Module 6: Our Solar System, and Our Universe. Flashcards
rotation
23hr and 56min
At what rate does the earth rotate the sun?
1000mph
Precession
The earth wobbles on its axis, this slowly changes tilt.
Revolution
The earth revolves around the sun on an elliptical path averaging 93 miles from star.
The Sun
Relatively small star – yellow dwarf, about 1.2 million miles in
diameter, large enough to hold 125 million Earth’s.
Solar Granules
– The convective cells
of the sun. Each granule, or localized
area of convection, is about the size
of Texas.
Sun spots –
Comparatively cooler areas of the sun’s surface – 11 year activity cycles. Caused by
anomalies in the sun’s magnetic field. Range in size from a few hundred miles to the size of Earth.
Can last for a few hours or as long as a month.
Solar prominence
large arcs of incandescent gas thrown outward hundreds of thousands of miles
from the chromosphere. These are usually short lived, and most of the ejected gasses are pulled
back in by the sun’s gravity.
Solar Flares and Coronal Mass Ejections –
23 year cycles - Sometimes the explosive nature of these
prominences blast material completely out of the sun and into space. These CME’s vastly increase
solar wind, and can bombard other celestial bodies with highly charged atomic particles moving at
over 600 miles per second. Only Earth’s magnetic field protects us from these hazards.
THE TERRESTRIAL
PLANETS
Mercury, Venus, Earth, Mars
Features of terrestrial planets
- Earth-like in size, composition and proximity to the sun but most similarities end there.
- Solid relatively thin crusts with molten mantle and metallic inner-core.
- Thin atmosphere, if any. Mercury has no atmosphere.
- Dense, containing large amounts of iron and nickel in the interior.
- Can have some level of mantle convection and a magnetic field (Earth has much mantle
convection and a strong magnetic field). - Characterized by lighter, less dense elements and compounds near the surface.
- Violent past of meteor, comet and asteroid impacts as evidenced by craters.
- All interior to the great asteroid belt between Mars and Jupiter.
Earth is the only habitable planet, though there has been much theorizing on the potential
for someday terraforming Mars. But at this point, it is beyond our capability to even get a
person there safely, much less transform a planet for human habitation.
Asteroid belt
90 million mile wide belt of rocky, icy material of widely variable size orbiting the sun
at about 293 million miles. Much of this material is made of the same elements that
compose the interior planets, leading scientists to hypothesize that perhaps the belt is
the remnant of a destroyed planet. The largest of these asteroids, Ceres, is about 600
miles in diameter.
Jovian Planets
Jupiter, Saturn, Uranus, Neptune
Features of Jovian Planets
Well over 100 times the mass of terrestrial planets – Jupiter is so large that every other planet in
the solar system could fit inside it. It has the volume of nearly 1000 Earths.
* Relatively small solid metallic cores, capped by very densely compacted metallic hydrogen, and
above that liquid hydrogen and helium surrounding the core.
* Also an incredibly thick gaseous atmosphere containing hydrogen, helium, methane, ammonia
and water vapor.
* Were able to form as a result of weak solar heating. This allowed these planets to accumulate
lighter materials that were less affected by the sun’s gravity and frigid temperatures combined
with high pressures near the planets core converted these to chemical ices.
* Characterized by long revolutions. Extreme distance from the sun means o long orbital path.
* Characterized by rings of orbiting ice and debris.
* Strong gravitational fields can hold many satellites in orbit as it overpowers the escape velocity
of passing asteroids and planetesimals.
Kuiper belt
Asteroid belt on the outer edges of solar system
