Five mysteries about Pluto that flyby mission can unravel

Indians cheered when the Mars Orbiter Mission (MOM) of the Indian Space Research Organisation (ISRO) successfully traversed through space for close to one year to get into an orbit around Mars in September 2014. A similar moment awaits the world on Tuesday night when NASA's New Horizons mission will flyby Pluto after an epic journey lasting nearly a decade. It will be a giant step for humanity as a man-made object would cross the farthest point in the solar system. This is indeed a moment of glory for Pluto, whose status was downgraded to that of a "dwarf planet" by planetary scientists in 2006.

Here are five things that the New Horizons mission could unveil about Pluto, also known as one of the largest known Trans-Neptunian Objects:

How does Pluto look like?

Pluto was discovered by Clyde Tombaugh, who was a self-taught astronomer, in 1930 using a technique called "blink comparator". After the advent of the space age several decades later, successive probes and planetary missions, including space telescope Hubble, have imaged Pluto but from great distances. New Horizons is the first probe to go so near to the dwarf plane. In images already beamed by this probe, Pluto first appeared as a fuzzy round object and then started revealing its distinct surface features. The probe has payload called Long Range Reconnaissance Imager (LORRI) which will help scientists know in greater detail how the distant planetary object looks like. New Horizons is constantly sending images as it approaches Pluto. The best images would come when the probe reaches its closest point - about 12,500 kilometers - during the flyby.

How big is Pluto?

Measuring the size of Pluto has been a long-standing challenge for space and planetary scientists. New Horizons mission will answer basic questions about size of the Pluto. Based on data received so far, scientists say that Pluto is 2370 kilometer in diameter - it is larger than previously estimated. It is also larger than other known solar system objects beyond the orbit of Neptune. NASA scientists feel that the estimated size of Pluto means that its density is slightly less than earlier projections and that the proportion of ice in its interior is slightly higher.

How is Pluto's geology?

After getting a series of images from LORRI, mission scientists feel they are close enough to start seeing Pluto's geology. The image taken on July 9 when the probe was 5.4 million kilometers away have revealed the first signs of discrete geologic features of Pluto. It shows the side of Pluto that always faces its largest moon, Charon, and includes the so-called "tail" of the dark whale-shaped feature along its equator. It also revealed structures tentatively identified as polygonal features, a complex band of terrain stretching east-northeast across the dwarf planet, about 1,000 miles long. Just imagine the clarity of these features when the probe is just a 12,500 kilometers away from Pluto.

What about Pluto's moons?

Pluto has its set of moons - four of them smaller and one big one called Charon. Two small moons - Nix and Hydra - were discovered using the Hubble Space Telescope in 2005. Based on LORRI data, scientists now have a clearer idea about these moons. Nix is estimated to be about 35 kilometers across, while Hydra is 45 kilometers across. Their surfaces are quite bright, possibly due to the presence of ice. The other two moons - Kerberos and Styx - are smaller and New Horizons probe is expected to yield data that will help measure their sizes. Pluto's largest moon, Charon has diameter of about 1200 kilometers, as estimated from ground-based telescopes.

And its atmosphere:

While LORRI will tell scientists about features and size of Pluto and its moons, other instruments onboard will sniff signatures about Pluto's atmosphere. These sensors have already picked up nitrogen escaping from Pluto. The early detection of nitrogen could mean that Pluto's atmosphere is different from what has been thought of so far. Ice caps on Pluto are probably made of nitrogen and methane ice. It will get clearer as the probe goes nearer the plant and flies pretty close to it during the flyby. Data will also be gathered to know if Pluto and its moon Charon share any common atmosphere.

So fasten your seatbelts and be ready for big announcements from NASA on Wednesday by when scientists hope to get images from New Horizons and share the results. The mission will continue beyond Pluto into the Kupier belt and will hopefully unravel more fascinating tales about our universe.