Two solar eclipses await astronomy enthusiasts in 2021.
The first is an annular solar eclipse, which is not one that happens every year! Instead, the word annular is derived from annulus, or ring-shaped. The Moon isn’t large enough to cover the entire sun, so it appears to form a hole in the center of it, leaving a ‘wedding band’ in the sky.
The second solar eclipse of 2021, at the end of the year, is the classic total solar eclipse. In this one, the Moon will completely hide the solar surface, revealing the Sun’s corona and making stars visible in the day.
This article will guide you through why a solar eclipse occurs in the first place, why they aren’t visible across the entire planet, and what you can expect while chasing the 2021 eclipses.
What is a Solar Eclipse?
Solar eclipses are proof that daytime astronomical events can be as beautiful as the night ones. They occur when the Moon’s orbit places it precisely between Earth and the Sun, an alignment called syzygy (pronounced SIZ-eh-gee).
In doing so, the Moon blocks the sunlight, casting a shadow on Earth. If you’re standing in that shadow, you’ll see the Sun obscured to a greater or lesser extent.
Solar eclipses, where the Moon completely covers the Sun, happen due to a perfect coincidence of size and distance.
The Moon is 400x smaller than the Sun but is also 400x closer to Earth. This serendipity makes the lunar disc exactly the same size as the solar one from our perspective.
A solar eclipse begins when the moon makes its first contact, touching a limb of the sun and seeming to take a bite out of the perfect solar circle of light.
When the Sun is not totally covered, the eclipse is a partial one. As the partial eclipse progresses, the bite taken out of the Sun by the Moon grows gradually until the Sun is only a narrow crescent in the sky.
Ten-to-fifteen minutes before totality occurs is when the environment around you begins to change dramatically. There is a noticeable drop in brightness, the shadows grow sharper on the ground, and the sunlight will look strangely different, almost like you’re wearing shades.
A few seconds before the moment of totality, the last vestiges of sunlight peep through valleys between mountains on the Moon, causing the light to break into a thin string of beads, called Baily’s beads.
When totality hits, we instantly see our first glimpse of Sun’s corona, leading to the famous diamond ring effect. This is the stage where darkness takes hold too, making the brighter stars and planets visible in the daytime.
While the entire eclipse, from first to the last contact, lasts anywhere between one to three hours, totality itself lasts only for 2-5 minutes.
All too soon Baily’s beads and the diamond ring will be visible once again as the moon begins to uncover the sun and the total solar eclipse reverts to a partial solar eclipse.
The disc of the Sun fattens once more as the Moon moves past and the eclipse comes to an end as the Moon’s limb touches the Sun’s in the final act of a solar eclipse, known as last contact.
Why is a Solar Eclipse Not Visible Across the Whole Planet?
The Moon’s shadow is only a few hundred miles across, which is nowhere near large enough to cover the entire Earth. This underlines the fact that you are very fortunate to observe a total Solar eclipse because the strip of Earth they can be seen from is so small.
Furthermore, the fact that only a tiny part of the Earth’s surface experiences an eclipse makes it extremely rare the same place will see a second eclipse within a human lifetime.
The Sun, Moon, and Earth are in constant motion in slightly elliptical orbits. Earth rotates around its axis while the Moon orbits the Earth, and their geometry changes with every eclipse, making it very rare for the same point on the surface of our planet to see consecutive solar eclipses.
What’s The Difference Between The Umbra and Penumbra?
In every eclipse that occurs, there are two shadows cast by the Moon, the inner, darker umbra, and the outer, lighter, penumbra.
It’s easiest to think of the umbra as the shadow we see when the whole Sun is covered, while the penumbra is the shadow caused by a partial covering of the Sun.
As you might imagine, the penumbra has different darkness levels. The part of the penumbra closest to the umbra, where the Sun’s surface might be >90% obscured, is much darker than at its far edge where the Sun is less than 10% covered.
If you stand inside the path of the umbra – also known as the path of totality – the Sun will be entirely blocked by the Moon and you’ll observe a total eclipse.
However, if you stand inside the penumbra during an eclipse, you will only observe it as a partial eclipse.
Of course, some solar eclipses are only partial. When this happens, there is no umbral shadow hitting the Earth’s surface.
Solar Eclipses 2021
There are only two solar eclipses in 2021, with the details set out below.
Annular Solar Eclipse | June 10, 2021
- Partial eclipse: North of North America, Europe, Asia
- Annular eclipse: Northern and eastern Canada, Greenland and Russia
The first solar eclipse of the year will be an annular one that lasts from 8:12 UT to 13:11 UT on June 10, 2021.
This eclipse will last for only 3 minutes 51 seconds and will cover 94% of the Sun. The Moon is not large enough to cover the entire sun because it will be just 2 days past apogee (furthest from Earth), and will thus be 6.7% smaller than average.
Because of this, the Sun’s disk will be visible at the eclipse’s maximum point, and neither the Sun’s corona nor the diamond ring can be seen.
However, the outer edges of the Sun will be visible all this while, forming the famous ‘ring of fire’.
The annular eclipse will be visible from Canada, Greenland, and Russia. The path of annularity (shown as the red dot in the gif below) will cross over the North Pole, (the only eclipse to do so in the 21st century) and then move south.
Viewers in the northeastern United States will see a partial solar eclipse.
June 10, 2021 – Annular Solar Eclipse Timings
- Partial Eclipse Begins: 08:12:15 UTI
- Annular Eclipse Begins: 09:49:43 UTI
- Maximum Eclipse: 10:41:51 UTI
- Annular Eclipse Ends: 11:33:45 UTI
- Partial Eclipse Ends: 13:11:16 UTI
Total Solar Eclipse | December 04, 2021
- Partial eclipse: South Africa and South Atlantic
- Total eclipse: Antarctica
2021’s only total solar eclipse, which will unusually move from east to west over west Antarctica, will only be visible in that region from 5:29 UT to 9:37 UT.
This eclipse occurs 0.1 days before the Moon reaches perigee (the closest to Earth), causing it to be 5.6% bigger than average.
The Moon’s large size will cover the sun’s disk entirely, called the totality, for 1 minute 54 seconds. The path of totality is shown by the black ‘smudge’ in the gif below.
December 04, 2021 – Total Solar Eclipse Timings
- Partial Eclipse Begins: 05:29:11 UTI
- Annular Eclipse Begins: 07:00:01 UTI
- Maximum Eclipse: 07:33:22 UTI
- Annular Eclipse Ends: 08:06:29 UTI
- Partial Eclipse Ends: 09:37:24 UTI
Future Solar Eclipses
This table shows all the upcoming total and partial solar eclipses for the rest of the decade. We will, of course, bring much more detail on each one nearer the time.
|10 Jun 2021||Europe, Asia, Canada and northern USA||Annular|
|4 Dec 2021||South Australia, south Africa, and Antarctica||Total|
|30 Apr 2022||Southwest South America, Antractica||Partial|
|25 Oct 2022||Europe, southwest Asia, northeast Africa||Partial|
|20 Apr 2023||Southeast Asia, Australia, Antarctica||Total|
|14 Oct 2023||North and South America||Annular|
|8 Apr 2024||Western UK, North America, northern South America||Total|
|2 Oct 2024||Southern South America||Annular|
|29 Mar 2025||Northwest Europe, Greenland and northeast Canada, northwest Africa||Partial|
|21 Sep 2025||New Zealand and southeastern Australia, Antarctica||Partial|
|17 Feb 2026||Southeast Africa, southern tip of South America, Antarctica||Annular|
|12 Aug 2026||Much of Europe, north USA and Canada, northeast Asia, northwest Africa||Total|
|6 Feb 2027||South America and western Africa||Annular|
|2 Aug 2027||Southwest Europe, southwest Asia, northern Africa, eastern Canada||Total|
|26 Jan 2028||North and South America, western Europe, and western Africa||Annular|
|22 Jul 2028||Australia, New Zealand, southern Asia||Total|
|14 Jan 2029||North America||Partial|
|12 Jun 2029||Northern Asia and northern Canada||Partial|
|11 Jul 2029||Southern South America||Partial|
|5 Dec 2029||Southern South America and Antarctica||Partial|
|1 Jun 2030||North Africa, Europe, Asia||Annular|
|25 Nov 2030||Southern Africa, Australia, southern Asia||Total|
While this post is meant to equip you with knowledge of when the eclipses occur, you cannot completely prepare for the splendor of these cosmic coincidences.
Eclipses give you a chance to watch the solar system at work right in front of your eyes; of the Moon around Earth and Earth around the Sun.
Irrespective of how many times you have seen it, the awe when an eclipse begins, the regret when it ends all too soon, and the ecstasy of witnessing it all cannot be jammed into strings of words. You can only experience it and store the bittersweet memory till the next one comes rolling in.
Written by Sharmila Kuthuner