Wish You A Happy Astrnomy Day!

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Astronomy Day?

Astronomy Day is celebrated bi-annually, on the Saturday closest to the first Quarter Moon between April and May, and on the Saturday closest to the first Quarter Moon between September and October.

The First Quarter Moon during Spring this year is on the 8th of May and during Autumn, it is on the 2nd of Oct.

So Astronomy Days of 2022 are May 7th and Oct 1st

What is a Quarter Moon?

As the Moon revolves around the Earth on its orbit, it passes between the Earth and the Sun and moves behind the Earth, once every month. We all know that these 'phases' of Moon are called New Moon and Full Moon.

The phase when the Moon is exactly half-lit and occurs between the New Moon and the Full Moon is the First Quarter Moon, and the phase when the Moon is exactly half-lit and occurs between the Full Moon and the New Moon is the Last Quarter Moon.

Quarter Moons are fascinating to amateur astronomers because this phase is ideal to observe the Moon with a pair of binoculars or a small telescope. The Moon’s surface is illuminated at a very shallow angle. As a result, mountains and crater rims cast long shadows which makes them easily observable.

Did you know?

The planet Venus also has phases like our Moon. Yes! As Venus makes its way around the Sun, its orbit carries it between the Earth and the Sun. When it moves further in this orbit, the planet passes behind the Sun, as seen from the Earth. While in this orbital motion, the planet’s surface is lit by the Sun from various angles, causing the ‘Phases’ of the planet Venus. 🌙

Lord of the Rings, Loses his Rings...

Earth moves through the plane of Saturn’s rings once every 15 years. When this happens, one can look at Saturn through the telescope and perceive no rings! This is expected to occur on the 23rd of March, 2025.

Lord of the Rings also Floats!

Saturn is a gas giant that contains mostly Hydrogen, Helium, Oxygen and other elements in liquid and gaseous form, with a density of 0.687 grams per cubic centimetre. Water, on the other hand, has a density of 1 gram per cubic centimetre. This implies that if we could find a large enough pool and dropped Saturn into it, the Lord of the Rings would float.

Saturn is farthest of the planets visible to the naked eye under a moderately dark sky. Saturn is as almost as distant from Jupiter, as Earth is from Jupiter, with an orbit of radius 9 times the Earth-Sun orbital radius.

The Biggest Star!

The largest known star is Stephenson 2-18, with a radius that is 2150 times the radius of the Sun. The radius of the Sun is 695700km. Consequently, the radius of this star is 1495755000km. So if you replace the Sun with the star Stephenson 2-18, the outer layers of this massive star would outstretch upto Saturn’s Orbit!.

The Farthest Star known to Science

MACS J1149 Lensed Star 1, also known as Icarus, is a blue supergiant star located about 14 billion light years away from us. The  scientists used the Hubble Telescope, assisted by a gravitational lens, to spot this star, whose light travelled for 9 billion years before it reached us.

So, the light that was captured in the images left the star even before our Sun was born.

While you cannot see Icarus, you can see one of the closest Stars visible to the naked eye, this Month.

Rigil Kentarus : The closest visible star.

Rigil Kentarus, also known as Alpha Centauri, is the brightest star of Centaurus, visible in the southern skies in the evenings from May to September.

Around 8pm in the evening, look towards SSE direction (between south and south-east). The closest and the brightest star you see at the horizon is Alpha Centauri.

Rigil Kentaurus is a star just like our Sun, located 4.37 light years away.

This means that the light from this star, that you observe on this Astronomy Day, left the star 4 years, 4 months and 13 days ago. That was 2nd January 2017. Where were you on that Day?

Sun is not a Super Star!

All the stars you see in the night sky are bigger and brighter than the Sun. Alpha Centauri is slightly larger than the Sun.

This means that our Sun isn’t visible from any of these star systems except from the Alpha Centauri star system. From Alpha Centauri, at 4.37 light years, the Sun would appear in the constellation of Cassiopeia

Cassiopeia from another star system?

Would Cassiopeia appear the same way from other star systems? What if we travelled to a really far star system and took a glance at Cassiopeia?
Here’s a how the stars of Cassiopeia constellation would look in 3D Space….

Try This one:

Here's what Big Dipper , the Ladle, the Sapratishi Mandala... Looks like in 3D space, across light years:

Click and dragSwipe the spaceto explore in 3D