STATES CHRONICLE – Pluto has been challenging scientists since its discovery in 1930 by Clyde Tombaugh, at the time a young astronomer at Arizona’s Lowell Observatory. Specialists had long believed there was a ninth planet in the solar system, but it took Tombaugh a year of tedious comparison of telescope photos to find it.
Now, a recent fly-by by NASA’s New Horizons exploratory spacecraft has dramatically expanded scientific knowledge of this dwarf planet, revealing it to be much colder than anyone believed.
New Horizons Data Reveals Surprisingly Frigid Temperature
Pluto isn’t very big, in astronomical terms. This remote, icy world is only about two-thirds as large as the Earth’s Moon. Both its small size and position as the outermost of the planets circling the Sun meant it must be much colder than the coldest natural temperature ever recorded on Earth. This latter was a frigid minus 135.8 degrees Fahrenheit, registered in Antarctica.
Earthbound instruments led scientists to expect temperature readings of about minus 280 degrees Fahrenheit on Pluto. Surprisingly, temperature readings sent back to Earth via the New Horizons data revealed a beyond-frigid temperature of minus 330 degrees Fahrenheit, 50 degrees colder than anticipated.
On Earth, smog tends to make cities hotter. In contrast, on this icy planet, the reverse seems to be true. Pluto’s small size and a correspondingly weak gravity are seemingly causing its atmosphere to continually leak into space.
However, Xi Zhang, a University of California at Santa Cruz planetary scientist, explained the far-distant sun’s ultraviolet rays create a smog-like haze. The sun breaks down methane, nitrogen, and other gases in the thin atmosphere into a haze of solid particles. Zhang speculates this abundant haze absorbs a lot of solar radiation, shielding the surface and resulting in colder-than-expected temperatures.
A super-chilly temperature wasn’t the only surprise. The New Horizons spacecraft sent back incredible photos of ice-mountains, enormous craters, and sweeping plains. While it’s unlikely to become anyone’s vacation destination, Pluto still remains a mysterious dwarf planet with more surprises waiting for future explorers.
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