Jimmy Westlake Presentation notes from today's Rotary meeting
Pluto was discovered in 1930 at the Percival Lowell Observatory by Clyde Tombaugh. At that time they thought it was 3 times the size of Earth. By 1950 they thought the same size. The joke at the time was that Pluto was shrinking so quickly that by 1968 it would disappear. James Cristy discovered a moon orbiting Pluto. Charon gave a scale comparison and showed that 500 Pluto’s = 1 Earth. Other moons that have been discovered for Pluto since are Nix, Hydra, P4 and P5.
Pluto's orbit is eccentric and is actually closer to the sun than Neptune at times (the last being 1979 to 1999). No other planet crosses the orbit of another planet’s. Pluto is 4.5 billion miles away from Earth so we don’t know what it’s surface looks like.
Mike Brown killed Pluto. He discovered Eris/Dysonia, the “10th” planet so there was concern about there being too many planets (detrimental to 3rd graders memorization abilities…)
2005-2006 International Astronomy Union (IAU) came up with a definition for a planet with 3 criteria:
1. A Planet must orbit it’s star (sun) directly. Hence our moon not being a planet
2. Be a hydrostatic sphere or have enough mass to collect itself as a sphere.
3. Dominant enough in its neighborhood to be free of all other debris.
Pluto is in a Kyperbelt. Icy asteroids, etc. Thus, Pluto doesn’t meet the 3rd criterion so, by this definition Pluto was demoted to Dwarf Planet status along with 4 others that have been discovered in our Solar System called Ceres, Makemake, Haumea and Eris. Interestingly, not even the earth has cleared all debris. There are 1400 Asteroids in Earth’s orbit and one scheduled for a near miss in 2029.
In January 2006, a few months before Pluto was demoted as a Planet to Dwarf, the New Horizons SpaceCraft was launched as “First launch to the last planet.” It is currently en route faster than a bullet from a high speed rifle scheduled to reach Pluto 10 years after its launch. In 2006 we didn’t know about Pluto’s 4 other moons besides Charon be we now know that at that speed debris as small as a butterfly could crush the spacecraft so it has to travel between Charon and Pluto to pass by Pluto close enough to get pictures. There are many potential disasters to overcome between now and then to achieve this goal. The spaceship will arrive near Pluto in 2016 and will take photos and conduct tests - the photos will travel via radiomagnetic waves and take 4.5 hours to reach Earth. Similarly it is 4.5 light years away.
Other facts from the presentation: It has been theorized that Pluto could have crashed into Neptune ions ago and evidenced by Neptune having a moon Triton, that orbits Neptune counter to the way Neptune revolves “swims upstream”. The theory that Pluto is a result of a collision with Neptune has been disproven.
Also, the closest Solar System to us (Star with orbiting planets) is 26 light years away. There are approximately 1700 Solar Systems identified in The Milky Way Galaxy at this time and since 1995.
Leslie D. Gamel