Auroras, also known as the Northern Lights, are most commonly visible around the equinoxes in March and September. The Russell-McPherron effect, proposed by geophysicists Christopher Russell and Robert McPherron, explains why Earth experiences more magnetic activity at these times of the year. As the solar wind comes across Earth, the disjunction deflects much of it away from the planet. However, as Earth approaches the equinox, the Earth’s magnetic field lines up with the sun’s. The result is more brilliant auroras. The tilt of Earth’s magnetic field means that they’re largely misaligned, but the Russell-McPherron effect brings the two magnetic fields in prime position to receive the charged particles that cause the auroras. Although the Russell-McPherron effect is the most popular explanation, scientists are still not certain what exactly happens between the solar wind and Earth’s magnetic field to trigger the auroras. Despite this, auroras continue to captivate people around the world with their beautiful, unpredictable light shows.
Equinox on March 20 means more stunning auroras are coming. Here’s why.
Auroras are one of the most spectacular natural phenomena that occur on Earth. They are also known as the Northern Lights, and they are most commonly visible around the equinoxes in March and September. Aurora hunters often claim that these are the best times to see them, and science supports their theory.
Auroras are caused by geomagnetic storms, which are triggered by charged particles from the sun that interact with the Earth’s magnetic field. These storms create stunning displays of light that are visible in the night sky. According to data, auroras peak around the two equinoxes and decline around June and December, the two solstices. Scientists have been trying to understand the correlation between the Earth’s rotation and the occurrence of geomagnetic storms.
The most common explanation is the alignment of Earth’s magnetic field. Although the magnetic poles of the Earth do not match its geographic poles, they are still slanted with respect to the sun. During the equinoxes, Earth’s orbit brings this tilted field into prime position to receive the charged particles that cause the auroras.
Scientists do not agree on a full-color picture of how auroras form, but they do know that they are created by solar wind and its ‘gusts,’ like solar flares and coronal mass ejections. When charged particles stream away from the sun and wash over the Earth, its magnetic field draws them towards high latitudes. These high-energy particles then collide with and excite the atoms of Earth’s upper atmosphere, creating the stunning displays that cascade across the sky.
Geomagnetic storms surge in strength and number twice a year, around the equinoxes, and auroras are only one aspect of the tempests that these particles brew up as they blow over the Earth. According to data, a sizable magnetic storm happens on nearly twice as many days in March as in June or July, proving that auroras are at their most spectacular around the equinoxes.
If you are an aurora hunter, the best time to see them is during the equinoxes in March and September. As the Earth’s magnetic field aligns with the sun, it creates the perfect conditions for charged particles to collide with the Earth’s atmosphere, producing the stunning displays that we know as the Northern Lights. So, if you want to witness this incredible natural phenomenon, make sure you’re looking up at the night sky around the equinoxes.
The Russell-McPherron effect: Why Earth experiences more magnetic activity around the equinoxes
Auroras, also known as the Northern Lights, are one of the most stunning natural phenomena that occur on Earth. They are most commonly visible around the equinoxes in March and September. Scientists have been studying the correlation between the Earth’s rotation and the occurrence of geomagnetic storms that cause these auroras.
In 1973, geophysicists Christopher Russell and Robert McPherron proposed what would become the most accepted explanation of why Earth experiences more magnetic activity at these times of year. Today, scientists call it the Russell-McPherron effect. They determined that the answers lay in how the sun and Earth’s respective magnetic fields meet each other.
The tilt of Earth’s magnetic field means that they’re largely misaligned. As the solar wind comes across Earth, the disjunction deflects much of it away from the planet. However, as Earth approaches the equinox in its orbit, Earth’s azimuthal component lines up with the sun’s. The two magnetic fields end up pointing in opposite directions. The result is guided by similar physics to that which causes the opposing ends of two bar magnets to align. More of the solar wind gets through, resulting in stronger geomagnetic activity, and by extension, more brilliant auroras.
Although the Russell-McPherron effect is the most popular explanation among scientists, it may not be the only cause. Scientists also know that at the equinoxes, the Earth’s magnetic poles fall into a right angle to the direction of the solar wind’s flow, making the solar wind more potent. They call this the “equinoctial effect.”
However, there is still much that scientists don’t know about what causes auroras. They aren’t sure what exactly happens between the solar wind and Earth’s magnetic field to trigger them.
Despite this, auroras continue to captivate people around the world with their beautiful, unpredictable light shows. To stay updated on the latest space news, follow @Spacedotcom, or on Facebook and Instagram.
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