On Saturday, October 14, nearly a billion people across much of North and South America will be able to watch Amavasya revolves between Sun And Earth will produce one of the most interesting astronomical phenomena: an eclipse of the Sun.
This eclipse is annular, with a ring of sunlight visible around the image of the Moon at the central point of the scene. However, most of the United States will see only a partial eclipse.
In an annular eclipse the Sun never completely hides (as it does in a total eclipse) because on October 14, the Moon will be 4.5 days past its apogee – the point in its orbit where it is farthest from Earth. The new moon will be 246,707 miles (397,037 km) away on the day of the eclipse. As a result, the tip of its deep umbra cone fails to make contact with Earth for about 12,000 miles. So, like a penny placed on top of a nickel, the Moon’s disk will appear too small to completely cover the Sun. The magnitude or fraction of the Sun’s width that the Moon covers means that 4.8 percent of that width is visible all around.
Connected: Annular solar eclipse 2023: Everything you need to know about North America’s ‘Ring of Fire’ eclipse
Read more: This month there will be 2 eclipses on Earth. Here’s what you need to know
From the moment the eclipse path begins over the northern Pacific Ocean, it slides on a southeastward trajectory, reaching the coast of Oregon at 9:15 a.m. Pacific Daylight Time. For the next 46 minutes, the annular phase will be visible over parts of nine states running from Oregon to Texas; The width of the shadow path averages 127 miles (204 km).
The annular period along the center of the eclipse path will increase steadily from 4 minutes 34 seconds on the Pacific coast of Oregon to 5 minutes 2 seconds on the Texas Gulf Coast. Cities that will experience the “Ring of Fire” effect include Eugene, OR, Winnemucca, NV, Albuquerque, NM, San Antonio and Corpus Christi, Texas.
After leaving Texas, the eclipse path will pass through Mexico’s Yucatan Peninsula, then through Central America (where the greatest eclipse occurs in the Caribbean Sea off the coast of southern Nicaragua), then through northern Brazil and south-central Colombia. Will enter. Before eventually ending up on the open ocean waters of the South Atlantic.
Comparing a total eclipse with an annular eclipse is like comparing night and day. The enormity of the events accompanying a total eclipse is remarkable and astronomers will travel halfway around the world to see and experience them.
An annular eclipse is not the same as totality: the sky is not much darker than in a deep partial eclipse; The Sun’s glorious corona, and “edge effects” such as the chromosphere and shadow bands may not appear. Nevertheless, it is still a spectacular sight, and enthusiasts will head to the part of the eclipse track where it will be most easily accessible for them.
And yet there will come one Time The occurrence of a total eclipse of the Sun would be impossible because the Moon, as seen from Earth, would be too small in apparent angular size to completely cover the Sun’s disk.
ever-changing celestial geometry
The Moon revolves around the Earth in an elliptical orbit. At closest to Earth (perigee), the Moon can reach within 221,439 miles (356,371 km), while its absolute distance from Earth (apogee) is 252,724 miles (406,720 km). The average distance of the Moon from Earth is 239,071 miles (384,748 km).
For a total eclipse to occur, the Moon’s dark shadow cone must make contact with Earth’s surface. When the shadow touches the Earth, it is essentially the tip of the shadow cone and in most cases, that dark shadow is on average about 80 miles (130 km) in width. Anywhere within that shadow, a total eclipse of the Sun will be experienced, in which the Moon’s dark disk completely covers the Sun’s disk.
But the cone of the Moon’s shadow – generally speaking – averages only 235,000 miles (378,000 km) long.
This is less than the average distance of the Moon from the Earth.
That is why, when a new moon passes directly between Earth and the Sun, if – generally speaking – it is more than 235,000 miles (378,000 km) apart, the tip of the dark umbra will fail to make contact with Earth; Instead, a “negative shadow” is created known as an antumbra and it is from within that shadow – as will be the case on October 14 – that an annular or annular eclipse will be viewed.
We are fortunate that, at this particular moment in history, there are times when the new moon can come closer to Earth than average and on such occasions, the tip of its dark shadow can reach Earth and produce total Solar Eclipse,
Final extinction of total eclipses of the Sun
From July 1969 to December 1972, twelve Apollo astronauts left a series of laser reflectors on the Moon’s surface. Since then, astronomers on Earth have regularly bounced lasers off those reflectors. By timing the round trips of those laser pulses, the distance to the Moon can be measured with great precision. Analysis of these measurements has shown that the average distance from the Moon to Earth is increasing at a rate of 1.5 inches (about 3.8 cm) each year.
Why is this happening?
The Moon’s motion is greatly disturbed by the attraction of the Sun and to a lesser extent by the attraction of the planets and the Earth. Tidal effects are causing the Moon to gradually move away from Earth, rotating outward and climbing into a more distant orbit. Of course, as the Moon gets progressively farther away, its apparent size will decrease and eventually it will reach a point where it will be too far for its dark shadow cone to reach the Earth and thus the full Sun. The incident of eclipse can be prevented.
In his book, “More Mathematical Astronomy Morsels” (Willman-Bell, Inc. 2002), the distinguished celestial calculator, Gene Meese, states that it is doubtful that the Moon’s current recession rate from Earth is 12.5 feet (3.8 m) per second. The century will remain stable. If this happens, it would take 1.21 billion years for a total eclipse of the Sun to become impossible.
However, if we also take into account the fact that the eccentricity (shape) of the Earth’s orbit changes at a faster rate than the much slower, gradual increase of the Moon’s distance, we probably won’t have to wait that long.
“As a result,” Meeus notes, “from 620 million to 1210 million years in the future, there will be a period during which total solar eclipses will be alternately possible and impossible, until eventually those totals will remain impossible forever.”