In News:

A total solar eclipse occurred on 12 August 2026, visible across eastern Greenland, western Iceland, northern Russia, northern Spain and parts of Portugal. The event provided an opportunity to study the Sun’s faint corona, normally obscured by the bright photosphere.

Key Facts

• Solar Eclipse: Occurs when the Moon comes between the Sun and Earth, blocking sunlight.
• Occurs only during a New Moon when the three bodies are suitably aligned.
• The Moon’s orbit is inclined by about 5° to the ecliptic, so eclipses do not occur every New Moon.
• There are generally two eclipse seasons each year.

Types of Solar Eclipse

1. Total: Moon completely covers the Sun; visible from the path of totality.
2. Partial: Only part of the Sun’s disc is covered; occurs within the penumbra.
3. Annular: Moon appears smaller than the Sun, producing a “ring of fire”; associated with the antumbra.
4. Hybrid: Appears total from some locations and annular from others.

Why is a Total Eclipse Important for Solar Studies?

• Corona: During totality, the Moon blocks the photosphere, allowing direct observation of the inner corona, which is difficult for coronagraphs to observe because of scattered light and diffraction.
• Coronal Heating Problem: The corona can exceed 1 million°C, while the photosphere is about 5,500°C.
• Solar Magnetic Field: Coronal structures such as streamers reveal the magnetic processes driving solar activity and the 11-year solar cycle.
• Space Weather: The corona is the source region of solar wind and Coronal Mass Ejections (CMEs), which can affect satellites, GPS, communications and power grids.

Historical Significance

• Helium: During the 1868 total solar eclipse in India, Pierre Jules Janssen detected a previously unknown spectral line. Norman Lockyer subsequently identified and named the element helium after Helios, the Greek Sun god.
• General Relativity:Arthur Eddington’s 1919 eclipse observations provided important observational evidence for Einstein’s prediction that gravity bends light.

Why is it in the News?

A tiny "sungrazer" comet was discovered, photographed, and destroyed during the recent total solar eclipse — all within 24 hours.

What is a Sungrazing Comet?

• Sungrazing comets are a special class of comets that come very close to the sun at their nearest approach, a point called perihelion.
• To be considered a sungrazer, a comet needs to get within about 850,000 miles from the sun at perihelion.
• Many come even closer, even to within a few thousand miles.
• Being so close to the sun is very hard on comets for many reasons.
  • They are subjected to a lot of solar radiation which boils off their water or other volatiles.
  • The physical push of the radiation and the solar wind also help form the tails. As they get closer to the sun, the comets experience extremely strong tidal forces or gravitational stress.
  • In this hostile environment, many sungrazers do not survive their trip around the sun.
  • Although they don't crash into the solar surface, the sun can destroy them anyway.
• Many sungrazing comets follow a similar orbit, called the Kreutz Path, and collectively belong to a population called the Kreutz Group.
  • Close to 85% of the sungrazers seen by the SOHO satellite are on this orbital highway.
  • Scientists think one extremely large sungrazing comet broke up hundreds, or even thousands, of years ago, and the current comets on the Kreutz Path are the leftover fragments of it.
  • Comet Lovejoy, which reached perihelion on December 15, 2011, is the best-known recent Kreutz-group sungrazer.
  • And so far, it is the only one that NASA's solar-observing fleet has seen survive its trip around the sun.

What is a Comet?

• A comet is a small celestial body made primarily of ice, dust, and rocky material that orbits the sun in an elongated path.
• When a comet approaches the sun, the heat causes the ice to vaporize, releasing dust and gas into a glowing coma, or halo, around the comet's nucleus.
• This glowing coma often forms a tail that stretches away from the sun due to the solar wind and radiation pressure.
• Comets are often referred to as "dirty snowballs" or "icy dirtballs" because of their composition.
• They are believed to be remnants from the early formation of the solar system and carry important information about its history.
• Comets can have highly elliptical orbits, sometimes taking thousands or even millions of years to complete a single orbit around the sun.

Why is it in the News?

On Monday (April 8), a total solar eclipse will cross North America, passing over Mexico, the United States, and Canada. This type of solar eclipse is a rare event for any particular spot.

What is a Solar Eclipse?

• A solar eclipse takes place when the Moon moves in the middle of Earth and the Sun.
  • The Moon blocks the light of the Sun, either fully or partially, which casts a huge shadow on some parts of the world.

There are four different types of solar eclipses, including:

• Total solar eclipse: When the Moon blocks the Sun entirely, the areas in the center of the Moon’s shadow at the time witness a total solar eclipse.
  • The sky darkens and people who are in the path of a total solar eclipse can get a glimpse of the Sun’s corona — the outer atmosphere — which is usually not visible due to the bright face of the Sun.
• Annual solar eclipse: When the Moon passes in front of the Sun but is at or near the farthest point from Earth, an annular solar eclipse occurs.
  • In this scenario, the Moon covers the Sun in such a way that only the periphery of the Sun remains visible — looking like a ring of fire.
• Partial solar eclipse: A partial solar eclipse takes place when the Moon blocks just a part of the Sun, giving it a crescent shape.
  • During both partial and annular eclipses, the regions outside the area covered by the Moon’s umbra — the middle and the darkest part of the lunar shadow — will see a partial solar eclipse.
  • Partial solar eclipse is the most common type of solar eclipse.
• Hybrid solar eclipse: A hybrid solar eclipse — the rarest type of solar eclipse — is witnessed when an eclipse shifts between annular and total as the shadow of the Moon moves across the globe.
  • In this case, some parts of the world see a total solar eclipse, while others observe an annular solar eclipse.

How Often Does a Solar Eclipse Take Place?

• A solar eclipse is witnessed only during the new moon — when the Moon and Sun are aligned on the same side of Earth.
  • A new moon occurs about 29.5 days because that is how long it takes the Moon to orbit Earth.
  • This, however, does not mean that a solar eclipse happens every month. It takes place only between two to five times annually, because the Moon does not orbit Earth in the same plane as the Earth orbits the Sun.
• In fact, the Moon is tilted by about five degrees with respect to Earth.
  • As a result, most of the time when the Moon is in between the Sun and Earth, its shadow is either too high or too low to fall on the Earth.

Why is a Total Solar Eclipse so Rare?

• While there can be between two and five solar eclipses every year, total eclipses only happen about once every 18 months or so.
• This is because a total eclipse is only visible if one is standing in the umbra — the other part of the shadow is called the penumbra, which is not as dark as the umbra.
  • The umbral shadow is very small, covering only a small part of Earth.
• In fact, the entire path of the umbral shadow during a solar eclipse will only cover less than one percent of the globe.
  • This is why only very few people will get to see a total eclipse at a time.
• Moreover, about 70 percent of the globe is underwater and half of the land is considered uninhabited.
  • That’s why, it is quite rare when a total solar eclipse happens and a lot of people get to see it.

Umbra and Penumbra:

• During a solar eclipse, the Moon comes between the Earth and the Sun, casting a shadow on the Earth's surface.
• This shadow consists of two main parts: the umbra and the penumbra.
  • The umbra is the central, darkest part of a shadow, such as during a total solar eclipse when the Moon completely covers the Sun.
  • The penumbra is the outer part of the shadow where the obscuration is partial, resulting in a partial solar eclipse.