anything to control global warming!
Continue Your Study of the Sun
Whether you’re an amateur astronomer or a seasoned eclipse chaser, there is always so much more to learn about the Sun and its relationship to the Earth and our solar system. At Rainbow Symphony, our mission is to provide anyone who is curious about the stars above with the resources they need to continue their study of light and color.
Check out our entire collection solar astronomy tools, eclipse gear, and educational products to find what you need! If you have any questions about our products, just give a shout at 818-708-8400, or by email at firstname.lastname@example.org