Mars is often called the ‘Red Planet’ for plain reasons. But what gives our neighboring planet this distinct hue? While Earth is sometimes referred to as the ‘blue marble’ because it’s mostly covered in oceans and has a thick atmosphere giving it a blue appearance, Mars is covered in lots of iron oxide. These are the same compounds that give blood or rust their dicolorive colour. In light of this, it’s no coincidence that Mars, which on occasions can be seen as a bright red ‘star’, was named after the Greek god of war.
It’s not entirely clear how all that iron oxide wound up on the planet’s surface, but one thing’s for sure: it all started some 4.5 billion years ago when debris, gas, and dust began coalescing into planets. Among these materials was lots of iron, forged in the heart of long-dead stars.
Earth and Mars both have a lot of iron, but while the heavy element sank to Earth’s core when the planet was still young and mushy, scientists think iron was less homogenously incorporated into Mars due to its weaker gravity and smaller size. That’s not to say Mars doesn’t have an iron core too, but there’s still a lot of the metal in the upper crust to be found.
Yet, iron by itself isn’t red — it’s silvery all the way to shiny black. What happened is that all of this surface iron became oxidized, forming iron oxide or rust — a compound made of two iron atoms and three oxygen atoms. But how come so much of Mars’ surface iron got oxidized? Here’s where scientists are still not out yet, but there’s reason to believe this massive oxidation happened when Mars had flowing waterand a thick atmosphere, possibly not too different to what we have on Earth today. Leaving an iron-rich pot or spoon outside or in water for a lot of time will make it rust. A very similar process covered Mars in iron oxide.
An alternate theory, first proposed by Albert Yen of NASA’s Jet Propulsion Laboratory and based on data gathered by the 1997 Pathfinder mission, says a great deal of that iron oxide comes from meteorites.
In 2009, Danish researchers performed a study which found water isn’t necessary to produce a lot of iron oxide. Instead, crumbling quartz crystals — the kind found in the Martian regolith — leaves oxygen-rich surfaces exposed. This could easily have happened during the Martian dust storms which are so intense they sometimes kick up so much dust that can be seen with telescopes on Earth. Sunlight can also break down carbon dioxide and other molecules from the atmosphere producing oxidants like hydrogen peroxide and ozone.
Not the whole planet is red, though. Some regions look bright red, while others will appear even black because not everything is covered in iron oxide dust. Thanks to the rovers NASA landed on the planet, like Opportunity, Spirit, or Curiosity, the latest to touch down, we now have unprecedented views from Mars’ surface, but also of its sub surface. When the Phoenix Lander drilled just a few centimeters below the iron oxide rich surface, the ground was brown.
Here on Earth, the sky appears blue because of a physical phenomenon called Raleigh scattering. Because shorter wavelengths of light like violet and blue are scattered more by the molecules in the atmosphere, the blue photons appear to come from all directions. On Mars, the opposite is true as the dust that litters the planet’s light atmosphere scatters red photons, making the sky red. This can also happen on Earth when the air is heavily polluted or covered in smoke.
Oddly enough, sunsets on Mars appear blue.
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அன்பு நிறை மாயோன் அவர்களுக்கு(1)தமிழர் தன கண்ணால் காண்பவையை அவர்கள் மனதில் பட்டபடி பெயரிட்டு குறிப்பர் எடுத்துக்காட்டாக : புதிதாக உருண்டு திரண்ட கிழங்கு ஒன்றினை கண்ட ஒருவர் அதனை உருளைக்கிழங்கு என விளித்தான் அதுபோல் சிவந்து காணும் கோளினைசெவ்வாய் என பெயரிட்டனர் எனலாம். தமிழர் மட்டுமல்ல மற்ற எல்லா இனத்தாரும்கூட அப்படித்தான் செய்திருப்பார்கள்.
(2)8 + 10 + 18 = 36 சங்கநூல்களைத்தேடினேன் மேலும் என்னிடம் உள்ள நூற்களை எல்லாம் தேடி கண்டது முதல் முதலில் செவ்வாய்க்கோள் C 650 CE சார்ந்த திரு ஞசம்பந்தர் தன கோளாறு பாதிக்கத்தில்தான் செவ்வாய் கோளினைக் குறிக்கின்றார் எனக் கண்டேன் பல நூற்றுக்கணக்கானபிற்கால நூலைகளிலும் எனக்குசெவ்வாய்கே கோள் பற்றிக் கிடைக்கவில்லை ஆனால் என்னிடம் உள்ள 18 நிகண்டுகளில் செவ்வாய் கோள் பற்றி பற்பல பெயர்கள் உள்ளன . சேய் அங்காரகன் குசன், நிலமகன் என பல மாற்றுப்பெயர்களும் காட்டுகின்றன