The
World is reading the fly-by and just minutes before the long-awaited flyby took
place at 7:49AM ET, NASA "teased" the final full-frame color image of
Pluto set to be released before the event by publishing it on Instagram. It was
taken at about 4PM ET on July 13th, according to NASA, from 476,000 miles away.
The full-resolution image will be released after the flyby countdown is
complete.
Nasa's New Horizons
spacecraft has made the first visit to Pluto, speeding past at 14km per second.
The probe was set to grab more pictures and other data as it passed 12,500km
from Pluto. Controllers got a last
health status report, before the robotic craft turned its antenna away from the
Earth to concentrate on its target. Only when New Horizons has its trove of
images safely in its onboard memory will it call home again. This is not
expected to happen until just after midnight (GMT) into Wednesday. It means there will be a long, anxious wait
for everyone connected with the mission, as they hold out for a signal that
will be coming from almost five billion km away.
New Horizons' flyby
of 2,370km-wide Pluto is a key moment in the history of space exploration. "It's really historic what the US has
done, and the New Horizons team is really proud to have been able to run that
anchor leg and make this accomplishment." Says Nasa science chief. It marks the fact that every body in that
system - from Mercury through to Pluto - will have been visited at least once
by a space probe.
Pluto, is the largest known object in the Kuiper
belt, the second-most massive known dwarf planet in the Solar System and the
tenth-most massive known body directly orbiting the Sun. Pluto is believed, to
be primarily made of rock and ice and is
relatively small—about one-sixth the mass of the Moon and one-third its volume.
Light from the Sun takes about 5.5 hours to reach Pluto at its average distance.
Pluto was discovered
in 1930 and was originally considered the ninth planet from the Sun. After
1992, its status as a planet fell into question following the discovery of the
Kuiper belt, a ring of objects beyond Neptune that includes Pluto among other
large bodies. In 2005, Eris, which is 27% more massive than Pluto, was
discovered, which led the International Astronomical Union (IAU) to define the
term "planet" formally for the first time the following year. This definition excluded Pluto and
reclassified it as a member of the new "dwarf planet" category (and
specifically as a plutoid). Pluto has
five known moons: Charon (the largest, with a diameter just over half that of
Pluto), Styx, Nix, Kerberos, and Hydra.
Today,
i.e., on 14 July 2015, the New Horizons
probe will fly by Pluto, the first spacecraft to do so. NASA plans for New Horizons to take detailed
measurements and images of Pluto and its moons. After this, there are plans for New Horizons
to visit another object in the Kuiper belt. When
New Horizons makes its historic
flyby of Pluto, it will be focusing in on just one face of the dwarf planet. In the image NASA released of Charon
yesterday, astronomers pointed out a collection of vaguely-defined features on
the surface of Pluto’s biggest moon. Now, with the latest capture, the New
Horizons team has confirmed that the big dent in the icy rock’s surface is in
fact an impact crater, surrounded by a couple of deep canyons—one larger than
Earth’s Grand Canyon.
At a press
conference, New Horizons’ top dog Alan Stern announced that his team has
calculated Pluto’s most accurate diameter yet: about 736 miles from one end to
the other, give or take 6 miles. Yet it
is impossible to measure Pluto’s size
without also knowing its distance from Earth.
New Horizons is literally aiming for the unknown. The reason nobody
knows Pluto’s exact location is because humans have only known about the planet
for 85 years, which is about a third of the time it takes for Pluto to orbit
the sun. The uncertainty is relatively small, but it affects all kinds of
things.
New Horizons images
have dramatically reduced uncertainty in Pluto's diameter. Stern reported
Pluto's radius to be 1185 +/- 10 kilometers, so its diameter is 2370 +/- 20 km.
A larger diameter than thought means a
lower density than thought, which means it has a higher proportion of ice to
rock than thought. At the moment these comparisons are all qualitative; we'll
see quantitative ones eventually. New
Horizons compositional measurements have confirmed that Pluto has a polar cap
made of methane and nitrogen ices.
Astro-scientists are
eagerly waiting for more closer images and that is very interesting.
With regards – S.
Sampathkumar
14th July 2015.
