What is Solar Debris?
- After birth of the Sun; debris was blown outwards
- Much of the debris eventually fell back into the Sun, if its trajectory was correct
- Other debris, has enough outward energy to break free of the Sun’s gravity, began to drift in orbit around the Sun
Comets & TNOs
- Comets: Dirty snowballs
- Made of dust trapped in water, carbon dioxide, methane and ammonia
- Consist of solid mass body called the Nucleus
- Most comets orbit BEYOND Neptune’s orbit in EDGEWORTH KUIPER BELT & OORT CLOUD
- 375 + large bodies (100s km in diameter) found in EK belt called TRANS NEPTUNIAN OBJECTS (TNOs)
- Some comets move close to sun in Elliptical orbits (visible in night sky)
Comet’s tail
- Once in Jupiter’s orbit- sun MELTS comet’s icy surface
- Forms: COMA
- Cloud of gas & dust that expands
- Solar winds push material into space, causing dramatic tails that may extend millions of kms
- As it moves away from sun, tail can PRECEDE comet
- At closest point to sun , they are as WIDE as Jupiter!
- (i.e Halley’s Comet: Returns every 76 years; named after Edmund Halley discovered the comet. Last one was in 1986, Next one would be in 2062
Asteroids
- Asteroids- solid rock like masses that are leftover material from solar system formation
- IRREGULARLY SHAPED as most are less than 1km in diameter and they have no gravity
- Thousands of asteroids in solar space; two largest are CERES and PALLAS (1000km)
- Asteroid Belt: Lies between Mars and Jupiter.
- Revolves in the same direction as the planets
- 65 million years ago, collisions led to the extinction of dinosaurs
- Ceres, is about the size of Texas.
- They can contain water, iron, silicates, gold, lead, and uranium.
- If Jupiter were further out in it’s orbit , the asteroid belt between Mars & Jupiter probably would’ve formed a Mercury-sized planet.
- Both of Mars’ moons, and at least 10 of Jupiter’s are probably captured asteroids.
- The first manned mission to deeper space may not be Mars – but to an asteroid.
- There’ve been at least 3 extinction events on Earth due to asteroid strikes.
- We’ve only had one probe ever to orbit & land on an asteroid – Eros, about the size of Manhattan Island.
- Asteroids have their own moons.
Meteoroids
- Meteoroid– Rock/ Icy fragments travelling in space.
- Different from asteroids because they are smaller in size (less than 100m in diameter).
- About 5 to 15 visible meteoroids per hour
- Estimates state around million to a billion enter Earth’s atmosphere but they are so small that burn/vaporize in the air.
Meteors
- Meteor are lights made by meteoroids as it passes through Earth’s atmosphere.
- Caused by friction between the rapidly moving meteoroid and the atmosphere.
- Meteor Shower: Large numbers of meteors that streak across the night sky in within a few hours.
- When earth passes through a comet’s tail; particles from the tail plunge through the atmosphere.
- Predictable since comets pass through Earth’s atmosphere at the same time each year.
- Perseid Meteor Shower
- Meteorites
- Meteorites- part of large meteoroids that survive trip through the atmosphere and strikes Earth’s surface
- 3 types of meteorites
- 94%= STONY (Earth’s dark igneous rock) Silicates
- 5%= IRON (Large crystals, little nickel)
- 1%= STONY- IRON (molten silicate with molten metal)
- Most meteorites found in Antarctic Cap
Impact Craters
- Bowl-shaped depression after meteor strikes the earth
- Oldest crater named VREDEFORT
- Rare, only 150 known
- Earth’s atmosphere burns most meteoroids before striking Earth’s surface
- Earth is geologically active, often covering the impact craters
- Ripples in Earth’s surface
- Reservoirs for oil & gas deposit
- Arizona’s Barringer Meteor Crater
- Formed 49,000 years ago
- Iron meteorite
- 45m in diameter
- Carter is 1200m
