Jane Greaves & George Bendo
Pluto tracking across the night sky, May 8-20, 1997. The superimposed red points show the moving point that the JCMT measured for the dwarf planet and its moons during this time.
Andrew Cooper/W. M. Keck Observatory
March 13, 2013, marks 20 years since the W. M. Keck Observatory began taking observations of the cosmos. Located in arguably one of the most extreme and beautiful places on the planet -- atop Mauna Kea, Hawai'i, 13,803 ft (4,207 m) above sea level -- the twin Keck domes have observed everything from asteroids, planets, exoplanets to dying stars, distant galaxies and nebulae. Seen in this photograph, the Keck I and Keck II telescopes dazzle the skies with their adaptive optics lasers -- a system that helps cancel out the turbulence of the Earth's atmosphere, bringing science some of the clearest views attainable by a ground-based observatory.
To celebrate the last two decades of incredible science, Discovery News has assembled some of the most impressive imagery to come from Keck.
William Merline, SWRI / W.M. Keck Observatory
Starting very close to home, the Keck II captured this infrared image of asteroid 2005 YU55 as it flew past Earth on Nov. 8, 2011.
Larry Sromovsky (University of Wisconsin)
Deeper into the solar system, the Keck NIRC2 near-infrared camera captured this beautiful observation of the oddball Uranus on July 11-12, 2004. The planet's north pole is at 4 o'clock.
W.M Keck Observatory/NASA/JPL-G.Orton
This is a mosaic false-color image of thermal heat emission from Saturn and its rings on Feb. 4, 2004, captured by the Keck I telescope at 17.65 micron wavelengths.
Antonin Bouchez (W. M. Keck Observatory)
A nice image of Saturn with Keck I telescope with the near infrared camera (NIRC) on Nov. 6, 1998. This is a composite of images taken in Z and J bands (1.05 and 1.3 microns), with the color scaling adjusted so it looks like Saturn is supposed to look to the naked eye.
Antonin Bouchez, W.M. Keck Observatory
This is Saturn's giant moon Titan -- a composite of three infrared bands captured by the Near Infrared Camera-2 on the 10-meter Keck II telescope. It was taken by astronomer Antonin Bouchez on June 7, 2011.
W. M. Keck Observatory/SRI/New Mexico State University
Another multicolored look at Titan -- a near-infrared color composite image taken with the Keck II adaptive optics system. Titan's surface appears red, while haze layers at progressively higher altitudes in the atmosphere appear green and blue.
Mike Brown, Caltech / W.M. Keck Observatory
This image of Neptune and its largest Tritan was captured by Caltech astronomer Mike Brown in September 2011. It shows the wind-whipped clouds, thought to exceed 1,200 miles per hour along the equator.
A color composite image of Jupiter in the near infrared and its moon Io. The callout at right shows a closeup of the two red spots through a filter which looks deep in the cloud layer to see thermal radiation.
Christian Marois, NRC and Bruce Macintosh, LLNL/W. M. Keck Observatory
HR 8799: Three exoplanets orbiting a young star 140 light years away are captured using Keck Observatory's near-infrared adaptive optics. This was the first direct observation by a ground-based observatory of worlds orbiting another star (2008).
Bob Goodrich, Mike Bolte, and the ESI team
Now to the extremes -- an image of Stephan's Quintet, a small compact group of galaxies.
W.M. Keck Observatory
The Egg Nebula: This Protoplanetary nebula is reflecting light from a dying star that is shedding its outer layers in the final stages of its life.
W. M. Keck Observatory
This is WR 104, a dying star. Known as a Wolf Rayet star, this massive stellar object will end its life in the most dramatic way -- possibly as a gamma-ray burst. The spiral is caused by gases blasting from the star as it orbits with another massive star.
W. M. Keck Observatory/UCLA
Narrow-field image of the center of the Milky Way. The arrow marks the location of radio source Sge A*, a supermassive black hole at the center of our galaxy.
Dr. Mark Morris (UCLA) Keck II, Mirlen instrument
A high resolution mid-infrared picture taken of the center of our Milky Way reveals details about dust swirling into the black hole that dominates the region.
Mansi Kasliwal, Caltech and Iair Arcavi, Weizmann Institute of Science/W. M. Keck Observatory
A false-color image of a spiral galaxy in the constellation Camelopardalis.
A scintillating square-shaped nebula nestled in the vast sea of stars. Combining infrared data from the Hale Telescope at Palomar Observatory and the Keck II telescope, researchers characterized the remarkably symmetrical “Red Square” nebula.
ESA, NASA, J.-P. Kneib (Caltech/Observatoire Midi-Pyrenees) and R. Ellis (Caltech)/W. M. Keck Observatory
Galaxy cluster Abell 2218 is acting as a powerful lens, magnifying all galaxies lying behind the cluster's core. The lensed galaxies are all stretched along the shear direction, and some of them are multiply imaged.
UC Berkeley/NASA/W. M. Keck Observatory
The central starburst region of the dwarf galaxy IC 10. In this composite color image, near infrared images obtained with the Keck II telescope have been combined with visible-light images taken with NASA’s Hubble Space Telescope.
Scientists are attempting to map Pluto's icy depths using old telescope data before a NASA spacecraft reaches the distant dwarf planet in 2015.
The researchers say they found hints of frozen chemicals hidden beneath Pluto's crust in data obtained by the James Clerk Maxwell Telescope (JCMT) on Hawaii in the late 1990s.
"This was a bit like using a telescope as a digger to mine into Pluto, but with less effort!" astrophysics researcher Jane Greaves of the University of St Andrews in Scotland said in a statement. [Photos of Pluto and Its Moons]
Pluto, which was only discovered in 1930, orbits between 2.7 billion and 4.5 billion miles (4.4 billion and 7.3 billion kilometers) from the sun. For comparison, Earth orbits 93 million, or 150 km, from our star. Powerful observatories, such as the Hubble Space Telescope, have taken detailed images and maps of Pluto in recent years, even discovering new moons around the dwarf planet. Nonetheless, Pluto has remained quite mysterious because it is so far away.
Earthlings will finally get a detailed look at part of the frigid body next year when NASA's New Horizons spacecraft flies by Pluto. The probe left Earth in 2006, the same year Pluto was dethroned from its position as our solar system's ninth planet. New Horizons will be just the fifth spacecraft to travel so far away from home, behind Pioneer 10, Pioneer 11, Voyager 1 and Voyager 2.
In anticipation of this historic mission, Greaves and her undergraduate student Ailsa Whitelaw said they looked at old data from JCMT's SCUBA (Submillimeter Common-User Bolometer Array), two instruments which scanned the cosmos in the submillimeter range of the electromagnetic spectrum — wavelengths between far-infrared and microwave.
The researchers found evidence of invisible 0.85 mm waves emitted from beneath the surface of Pluto, which they believe could be linked to a possible dry layer of frozen nitrogen and methane hidden under a dark surface patch of water ice and frozen polymers.
"I'm really excited to see what New Horizons will find a year from now," Greaves said in a statement. "Some researchers think that even deeper down, Pluto has liquid water, kept fluid by remnant heat from a big crash that formed its moons — if so the surface will probably look wrinkled. But the flyby is so quick that we'll need to follow up — maybe with future radar we can dig down even further."
Greaves will present her findings at the National Astronomy Meeting in Portsmouth, England this week.
More from SPACE.com:
Destination Pluto: NASA's New Horizons Mission in Pictures
Images: Dwarf Planet Eris, Pluto's Cosmic Twin
Our Solar System: A Photo Tour of the Planets