The Vapor Cone.

A vapor cone, also known as shock collar or shock egg, is a visible cloud of condensed water which can sometimes form around an object. A vapor cone is typically observed as an aircraft, or object, flying at Transonic speeds. ( slightly slower than the speed of sound) 

The Pressure – Temperature dependence.

As the aircraft approaches the speed of sound, the air pressure around the object drops, and thereby the air temperature drops. If the temperature drops below the dew point, water in the atmosphere condenses to form a cloud in the shape of the shockwave.

Red Bull Stratos and the Vapor Cone.

Remember that epic jump where Felix Baumgartner, as a part of the Red Bull Stratos project broke the sound barrier ( reached Mach 1.25 ) during his descent? But why weren’t vapor cones seen around Felix’s body? Or were they?

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Vapor cones are formed only near the ground, where plenty of wet air persists. But when Felix broke the sound barrier, there was no wet air that surrounded him that would enable the formation of Vapor cones.

Have a Good day!

PC: twistedsifter

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Comets have two tails.

There are two types of comet tails: dust and gas ion.

A dust tail contains small, solid particles that are about the same size found in cigarette smoke. This tail forms because sunlight pushes on these small particles, gently shoving them away from the comet’s nucleus. Because the pressure from sunlight is relatively weak, the dust particles end up forming a diffuse, curved tail.

A gas ion tail forms when ultraviolet sunlight rips one or more electrons from gas atoms in the coma, making them into ions (a process called ionization). The solar wind then carries these ions straight outward away from the Sun. The resulting tail is straighter and narrower. Both types of tails may extend millions of kilometers into space. As a comet heads away from the Sun, its tail dissipates, its coma disappears, and the matter contained in its nucleus freezes into a rock-like material.

Comets don’t like the sun.

Comets lose a lot of mass when they go by the Sun. A lot: some shed hundreds of tons of material per second.
That’s actually a small fraction of the mass of a comet, but given
time, and lots of solar passes, it adds up. Every comet we see is slowly
dissolving in space. Eventually even the mighty Comet Halley will be
gone, broken down into a swarm of rocks, gravel, and dust once its gas
is gone.

Was the Supermoon a ‘Blue Moon’?

The phrase “Once in a blue moon” has nothing to do with the actual color of the moon! When 13 full moons occur in a year, usually one calendar month has two full moons; the second one is called a “blue moon”. 

So, the Supermoon was not a Blue Moon. But July experienced two full moons- one on 2 and 31 respectively. The full moon on July 31 was termed a ‘Blue Moon’,

Blue Moons are a rarity.The next Blue Moon is set to occur on Janauary 31, 2018!! ( I guess, that explains the origin of the phrase ) 

Can the moon ever be blue?

Famously, after the eruption of Krakatoa in 1883, the moon appeared Blue for nearly two years! This is attributed to the scattering of light due to the tiny particles of dust that are reminiscent from a Volcano eruption or from Forest fires.

Hope you guys had a good time 🙂

PC: earthsky, snowbasin

Parts of a day!

whatdidulearntoday:

I was under the impression that there were only 4 parts to day- morning, afternoon, evening and night. It blew my mind when i found out that technically there are ten parts to it!.

1.Dawn

The first appearance of light ( very weak light ) in the sky.

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2.Twilight

It is the time between Dawn and Sunrise.

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3.Sunrise

The instant at which the upper edge of the Sun appears over the eastern horizon in the morning.

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4.Morning.

Morning is the period of time between dawn and noon ( 12 ‘o’ clock in the daytime).

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5.Daylight.

Constitutes all the time that the sun is right above our heads.

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6.Evening.

The period of the day between late afternoon and night.

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7.Sunset

The time of sunset is defined in astronomy as the moment when the trailing edge of the Sun’s disk disappears below the horizon.

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8. Twilight

The time between Sunset and Dusk.

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9.Dusk.

Dusk is the darkest stage of twilight in the evening.

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10.Night.

The complete absence of direct sunlight. (Since moon light is a form of indirect sunlight )

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Mother Nature’s Irony!

More pollutants we dump into the atmosphere, the colorful the skies get! The dramatic photographs captured after a volcanic eruption are an example of this ironical fact.

This is so because when more number of particles(pollutants) are present in the atmosphere, a greater spectrum of light gets scattered. This results in the dazzling display of colors that you witness in the sky. This phenomenon is known as Rayleigh scattering.

In the past, there have been a couple of posts which dealt with Rayleigh scattering, you can find them all here. 

Have a great Weekend!

PC: whybecausescience,reddit.