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15 years before its official discovery, it was photographed in 1915 by Lowell Observatory, which didn't know what it was |
Pluto
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$1,200 |
DJ |
PLANETARY SCIENCE |
2021-10-22 |
#8495 |
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Features on this body include Tombaugh Regio & Sleipnir Fossa, named for a horse that carried Odin to the underworld |
Pluto
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FJ |
THE SOLAR SYSTEM |
2018-10-16 |
#7842 |
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Discovered in 1930, this body has an estimated diameter of only 1,473 miles |
Pluto
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$200 |
J |
ASTRONOMY |
2018-02-20 |
#7702 |
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In March 1930 its discovery was announced at Lowell Observatory in Arizona |
Pluto
DD
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$4,000 |
DJ |
ASTRONOMY |
2012-10-17 |
#6458 |
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In 2005, 2 additional moons, Hydra & Nix, were discovered orbiting this dwarf planet |
Pluto
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$400 |
J |
ASTRONOMY |
2012-03-02 |
#6325 |
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The International Astronomical Union said in 2006 that this object was really part of the Kuiper Belt, not a true planet |
Pluto
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$200 |
J |
ASTRONOMY & ASTROLOGY |
2010-05-04 |
#5912 |
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In the time it takes this planet to orbit the sun once, you'd get over 90,000 deliveries of your daily paper |
Pluto
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$400 |
J |
THE PLANETS |
2004-12-03 |
#4660 |
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It's the only planet that has yet to be visited by a spacecraft |
Pluto
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$600 |
J |
THE PLANETS |
2004-11-23 |
#4652 |
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(Sarah of the Clue Crew stands outside the dome of the Adler Planetarium in Chicago.) The first modern planetarium in the Western Hemisphere, the Adler, opened in 1930, about the time of this planet's discovery |
Pluto
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$1,200 |
DJ |
THE ADLER PLANETARIUM |
2004-10-11 |
#4621 |
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The one named by an 11-year-old |
Pluto
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$800 |
J |
PLANETARY DISTINCTIONS |
2004-10-05 |
#4617 |
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Some scientists want to reclassify this planet as a wayward moon |
Pluto
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$600 |
J |
DID WE PLANET THAT WAY? |
2004-07-02 |
#4580 |
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Moving at 2.9 miles per second, this planet has the slowest orbital speed of any planet in our solar system |
Pluto
DD
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$1,000 |
DJ |
THE SOLAR SYSTEM |
2004-05-28 |
#4555 |
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In 1905 Percival Lowell began a search for this planet, which was discovered in 1930, 14 years after his death |
Pluto
DD
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$2,000 |
DJ |
ASTRONOMY |
2004-05-03 |
#4536 |
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In 1978 astronomer James Christy named its moon in honor of his wife Charlene |
Pluto
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FJ |
THE PLANETS |
2003-12-10 |
#4433 |
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It's actually too small to influence other planets' orbits, the theory that led to its discovery |
Pluto
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$400 |
J |
THE PLANETS |
2003-04-14 |
#4296 |
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This root precedes -crat to mean one who rules by virtue of wealth |
Pluto
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$2,000 |
DJ |
PLANET NAMES |
2002-04-12 |
#4065 |
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KX76, a Kuiper belt object discovered in 2001, is about half the size of this smallest planet |
Pluto
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$800 |
J |
THE OTHER PLANETS |
2002-02-05 |
#4017 |
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This planet was named in 1930 by an 11-year-old British girl, Venetia Burney, who won a "Name Planet X" contest |
Pluto
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$600 |
J |
THE PLANETS |
2002-01-14 |
#4001 |
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This planet has more in common with Triton, Neptune's largest moon, than it does with any of the other planets |
Pluto
DD
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$800 |
DJ |
THE SOLAR SYSTEM |
2000-10-03 |
#3697 |
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A 25-year-long telescope search for it ended with its discovery in 1930 |
Pluto
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$300 |
J |
THE PLANETS |
2000-04-04 |
#3597 |
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On Nov. 13, 1999 a body circling HD 209458 became the first new planet to be photographed since this one |
Pluto
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FJ |
SPACE |
2000-03-16 |
#3584 |
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On February 11, 1999 it again became the farthest planet from the sun & will remain so for 248 years |
Pluto
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$200 |
DJ |
ASTRONOMY |
1999-04-23 |
#3380 |
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It's the only planet you can't see using ordinary binoculars; you need a telescope |
Pluto
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$400 |
DJ |
THE SOLAR SYSTEM |
1999-02-17 |
#3333 |
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Astronomer Clyde Tombaugh discovered this tiny planet in 1930 |
Pluto
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$500 |
J |
THE PLANETS |
1997-04-10 |
#2914 |
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This smallest planet always keeps the same face toward Charon, its moon |
Pluto
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$400 |
J |
THE PLANETS |
1996-12-09 |
#2826 |
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It's the only planet in our solar system discovered by an American, Clyde Tombaugh |
Pluto
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$500 |
J |
THE PLANETS |
1996-10-01 |
#2777 |
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The orbit of this smallest planet has the greatest eccentricity |
Pluto
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$600 |
DJ |
ASTRONOMY |
1996-05-16 |
#2709 |
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It was the last of the 9 planets discovered |
Pluto
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$300 |
J |
THE PLANETS |
1996-02-21 |
#2648 |
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It would take about 25 of this smallest planet to make up the mass of the second smallest, Mercury |
Pluto
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$300 |
J |
THE PLANETS |
1995-06-26 |
#2506 |
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Charon does not orbit this planet; they both orbit a point between them |
Pluto
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$800 |
DJ |
THE PLANETS |
1995-06-22 |
#2504 |
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This planet will be closer to the Sun than Neptune until March 15, 1999 |
Pluto
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$800 |
DJ |
ASTRONOMY |
1995-05-09 |
#2472 |
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It takes Charon 6.4 days to orbit this planet |
Pluto
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$1,000 |
DJ |
THE PLANETS |
1994-09-29 |
#2314 |
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In 1930 Clyde W. Tombaugh discerned this new planet among millions of star images in photographs |
Pluto
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$400 |
DJ |
ASTRONOMY |
1993-09-28 |
#2082 |
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This planet has made only about 1/4 of an orbit since it was discovered in 1930 |
Pluto
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$500 |
J |
ASTRONOMY |
1993-06-14 |
#2036 |
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It was located by 20th century scientists looking for Planet X |
Pluto
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$100 |
J |
THE PLANETS |
1993-06-07 |
#2031 |
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The diameter of this planet is estimated to be less than 2,000 miles |
Pluto
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$500 |
J |
ASTRONOMY |
1993-05-12 |
#2013 |
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Its orbit takes about 248 Earth years, the longest of any planet in the solar system |
Pluto
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$400 |
DJ |
THE PLANETS |
1993-01-19 |
#1932 |
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Even the Hubble Space Telescope can't reveal the surface features of this outer, smallest planet |
Pluto
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$400 |
DJ |
THE PLANETS |
1992-09-10 |
#1839 |
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It's the only planet in the solar system smaller than the Earth's moon |
Pluto
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$800 |
DJ |
THE PLANETS |
1992-05-05 |
#1782 |
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This planet's only known moon, Charon, was discovered by James W. Christy in 1978 |
Pluto
DD
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$1,000 |
DJ |
THE PLANETS |
1991-12-11 |
#1678 |
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This planet is smaller than our moon |
Pluto
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$600 |
DJ |
THE SOLAR SYSTEM |
1991-10-02 |
#1628 |
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This 9th planet's one moon has an orbit period of 6.4 days |
Pluto
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$100 |
J |
ASTRONOMY |
1991-06-19 |
#1583 |
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Because it is smallest & lightest, some astronomers think it should be considered an asteroid |
Pluto
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$800 |
DJ |
THE PLANETS |
1991-02-05 |
#1487 |
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Some believe that this small planet was originally a satellite of Neptune |
Pluto
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$200 |
DJ |
THE PLANETS |
1990-12-31 |
#1461 |
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In 1930, Clyde Tombaugh discovered this planet from photographic plates taken two moths earlier |
Pluto
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$200 |
DJ |
ASTRONOMY |
1990-09-18 |
#1387 |
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This icy planet takes 248 years to complete an orbit of the sun |
Pluto
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$400 |
J |
THE PLANETS |
1990-03-19 |
#1286 |
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It's the planet astronomers know least about |
Pluto
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$300 |
J |
THE PLANETS |
1989-01-16 |
#1011 |
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In 1950 the 1st measurements of this planet were made with the 200 inch telescope on Mt. Palomar |
Pluto
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$600 |
DJ |
THE SOLAR SYSTEM |
1988-09-23 |
#930 |
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This small outer planet may be a low-density ice ball |
Pluto
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$300 |
J |
ASTRONOMY |
1988-04-08 |
#840 |
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Evangeline Adams' 1931 "Astrology for Everyone" has no mention of Earth's or this planet's effects |
Pluto
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$1,000 |
DJ |
ASTROLOGY |
1988-02-23 |
#807 |
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Recent studies show this planet has a moon that's more than half its size |
Pluto
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FJ |
THE SOLAR SYSTEM |
1987-09-16 |
#693 |
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It has the most eccentric orbit of the 9 major planets |
Pluto
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$1,000 |
DJ |
ASTRONOMY |
1986-10-24 |
#490 |
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As this planet's furthest point, it's over 4.5 billion miles from the Sun |
Pluto
|
$800 |
DJ |
THE SOLAR SYSTEM |
1986-04-04 |
#410 |
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Its only known moon is appropriately named after the boatman Charon |
Pluto
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|
FJ |
THE PLANETS |
1986-03-31 |
#406 |
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Only for a 20-year period every 248 years is this planet closer to the Sun than Neptune |
Pluto
|
$400 |
J |
THE PLANETS |
1985-12-05 |
#324 |
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Last planet discovered & last chance for gas in the solar system |
Pluto
|
$200 |
J |
SPACE |
1984-09-17 |
#6 |