Expect to see a lot of red-orange landscapes over the next few weeks, as the Curiosity rover beams back its first photos of the rugged Martian scenery and space. But why is Mars red, anyway?
The simple explanation for the Red Planet’s color is that its regolith, or surface material, contains lots of iron oxide — the same compound that gives blood and rust their hue. But why does Mars have so much iron, why is that iron “oxidized,” and why does iron oxide look red?
It all started 4.5 billion years ago. When the solar system formed, many of the planets landed a dose of iron. Forged in the heart of long-dead stars, the heavy element swirled around in the cloud of gas and dust that gravitationally collapsed to form the sun and planets. Whereas the bulk of Earth’s iron sank to its core when the planet was young and molten, NASA scientists think Mars’ smaller size (and weaker gravity) allowed it to remain less differentiated. It does have an iron core, but abundant iron exists in its upper layers, also.
Plain-old iron looks shiny black. The element only takes on a reddish tinge when it has been exposed to oxygen, and enough oxygen at that for it to become iron(III) oxide, an atomic fivesome composed of two iron atoms and three oxygen atoms. So why did so much of the iron on Mars’ surface oxidize, or gang up with oxygen?
In fact, the jury’s still out on that one. For sure, some sort of weathering gradually rusted the iron on Mars. But did the ancient rainstorms that are thought to have occurred on a young, wet Mars rust the iron by pounding the regolith with oxygen atoms freed from water molecules? Or, did the oxidation happen gradually over billions of years, as sunlight broke down carbon dioxide and other molecules in the atmosphere, producing oxidants such as hydrogen peroxide and ozone? Or, as a group of Danish scientists suggested in 2009, have Martian dust storms slowly rusted the iron, by crumbling the quartz crystals that also exist in the regolith and leaving their oxygen-rich surfaces exposed?
Because no one yet knows the right explanation, the color of Mars is, in a sense, still a mystery. But however its surface rusted, the compound iron(III) oxide appears red because it absorbs the blue and green wavelengths of the light spectrum while reflecting the red wavelengths. [Your Color Red Could Be My Blue]
The planet’s bloody tinge — visible even from millions of miles away — got it strapped with the name of the Roman god of war, while other civilizations also named the planet for what was once its main distinguishing feature. The Egyptians called it “Her Desher,” meaning “the red one,” while ancient Chinese astronomers went with “the fire star.”
Mars is an extraordinary planet with mountains, pits, and caves like Earth. Through endless innovations in technology, we have learned a lot about this red planet. Find out 40 really interesting facts about Mars that you probably would’ve never guessed.
1. Mars is also known as the Red Planet.
2. The color of Mars is blood-red.
3. Mars is the fourth planet distanced from the Sun.
4. Galileo Galilei was the first scientist who discovered Mars.
5. The distance of Mars from the Sun is 227.9 million km.
6. The diameter of the Mars is 6,779 km.
7. Mars is less dense than the Earth.
8. Mars is the 2nd most hospitable planet in our solar system.
9. Mars’s core is surrounded by a silicate mantle.
10. Mars and Earth have approximately the same landmass.
11. Like Earth, Mars has seasons and similar rotational patterns.
12. Phobos & Deimos are the names of the two moons of Mars.
13. The surface temperature of Mars -153 to 20 °C
14. There have been around 40 missions to Mars, only 18 missions have been successful.
15. Mars has “Olympus Mons”, the tallest mountain in the solar system.
16. Out of 51, only 21 missions to Mars have been successful.
17. It would take around six Mars to fill the surface of the Earth.
18. The USA made the first successful mission to Mars in 1964.
19. It would cost nearly US$18,000 to post a letter to Mars.
20. Mars has less surface gravity as compared to Earth.
21. Mars has the biggest dust storms which last for months and covers the entire planet.
22. Mars had an ocean which covered 19% of its surface.
23. A year on Mars is 687 days and a day lasts 40 minutes more than one on Earth.
24. Mars’s soil is mainly fertile for growing asparagus.
25. On Mars the Sun appears about half the size as it does on Earth.
26. Mars takes its name from the Roman god of war.
27. The Sunset is blue On Mars.
28. Mars is much colder than Earth.
29. Mars is one of the brightest planets.
30. The diameter of Mars is about 53% of Earth’s, making it the second smallest planet in the solar system.
31. A year on Mars is 687 days but a day on the Red Planet only lasts 40 minutes more than one on Earth.
32. Mars consists exclusively of carbon dioxide.
33. Mars had water in the ancient past.
34. In 2003, Mars made its closest approach to Earth in nearly 60,000 years, coming within 34.8 million miles of our planet.
35. Mars has all four seasons.
36. Mars is populated by seven Robots.
37. The NASA’s Curiosity Rover sang the “Happy Birthday” on its one-year anniversary on Mars.
38. Over 100,000 people have applied for a trip to Mars.
39. Pieces Of Mars had fallen on Earth because of low gravity.
40. Mars has also both North and South polar ice caps.