Tuesday, February 24, 2015

The Surface of Venus

Venus and Earth are often called twins because they are similar in size, mass, density, composition and gravity. However, the similarities end there.

Venus is the hottest world in the solar system. Although Venus is not the planet closest to the sun, its dense atmosphere traps heat in a runaway version of the greenhouse effect that warms Earth.

Murky clouds shroud the secrets of Venus

Friday, February 20, 2015

Red Giant Sun: A New Habitable Zone

When the sun becomes a red giant, the simple calculation would put its equator out past Mars. All of the inner planets would be consumed.

However, as the Sun reaches this late stage in its stellar evolution, it loses a tremendous amount of mass through powerful stellar winds. As it grows, it loses mass, causing the planets to spiral outwards. So the question is, will the expanding Sun overtake the planets spiraling outwards, or will Earth (and maybe even Venus) escape its grasp.

Red Giant Diagram

Ordovician-Silurian Mass Extinction

The third largest extinction in Earth's history, the Ordovician-Silurian mass extinction had two peak dying times separated by hundreds of thousands of years. During the Ordovician, most life was in the sea, so it was sea creatures such as trilobites, brachiopods and graptolites that were drastically reduced in number. In all, some 85% of sea life was wiped out. An ice age has been blamed for the extinctions - a huge ice sheet in the southern hemisphere caused climate change and a fall in sea level, and messed with the chemistry of the oceans.

A diorama portraying the seas of the Ordovician Period (from the Exhibit Museum, University of Michigan)

Monday, February 16, 2015

What lies at the edge of the Universe?

Commonly asked question regarding the size of the Universe:

Does the Universe have an edge, beyond which there is nothing?

Galaxies extend as far as we can detect... with no sign of diminishing.There is no evidence that the universe has an edge. The part of the universe we can observe from Earth is filled more or less uniformly with galaxies extending in every direction as far as we can see - more than 10 billion light-years, or about 6 billion trillion miles. We know that the galaxies must extend much further than we can see, but we do not know whether the universe is infinite or not. When astronomers sometimes refer (carelessly!) to galaxies "near the edge of the universe," they are referring only to the edge of the OBSERVABLE universe - i.e., the part we can see.

Timeline of the Universe

Why can't we see the whole universe?

Saturday, February 14, 2015

Crystals at the Centre of the Earth

A Seismic Adventure

There's a giant crystal buried deep within the Earth, at the very center, more than 3,000 miles down. It may sound like the latest fantasy adventure game or a new Indiana Jones movie, but it happens to be what scientists discovered in 1995 with a sophisticated computer model of Earth's inner core. This remarkable finding, which offers plausible solutions to some perplexing geophysical puzzles, is transforming what Earth scientists think about the most remote part of our planet.

Friday, February 13, 2015

The Late Heavy Bombardment

About 4 to 3.8 billion years ago a period of intense comet and asteroid bombardment is thought to have peppered all the planets including the Earth. Many of the numerous craters found on the Moon and other bodies in the Solar System record this event.
One theory holds that a gravitational surge caused by the orbital interaction of Jupiter and Saturn sent Neptune careening into the ring of comets in the outer Solar System. The disrupted comets were sent in all directions and collided with the planets. These water-rich objects may have provided much of the water in the Earth's oceans.
The record of this event is all but lost on the Earth because our planet's tectonic plate system and active erosion ensure that the surface is constantly renewed.

Monday, February 9, 2015

Saturn: The Crown Jewel of the Solar System

Saturn is the sixth planet from the sun and the second largest planet in the solar system. Saturn was the Roman name for Cronus, the lord of the Titans in Greek mythology. Saturn is the root of the English word "Saturday."

Saturn is the farthest planet from Earth visible to the naked human eye, but it is through a telescope that the planet's most outstanding features can be seen: Saturn's rings. Although the other gas giants in the solar system — Jupiter, Uranus and Neptune — also have rings, those of Saturn are without a doubt the most extraordinary.

10 Interesting Facts About Saturn:

Sunday, February 8, 2015

Redefining the runt of the Solar System: Mercury

The smallest of the planets in the Solar System, Mercury is an interesting place. Incredibly dense due to its proportionately large core Mercury is thought to have been once a much larger planet. 

Mercury is the smallest planet — it is only slightly larger than Earth's moon. Since it has no significant atmosphere to stop impacts, the planet is pockmarked with craters. About 4 billion years ago, an asteroid roughly 60 miles (100 kilometers) wide struck Mercury with an impact equal to 1 trillion 1-megaton bombs, creating a vast impact crater roughly 960 miles (1,550 km) wide. Known as the Caloris Basin, this crater could hold the entire state of Texas. Another large impact may have helped create the planet’s odd spin. 

10 Important Facts About Mercury: