Press release
467KB
july 14, 2015 - NASA
NASA - How Big Is Pluto? New Horizons Settles Decades-Long Debate
NASA’s New Horizons mission has answered one of the most basic questions about Pluto—its size.
Mission scientists have found Pluto to be 1,473 miles (2,370 kilometers) in diameter, somewhat larger than many prior estimates. Images acquired with the Long Range Reconnaissance Imager (LORRI) were used to make this determination. This result confirms what was already suspected: Pluto is larger than all other known solar system objects beyond the orbit of Neptune.
“The size of Pluto has been debated since its discovery in 1930. We are excited to finally lay this question to rest,” said mission scientist Bill McKinnon, Washington University, St. Louis.
Pluto’s newly estimated size means that its density is slightly lower than previously thought, and the fraction of ice in its interior is slightly higher. Also, the lowest layer of Pluto’s atmosphere, called the troposphere, is shallower than previously believed.
Measuring Pluto’s size has been a decades-long challenge due to complicating factors from its atmosphere. Its largest moon Charon lacks a substantial atmosphere, and its diameter was easier to determine using ground-based telescopes. New Horizons observations of Charon confirm previous estimates of 751 miles (1208 km) kilometers) across
LORRI has also zoomed in on two of Pluto’s smaller moons, Nix and Hydra.
“We knew from the time we designed our flyby that we would only be able to study the small moons in detail for just a few days before closest approach,” said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute, Boulder, Colorado. “Now, deep inside Pluto’s sphere of influence, that time has come.”
Nix and Hydra were discovered using the Hubble Space Telescope in 2005. Even to Hubble, they appeared as points of light, and that’s how they looked to New Horizons until the final week of its approach to Pluto. Now, the latest LORRI images show the two diminutive satellites not as pinpoints, but as moons seen well enough to measure their sizes. Nix is estimated to be about 20 miles (about 35 kilometers) across, while Hydra is roughly 30 miles (roughly 45 kilometers) across. These sizes lead mission scientists to conclude that their surfaces are quite bright, possibly due to the presence of ice.
What about Pluto’s two smallest moons, Kerberos and Styx? Smaller and fainter than Nix and Hydra, they are harder to measure. Mission scientists should be able to determine their sizes with observations New Horizons will make during the flyby and will transmit to Earth at a later date.
071215_pluto_alone
1600x851, 407KB
201507130003hq
3580x2832, 4MB
7-8-15_pluto_color_new_nasa-jhuapl-swri-tn
1041x1041, 174KB
mh-07-10-15_puto_image_annotated
1920x1080, 386KB
new_horizon_wf-1041
1041x910, 965KB
new_horizons_launch
3008x2000, 362KB
nh-7-10-15_pluto_image_nasa-jhuapl-swri
2000x1394, 322KB
nh-7-13-15_charon_image_nasa-jhuapl-swri
1600x744, 118KB
nh-7-13-15_pluto_image_nasa-jhuapl-swri
1600x1126, 508KB
nh-alice-bowman
1041x1533, 588KB
nh-color-pluto-charon
1422x744, 131KB
nh-pluto-bw-series-7-6-2015
2998x1600, 391KB
nh-pluto-7-11-15
1042x1042, 61KB
nh-pluto-charon-earth-size
1041x1041, 1MB
nh-pluto-color-7-6-2015
1041x723, 230KB
nh-pluto-moonlight
1920x1080, 239KB
nh-pluto_charon_150709
1041x425, 17KB
nh-sc-pluto-illustration
1041x833, 693KB
nh-styx-kerberos-loop-larger
1500x600, 1MB
nh-women-launch
1041x1388, 1MB
nh-women
1080x456, 446KB
pluto-annotated
1920x1080, 390KB
pluto_charon_color_final
1041x781, 31KB
Related news |
||
|
|
|
february 28, 2024
|
february 13, 2024
|
january 12, 2024
|
|
NASA and Intuitive Machines will co-host a televised news conference at 2 p.m. EST Wednesday, Feb. 28, from the agency’s Johnson S... |
NASA will provide live coverage of the launch and docking of a Roscosmos cargo spacecraft carrying about three tons of food, fuel,... |
NASA will host a media teleconference at 12 p.m. EST, Wednesday, Jan. 17, to discuss the upcoming launch and science objectives of... |
Download all 
You might be interested in |
||
|
|
|
january 08, 2024
|
september 25, 2023
|
august 18, 2023
|
|
NASA and the Mohammed Bin Rashid Space Centre (MBRSC) have entered into an agreement for MBRSC to provide the Crew and Science Air... |
NASA will host a media teleconference at 4 p.m. EDT on Tuesday, Sept. 26, to discuss the upcoming annular solar eclipse. The annul... |
Editor's Note: This release has been updated to add additional graphics, captions, and to spell out the words degrees Fahrenheit a... |
Italian 
Download all 
Share
Share via mail 
Automotive
Sport
Events
Art&Culture
Design
Fashion&Beauty
Food&Hospitality
Technology
Nautica
Racing
Excellence
Corporate
OffBeat
Green
Gift
Pop
Heritage
Entertainment
Health & Wellness