EVERYTHING YOU DIDN‘T NOT WANT TO

KNOW ABOUT NEPTUNE

KATIE HUGHES

DISCOVERYIT WAS AN ACCIDENT! I SWEAR!

SOMETHING’S NOT RIGHT WITH THIS PICTURE

• 1781, Uranus was discovered

• It did not follow the path that was predicted by Newton’s and Kepler’s Laws

• Either the laws were wrong

OR

• There was another body there

EUROPEANS BECOME PSYCHIC

John Adams Urbain Le Verrier

• Adams and Le Verrier predicted the same location for the mystery planet, independently

English Mathematician

French Astronomer

JOHANN GALLE• In 1846, Galle located Neptune within

a degree of where it had to be in order to have an observed influence on Uranus

He looks like George W Bush…just saying…

THE PLANETIT’S NOT A ROMAN GOD

BACK TO THE BASICS:• Smallest of the four gas giants

• 3.88 times Earth’s diameter

• 17.1 times Earth’s mass

• Density of 1640 kg/m^3

• Coldest of the four gas giants

• Takes 164.8 Earth years to orbit the sun

• 30 time farther from the sun than the Earth

• Cloud features can easily be seen

• Still effected by the sun’s heat and has seasons

FIRST SIGHTS: VOYAGER 2• August 1989, it captured a detailed

close up picture and a wealth of data on Neptune

THE ORBIT• Aphelion: 2.88 billion miles

• Perihelion: 2.76 billion miles

• Orbit is elliptical but less so than others• There is no marked difference between the aphelion and the perihelion

• Only Venus has a more circular orbit

THE ORBIT• 16.11 hours for one rotation

• The rotation axis is tilted by 28.3 degrees

• This creates an equatorial bulge

THE LAYERS• (1) Atmosphere of hydrogen, helium, and methane gases

• (2) Layer of water, methane, and ammonia ices

• (3) Rocky core surrounded by ammonia- and methane-laden water

• Note: there is not a solid surface

1

2

3

WATER MAKES MAGNATES• The magnetic field has an axis tilt of 46.8 degrees

• The axis does not go through the center of the planet

• 40% of Earth’s magnetic field

• The magnetic field is believed to originate from the second layer

How?

• The ammonia dissolves into the water and lose electrons

• The ions move with the rotating planet

• Creates a dynamo effect

• Creates a magnetic field

THE ATMOSPHERE• The atmosphere is the visible surface

• 79% hydrogen

• 18% Helium

• 3% Methane and trace gases

• The methane give the planet it’s blue color• Absorbs red and reflects blue

THE ATMOSPHERE

• Colossal storms and harsh winds

• Winds are worse around the equatorial region

• Winds blow at about 1340 mph

• Clouds are made out of methane ice crystals

• Cloud covers formed when the heated atmosphere rises then condenses

THE SEASONS

• Ground-based telescopes and Hubble show that the southern hemisphere has grown brighter since 1980

• Observed increase in the amount, width and brightness of banded cloud features

• 2003: Hubble sees seasonal changed near the poles

• 40 years of spring will lead back into summer

• The sun is not enough to drive the weather so the atmosphere may be warmed by an internal heat source

• Cloud top temperature: -320 F

THE GREAT DARK SPOT• Half as large as Jupiter’s Great Red Spot

• Same latitude and proportion as Great Red Spot

• It is about the same length as the Earth

• In 1994, it disappeared and reappeared in opposite hemisphere in April 1995

• Basically it likes to play hide n’ seek

Scooter

THE RING SYSTEMYOU ALMOST CAN’T SEE THEM

FIRST FINDINGS• First indication that there was rings was in 1980s

• Stars seemed to blink near the planet’s disk

• Voyager 2 discovered that the outer ring system was so thin that I couldn’t dim starlight

HOW DID THIS HAPPEN?• Rings retain methane ice

• It is believed that eons of radiation damage has converted the methane ice into darkish carbon compounds

• This accounts for the low reflectivity of the rings

THE SYSTEM ITSELF• Three dense regions that dim light

• There are six regions

• 5 regions are complete

• One remains unnamed

• If the material came together into a ball, it would only be a few miles wide

• The material is believed to come from near by moons

THE MOONSNOTE: WE WERE TOO LAZY TO ACTUALLY NAME ALL OF THEM WHEN WE FOUND THEM

JUST A HEADS UP

• There are couple of moons that will NOT be discussed

• Naiad (September 1989)

• Thalassa (September 1989)

• Despina (July 1989)

• Psamathe (2003)

• Neso (August 14, 2002)

• Laomedeia (August 13, 2002)

• Sao (August 14, 2002)

• S/2004 N1

FUN FACTS• 14 known moons

• 12 have irregular shapes and irregular orbits

• Suggests that Neptune captured them

• 4 of the 14 are within the ring system

• 6 of the inner moons were discovered using Voyager 2’s data

A FORMER SEA GOD• Proteus was discovered in June 16, 1989 by Stephen P. Synnott

• Almost equatorial orbit

• Extensive cratering

• First of the inner moons to be discovered

• Reflects six percent of the sunlight that hits it

THE LOVER• Larissa was discovered in  May 24, 1981 by David J. Tholen

• Larissa was originally thought to be a ring system

• Voyager 2 showed that it was just a irregular shaped moon

• 134 miles long

THE SEA NYMPH• Nereid was found on May 1, 1949 by Gerard Kuiper while he

was at the McDonald Observatory

• Highly eccentric and inclined orbit

• 5.9 million miles at its farthest

• 507,500 miles at its closest

YET ANOTHER SEA NYMPH• Galatea was discovered July 1989 by Stephen P. Synnott

• Galatea prevents the material in the Adams ring from spreading uniformly

THIS IS WHEN WE GET LAZY• S/2002 N1 was discovered on January 13, 2003

• Found by a team of astronomers trying to find out more about Neptune’s moons

• Has a highly inclined and elliptical orbit

• Now called Halimede

PICTURE NOT FOUND

SON OF THE SEA GOD (NOT REALLY)

• Triton was discovered in 1846

• Its nearly spherical and has a nearly circular, retrograde orbit

• It is 1700 mi in diameter

• Speculation: Triton was captured 3 or 4 billion years ago by Neptune’s gravity

• Triton is the only moon of notable size

• Most likely had an elliptical orbit, but then the tides caused the orbit to become circular

SON OF THE SEA GOD (NOT REALLY)

• Density: 2100 kg/m^3

• Two parts rock and one part ice

• Rocky core, liquid mantle, and icy crust

• Thin nitrogen atmosphere

• Tidal force has caused most the surface features to smooth out

• The present surface is about 100 million years old

SON OF THE SEA GOD (NOT REALLY)

• Puzzling: there is a wrinkled terrain near the south polar region

• Speculation: lake-like features on Triton are calderas of extinct cyrovolcanos

• The “lava” of these volcanos would be a mixture of methane, ammonia, and water (very low melting point compared to water)

• Temperature: -395 F

• Voyager 2 captured 8 km plumes of nitrogen gas that had been warmed by radioactive decay

FROZEN LAKE FORMATION

SOMETHING TO LOOK FORWARD TO

• Triton makes tides on Neptune

• Neptune causes Triton to spiral inwards

• Within the next quarter billion years Triton will reach the Roche Limit

• Roche Limit: the distance at which a planet creates tides on its moon’s solid surface high enough to pull the moon apart

• The destruction of Triton will create a new ring system