Related Concept Videos
01:23States of Water
Water exists in any one of the three classical states: solid (ice), liquid (water), and gas (steam or water vapor). The state of water depends on i) the intermolecular forces that draw molecules together and ii) the kinetic energy that leads to movements that pull them apart.
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
Water freezes when the intermolecular forces are greater than the kinetic energy. Unlike most other substances, water is less dense in its solid state than in its liquid state. This is because each water molecule can form...
01:00The Water Cycle
The Earth’s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, the cycling of water is extremely important to ecosystem dynamics.
02:06Conditions on Early Earth
Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
02:34Water and Mineral Acquisition
Specialized tissues in plant roots have evolved to capture water, minerals, and some ions from the soil. Roots exhibit a variety of branching patterns that facilitate this process. The outermost root cells have specialized structures called root hairs that increase the root surface, thus increasing soil contact. Water can passively cross into roots, as the concentration of water in the soil is higher than that of the root tissue. Minerals, in contrast, are actively transported into root cells.
01:24Acceleration due to Gravity on Other Planets
The gravitational acceleration of an object near the Earth's surface is called the acceleration due to gravity. It can be measured by conducting simple experiments on Earth. However, such an experiment is impossible to conduct on the surface of other planets.
Astronomical observations are thus used to measure the acceleration due to gravity on other planets. This can be determined by observing the effect of a planet's gravity on objects close to it. The crucial factor that helps in this...
Astronomical observations are thus used to measure the acceleration due to gravity on other planets. This can be determined by observing the effect of a planet's gravity on objects close to it. The crucial factor that helps in this...
01:24Origin of Cellular Life
The origin of life on Earth is a complex and enigmatic event rooted in ancient biochemical processes and geological conditions. Experimental evidence supports the hypothesis that life began with the spontaneous formation of organic molecules such as RNA nucleotides, amino acids, and lipids under early Earth conditions. Factors like volcanic activity, intense UV radiation, and a reducing atmosphere without free oxygen likely facilitated these reactions. Hydrothermal vents on the ocean floor are...
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PLANETARY SCIENCE: Beating Up on a Young Earth, and Possibly Life.
Science (New York, N.Y.)·2007
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Updated: Jul 7, 2026
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Conducting Miller-Urey Experiments
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PLANETARY SCIENCE: Making a Splash With a Hint of Mars Water.
Science (New York, N.Y.)
|September 5, 2007
Summary
New Mars findings suggest possible liquid water and life, based on crater gully images. However, some scientists propose alternative explanations that do not involve water or life.
Area of Science:
- Planetary Science
- Astrobiology
Background:
- Recent high-resolution images of Martian craters reveal gullies.
- These gullies have features resembling those formed by water on Earth.
Purpose of the Study:
- To investigate the origin of gullies observed in Martian craters.
- To assess the potential for liquid water and life on Mars.
Main Methods:
- Analysis of high-resolution imagery of Martian crater gullies.
Main Results:
- The images show muddy-looking gullies on crater walls.
- These features suggest the possibility of liquid water on or near the Martian surface.
Conclusions:
- The observed gullies may indicate the presence of subsurface water.
