An eclipse is a phenomenon that occurs when one celestial body casts a shadow on another. From Earth, we can observe two types of eclipses: Solar and lunar.
In both occurrences, Earth, the Moon, and the Sun align. However, factors like Earth and the Moon’s ever-changing positioning in space makes different types of solar and lunar eclipses possible.
Check out the Upcoming Eclipses tab to view times and locations.
Upcoming EclipsesA solar eclipse happens when the Moon passes between the Sun and Earth, casting a shadow on Earth. The Moon’s shadow moves in a line across Earth’s surface, creating an eclipse path. As the eclipse unfolds, people along the eclipse path can observe the Moon pass directly in front of the Sun's disk, causing a period of darkness. The extent and duration of this darkness varies depending on the type of eclipse taking place. Generally, solar eclipses span only minutes.
For example, total solar eclipses are most visible to people who are located in the path of totality, or the centermost part of the Moon's shadow. This part of the shadow, known as the umbra, is the darkest. Viewers outside this narrow path may fall within the penumbra, a partly shaded region on Earth where a partial eclipse can be observed. There are four main types of solar eclipses: Total eclipse, partial solar eclipse, annular eclipse, and hybrid solar eclipse.
When the Moon passes between the Sun and Earth, fully blocking the Sun’s face, a total solar eclipse occurs. From Earth, the sky will look dark. Even though the Moon is much smaller than the Sun, it can completely block the Sun ray’s during a total solar eclipse due to its proximity to Earth.
During a partial solar eclipse, the Moon blocks only a portion of the Sun’s disk. The Sun, Moon, and Earth are near alignment, but it’s not enough to fully block the Sun’s face. As a result, the Moon’s partial shadow (penumbra) casts on Earth, but the umbra does not. Viewers standing in the penumbra of a total eclipse will observe a partial eclipse.
An annular eclipse occurs when the Moon blocks all but the outer layer of the Sun, creating a glowing ring in the sky sometimes referred to as a ring of fire, or annulus. The distance between the Earth, Moon, and the Sun is in constant flux due to the Earth and Moon’s elliptical orbits in our solar system. Though the Sun is much larger than the Moon, its distance from Earth causes it to appear the same size as the Moon in our sky. When Earth reaches a point in its orbit where it’s closer to the Sun, the Moon appears slightly smaller than the Sun in comparison. This is when an annular eclipse can occur, creating the appearance of a glowing ring in the sky.
Hybrid solar eclipses are the rarest type of solar eclipse, with viewers on Earth witnessing either a total or annular eclipse depending on their location.
A lunar eclipse takes place when Earth passes between the Sun and the Moon, casting a shadow on the Moon. Lunar eclipse viewing must take place at night, as the viewer must also be standing in Earth’s shadow, facing the Moon. There are two main types of lunar eclipses: Total lunar eclipses and partial lunar eclipses.
For example, total solar eclipses are most visible to people who are located in the path of totality, or the centermost part of the Moon's shadow. This part of the shadow, known as the umbra, is the darkest. Viewers outside this narrow path sometimes fall within the penumbra, a partly shaded region on Earth where a partial eclipse can be observed. There are four main types of solar eclipses: Total eclipse, partial solar eclipse, annular eclipse, and hybrid solar eclipse.
During a total lunar eclipse, the Sun, Earth, and Moon fully align, causing Earth’s shadow to completely engulf the Moon. However, some light bends through Earth’s atmosphere, filtering out blue rays of light and illuminating the Moon a reddish hue.
During a partial lunar eclipse, Earth’s shadow only partially covers the Moon, as the name suggests.
Solar eclipses in general occur about two to five times per year, but hardly any make headlines because they’re not visible from land. A total solar eclipse, where the Moon completely blocks the Sun, is a rare event that can only be seen from a small portion of the Earth's surface. On average, a total solar eclipse occurs somewhere on Earth once every 18 months. However, the frequency of total solar eclipses varies over time due to the fluctuating distance between the Earth and the Moon, as well as the Moon’s changing tilt within its orbit.
However, the recurrence of a solar eclipse in a given location is much more rare. If a total solar eclipse happens at a particular point on Earth, the next total solar eclipse to pass over the same coordinates usually won’t happen again for several decades, or even centuries! This is part of what makes the total solar eclipse of 2017, the Great American Eclipse, and the total solar eclipse of 2024, the Great Northern American Eclipse, so special.
Visit our History of Solar Eclipses blog to find out and learn more about some of the most famous eclipses ever documented.
Solar Eclipses HistoryWhy is recurrence so unlikely? During a solar eclipse, the Moon’s shadow is relatively small, so it moves across the Earth's surface in a narrow path. This “path” is created by the umbra, the darkest portion of the Moon’s shadow. At its widest point, the umbra has a diameter of about 170 km (106 miles). The width of the path of totality can vary, but it is typically about 100 km (62 miles) wide. For reference, the circumference of the Earth is about 40,000 km (24,900 miles), so the Moon’s umbra blankets only a tiny fraction of our planet’s surface.
On the other hand, if a partial solar eclipse occurs in a particular area, the same location may experience another partial solar eclipse within a few years or even sooner. This is because spectators who experience a partial solar eclipse are located within the penumbra, which is much larger than the umbra. It has a diameter of about 6,400 km (3,977 miles). During a partial solar eclipse, the Moon's penumbra can be seen from a much wider area on Earth, where only a portion of the Sun is blocked by the Moon.
It's important to note that the size of the Moon's shadow can also be affected by the Earth's atmosphere, which can refract or bend sunlight and, ultimately, change the shape and size of the shadow on the ground. The width of the eclipse path can also vary within a single solar eclipse, as the distance between the Earth and the Moon varies within a single orbit!
The frequency and timing of solar eclipses in a particular area depend on many factors, including the location of the observer, the type of eclipse, and the movements of Earth, the Moon, and the Sun in relation to each other.
The appearance of the sky during a solar eclipse varies depending on the extent of the eclipse, the location, and the weather conditions. Regardless of these factors, you can expect an amazing spectacle.
During a total solar eclipse, when the Moon completely blocks the Sun, the sky can become very dark–similar to twilight. In fact, it can become so dark that stars and planets become visible in the sky. This is because the Moon blocks out the Sun's bright light, allowing dimmer objects to shine through. People lucky enough to be in the path of totality experience a few minutes of total darkness in the middle of the day, which is a truly awe-inspiring sight. The landscape darkens, the temperature cools like it’s night, and some animals even display their usual nighttime behaviors.
Just moments before and after totality, viewers can often observe what’s called the “diamond ring effect.” Near totality, the Moon blocks all but the corona and a sliver of sunlight, creating the illusion of a band with a sparkly diamond.
One of the most striking effects of a total solar eclipse is the appearance of the Sun's corona, a faint outer atmosphere that is normally invisible to the naked eye. The corona becomes visible as a glowing, white halo surrounding the dark disk of the Moon. It shoots out wispy streams of plasma from the Sun’s surface, creating a dramatic effect against the Moon’s silhouette and a lasting impression on all who witness it.
Since the Sun remains visible, an annular eclipse doesn’t change the lighting as dramatically as a total eclipse would. The sky doesn’t appear as dark, and the corona doesn’t shine through. The next annular eclipse takes place later this year on Saturday, October 14, 2023. Check out our Upcoming Eclipses visibility chart to see where and when to view it.
During a partial eclipse, the Moon blocks a portion of the Sun, making it appear crescent-shaped from Earth. The sky effect is more subtle compared to total or annular eclipses; the lighting dims and the atmosphere takes on a reddish hue, similar to Sunset. Shadows may also look slightly distorted or blurred, due to the lighting.
Illuminate the science of solar eclipses with our collection of free eclipse activities—designed for students of all ages!
Activities & ResourcesOn Monday, April 8th, 2024, a total solar eclipse - the Great North American Eclipse - will cross over North America. The path of totality will span up across Mexico, the United States, and into Canada. This will be the first total solar eclipse visible to North Americans since the Great American Eclipse of 2017, and the last total solar eclipse to cross the continent until 2045. If you’ve never witnessed the stunning spectacle of a total solar eclipse, you won’t want to miss this awe-inspiring event!
Location | Duration of Totality | Partial Eclipse Begins | Total Eclipse Begins | Partial Eclipse Ends |
---|---|---|---|---|
Mazatlán, Sinaloa | 4m 14s | 10:51 AM MDT | 12:07 PM MDT | 1:32 PM MDT |
Torreón, Coahuila | 4m 15s | 11:59 AM CDT | 1:16 PM CDT | 2:41 PM CDT |
Austin, TX | 1m 53s | 12:17 PM CDT | 1:36 PM CDT | 2:58 PM CDT |
Dallas, TX | 3m 47s | 12:23 PM CDT | 1:40 PM CDT | 3:02 PM CDT |
Fort Worth, TX | 2m 34s | 12:22 PM CDT | 1:40 PM CDT | 3:01 PM CDT |
Cleveland, OH | 3m 50s | 1:59 PM EDT | 3:13 PM EDT | 4:28 PM EDT |
Buffalo, NY | 3m 45s | 2:04 PM EDT | 3:18 PM EDT | 4:32 PM EDT |
Rochester, NY | 3m 40s | 206 PM EDT | 3:20 PM EDT | 4:33 PM EDT |
Syracuse, NY | 1m 26s | 2:09 PM EDT | 3:23 PM EDT | 4:34 PM EDT |
Montréal, Québec | 1m 12s | 2:14 PM EDT | 3:26 PM EDT | 4:36 PM EDT |
It is never safe to look directly at the Sun. Looking directly at the Sun during a solar eclipse–or ever–is very dangerous, and can cause permanent eye damage or blindness. To protect your vision, specialized solar viewing glasses or indirect viewing methods should always be used to observe a solar eclipse.
If you plan to view a solar eclipse using specialized glasses, be sure to check that they’re legitimate. Solar eclipse glasses should be thoroughly inspected and meet specific safety requirements for certification.
Other viewing methods, such as a pinhole projector, allow solar eclipses to be observed indirectly to protect your eyesight. Most indirect viewing methods can be constructed in less than an hour using some common household materials. Check out our Eclipse DIY Handbook to learn how you can build pinhole projectors with your class. For more safety tips, visit our blog, Solar Glasses & Eclipse Safety.
Engage students in a mini engineering project by constructing your own pinhole projectors!
View Project DetailsSolar eclipses affect the weather more than you might think. As the Moon’s shadow passes over Earth, it blocks out the Sun’s light and heat. Even though it only lasts a matter of minutes, this darkness can change the atmosphere.
As the Moon passes between the Sun and the Earth, it casts two shadows on Earth’s surface: The umbra and penumbra. People who fall within the umbra will witness a total solar eclipse. Since sunlight is completely blocked out, the ground and air within this shadow cools. In fact, temperature drops about 5ºC on average during a solar eclipse. During the 2001 eclipse in Lusaka, Sambia, temperature was recorded to drop close to 8ºC. People viewing the sky from the penumbra, however, will likely experience a more subtle drop in temperature.
During a solar eclipse, changes in temperature are often followed by changes in wind patterns as the air cools and contracts. Generally, wind dies down and shifts direction during a solar eclipse. Known as “eclipse wind,” this change in air movement was first noted by astronomer Edmund Halley about 300 years ago. The explanation for the shift in wind pattern remained largely a mystery until the 2015 eclipse when UK scientists participated in a National Eclipse Weather Experiment: They found that when the Moon passed in front of the Sun, the ground cooled rapidly, halting the rise of warm air. This cooling of air creates pressure gradients between Earth’s boundary layers (layers of the atmosphere) which causes changes in wind speed and direction.
Clouds form when the moisture in the air reaches saturation. When the air can no longer hold any more water vapor, the excess water vapor condenses into droplets, which can form clouds. Saturation can occur in two ways: a change in temperature or a change in relative humidity. Warm air is capable of holding more moisture than cold air, so a sudden drop in temperature can lead to moisture saturation, triggering cloud formation. Often, this drop in temperature occurs as water vapor rises and meets colder air, forming a cloud. When there is a change in humidity, more and more droplets of water accumulate, increasing the relative humidity until a cloud forms.
When a solar eclipse occurs, the air cools, increasing relative humidity; so we would anticipate the new formation of clouds. However, cloud dispersion during solar eclipses is a well-documented phenomenon. The reason for this is unclear, but it is likely due to the loss of solar radiation hitting the ground. Rather than reaching the ground, the solar radiation is blocked, which prevents water from evaporating into the air. During the 2017 total solar eclipse, for example, clouds dissipated across the United States; they initially formed due to high humidity and lots of sunlight, but when the temperature dropped, the cooler air couldn’t sustain the moisture. Pressure and temperature gradients between boundary layers also play a role in determining whether clouds will develop or disperse, as well as pre-existing weather conditions.
Solar eclipses can potentially affect precipitation by triggering changes in atmospheric temperature and pressure, although the effects are usually small and localized. In some cases, a solar eclipse can cause a decrease in precipitation by reducing the amount of solar energy available to drive the water cycle. This effect is usually short-lived, however, and is unlikely to have a significant impact on overall precipitation patterns.
On the other hand, a solar eclipse can increase precipitation in some regions where the cooling effect forces moisture to condense and form clouds, leading to rain or snow. However, the effect is usually small and is limited to areas that are already experiencing unstable atmospheric conditions.
The effects of a solar eclipse on precipitation are relatively minor and depend on a variety of factors, including the weather conditions before and during the eclipse, as well as the location and time of day.
Illuminate the science of solar eclipses with our collection of free eclipse activities—designed for students of all ages!
Activities & ResourcesWant to conduct your own experiments during this year’s solar eclipse? Give your students the science experience of a lifetime with these free solar eclipse activities. These free activities can be performed with students of all ages and include step-by-step instructions, analysis questions, and preformatted software files for students.
In this lab, students become junior eclipse scientists as they use Wireless Light and Temperature Sensors to track how light and temperature change during a solar eclipse.
View Activity Eclipse Light & Temp BundleStrange things happen during a solar eclipse! This lab lets students uncover local changes in weather conditions using a Wireless Weather Sensor with GPS.
View Activity Eclipse & Weather BundleIn this sensor-free activity, students use UV beads to compare the effectiveness of sunglasses and eclipse glasses in blocking UV light.
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