Curiosity: Update 3 – H2O Traces on Mars

Ancient Martian Stream, Bedrock

On September 27, 2012, the rover Curiosity (Mars Science Laboratory) snapped and sent back images of Martian bedrock possibly once home to a fast-moving stream. Curiosity founded rounded pebbles, probably due to erosion by water. The rocks ranging in size from sand grains to golf balls could not have been carried into the Gale Crater by wind, but carried water for a 20 to 25 miles and smoothed out. At one point in the past lasting thousands to millions of years, Mars may have been overflowing with liquid water, but present-day Mars is a barren desert with nothing but remnants of rock carved by water. Curiosity made this remarkable discovery when driving to Glenelg, the point where three types of terrain meet. Finding water is only the first step to discovering a once-habitable environment for microbial life. However, the dried-up stream didn’t preserve organic carbon. Carbon is necessary for life, so Curiosity will head to the foothills of Mount Sharp to find organic materials. Instead of “following the water,” scientists will now “follow the carbon.”

References

” Curiosity finds signs of ancient stream on Mars.” FOX News. Fox News, 27 Sep 2012. Web. 27 Sep 2012.

Kaufman, Mark. “Curiosity rover’s Mars landing site was once covered with fast-moving water, NASA says.” The Washington Post. The Washington Post, 27 Sep 2012. Web. 27 Sep 2012.

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The 8 Planets – Part 4: Mars

NEXT STOP: MARS!

Mars

A very belligerent planet. Mars. Named after the Roman god of war, Mars appears as a fiery battle-stained planet. Out of the seven planets (excluding Earth), Mars seems to be the most habitable planet. Although much smaller than Earth, Mars has an atmosphere (though thinner), ice caps (though mainly dry ice, or frozen carbon dioxide), and evidence that water once flowed on its surface. Astronomers have yet to find life on Mars, but sci-fi authors have long contemplated the possibility of life on Mars in the present or future (e.g. The Martian Chronicles). Don’t let the name fool you. Mars, the god of war, leaves no one alive while Venus, the goddess of love, often has a soft heart. In the solar system, Venus is a deadly planet while Mars is relatively benign.

The fourth planet from the Sun and the last terrestrial planet, Mars, the “Red Planet,” is actually the second smallest planet and the most explored aside from Earth. Distinguishable by its red color from an abundance of iron oxide, Mars has a thin atmosphere blanketing a surface filled with impact craters, volcanoes, valleys, deserts, and polar ice caps. Mars is also home to Olympus Mons, the tallest mountain in the solar system, and Valles Marineris, a large crack on Mars’ surface and one of the largest canyons. Dark patches on its surface suggest presence of large quantities of liquid water in the past. Though similar to Earth in surface features and climate, Mars is only about half the size of Earth, with 15% of Earth’s volume and 11% of mass. Because of its similar axial tilt, Mars has Earth-like seasons, though with a colder climate. Barren, Mars has the largest dust storms in the solar system. Mars is bigger than Mercury but less dense because of an iron sulfide core composed of lighter elements. The core is surrounded by a silicate mantle and the mantle by a thick crust. With no evidence of a global magnetic field, Mars, however, has some magnetized crust that has reversed polarity like Earth’s ocean floors. Mars’ geological history is split into three periods: Noachian period (4.5 – 3.5 billion years ago, oldest surfaces with impact craters and extensive flooding of water), Hesperian period (3.5 to 2.9 – 3.3 billion years ago, extensive lava plains), Amazonian period (2.9 – 3.3 billion years ago to present, few impact craters, Olympus Mons forms, lava flows). On Martian Soil, light silica-rich streaks appear on steep slopes, perhaps the dark underlying layers of soil exposed after dust avalanches. As Earth speeds Mars, Mars appears to move in a retrograde motion, or backwards with respect to the stars. Mars has two moons: Phobos and Deimos.

PHOBOS and DEIMOS

Phobos and Deimos

Mars’ two moons look more like asteroids than Earth’s moon. Named for Mars’ sons and attendants in battle, Phobos and Deimos mean “fear” and “panic,” respectively. Because of their low albedo, carbonaceous chondrite composition, and irregular shapes, scientists have proposed the capture theory. Stray asteroids from the Trojan belt may have been pulled into Mars orbit. Phobos is below synchronous position, so Mars’ tidal forces will eventually cause Phobos to crash into Mars’ surface, either forming an impact crater or a dust ring in 50 million years. On the contrary, Deimos is outside synchronous position, so the moon is slowly spiraling away from Mars. In about 50 million years, Mars may have no moons!

MISSIONS*: Mariner, Mars, Viking, Mars Global Surveyor, Mars Pathfinder, Mars Odyssey, Mars Express, Spirit, Opportunity, Rosetta, Mars Reconnaissance Orbiter, Phoenix, Dawn, Mars Science Laboratory

* Successful Missions

OVERVIEW

  • Order in Solar System: #4
  • Number of Moons: 2
  • Orbital Period: 687 days
  • Rotational Period: 24 hours, 39 minutes, 35 seconds
  • Mass: 6.4185 x 10^23 kg (0.107 Earths)
  • Volume: 1.6318 x 10^11 km³ (0.151 Earths)
  • Radius: 3,396 km (0.533 Earths)
  • Surface Area: 1.45 x 10^8 km² (0.284 Earths)
  • Density: 3.9335 g/cm
  • Surface Pressure: 0.636 kPa
  • Eccentricity of Orbit: 0.093315
  • Surface Temperature (Average): 210 K
  • Escape Velocity: 5.027 km/s
  • Apparent Magnitude: +1.6 to -3.0

The 8 Planets – Part 3: Earth

NEXT STOP: EARTH!

Earth, our home planet

Imagine a blank sphere floating in the middle of space. Now picture the whole sphere flooded by blue oceans, rivers, and lakes. And seven continents, defined by low elevation green patches, high elevation brown areas, and deserts golden brown. Add white ice caps capping the North and South Poles. And white swirling clouds in the atmosphere. Then tilt the whole sphere 23.5 degrees. There. Our home planet, Earth!

Third planet from the Sun and the only planet to support life, Earth, or the Blue Planet, formed 4.54 billion years ago from accretion of the solar nebula and first hosted life approximately 1 billion years ago. Though technically not named after any Gods, the Greek god Gaea is mother of the earth. Home to millions of species, Earth has the “Goldilocks Phenomenon” since all conditions including climate and temperature support life. Earth is in the “life zone,” where water exists in all three phases: gas, liquid, and solid. Earth’s surface is 30% land and 70% water. Collectively, the biosphere and the abundance of minerals support life. Earth’s atmosphere, specifically the ozone layer, and magnetic field blocks high-energy electromagnetic radiation harmful for life. The axis of the Blue Marble, the largest terrestrial planet, tilts 23.5 degrees, causing the four annual seasons. The hemisphere tilting toward the Sun is in summer and the other is in winter. In fact, Earth’s orbit is nearly circular and Earth is actually closer to the Sun in winter than in summer. Earth’s tectonic activity, or the sliding of tectonic plates, causes volcanic activity and earthquakes that renew Earth’s surface. A viscous liquid mantle and a rigid crust surround a solid core. Earth orbits the Sun once every 365.25 days and rotates once every 24 hours. Earth has one moon, or natural satellite.

THE MOON

The Moon

Earth only has one moon, called the Moon. Reflecting sun light, this natural satellite orbits the Earth once every ~29 days, seen in different phases throughout every month: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, Waning Crescent. Formed about 4.53 billion years ago, the Moon is an imperfect sphere bombarded by asteroids and comets during the Late Bombardment Period 3.8-4.1 billion years ago. In fact, the Near Side is much smoother than the Far Side (never observed from Earth), so one theory is that the Moon was actually two chunks of material that collided. However, the giant impact hypothesis indicates that a large object collided into Earth’s surface and while some mass fused with Earth, the rest formed the Moon. This theory explains why the Moon’s interior is similar to that of Earth. The Moon’s gravitational pull contributes the movement of ocean tides, stabilizes Earth’s tilt, and gradually slows the Earth’s rotation.

OVERVIEW

  • Order in Solar System: #3
  • Number of Moons: 1
  • Orbital Period: 1 year
  • Rotational Period: 1 day
  • Mass: 2.9736 x 10^24 kg
  • Volume: 1.08321 x 10^12 km³
  • Radius: 6,371 km
  • Surface Area: 5.10 x 10^8 km²
  • Density: 5.515 g/cm
  • Surface Pressure: 101.325 kPa
  • Eccentricity of Orbit: 0.0167
  • Surface Temperature (Average): 287.2 K
  • Escape Velocity: 11.186 km/s
  • Apparent Magnitude: N/A