Obama, Hawking congratulate NASA on Pluto Flyby

US President Barack Obama and physicist Stephen Hawking were among several politicians, scientists and astronauts who today congratulated NASA for its New Horizons mission's successful historic Pluto flyby.
"Pluto just had its first visitor! Thanks @NASA - it's a great day for discovery and American leadership," tweeted Obama.
Obama had earlier tweeted to congratulate NASA's New Horizons on completing a three-billion-mile journey, while using the much-trending hashtag #PlutoFlyby.
The New Horizons spacecraft phoned home 13 hours after the actual flyby yesterday to tell the New Horizons mission team and the world it had successfully accomplished the historic first-ever flyby of Pluto.

Former US secretary of state Hillary Clinton also tweeted about the successful mission.
"@NASANewHorizons traveled 3 billion miles in nine years to forge a new frontier. Let's always keep exploring," tweeted Clinton, a Democrat Presidential hopeful in 2016.

Renowned physicist Hawking also congratulated the New Horizons team at NASA for the historic Pluto flyby.
"I would like to congratulate the New Horizons team at NASA on their pioneering decade-long mission to explore the Pluto system in the Kuiper Belt," he said in a video message shared by NASA.
"Billions of miles from Earth, this little robotic spacecraft will show us the first glimpse of mysterious Pluto, the distant icy world on the edge of our solar system.

"It is 50 years since the first successful mission to Mars Mariner 4 sent 21 images of the red planet. Now the solar system will be further opened up to us, revealing the secrets of distant Pluto.
"The revelations of New Horizons may help us to understand better how our solar system was formed. We explore because we are human and we want to know. I hope that Pluto will help us on that journey. I will be watching closely and I hope you will too," he said.
NASA also received some out-of-the-world greetings from astronaut Scott Kelly who is at the International Space Station for a year-long stay.

"Day 109. Watched the sun set on a day that saw a #NewHorizon on #Pluto. Good night from @space_station! #YearInSpace," he tweeted.
Astronaut Buzz Aldrin also tweeted: "The #PlutoFlyby helps reflect inward about its influence to embark outward from Earth with human exploration settlements into the universe."
Google had yesterday celebrated the Pluto Flyby with an adorable doodle. The doodle showed a cartoonish New Horizons spacecraft zipping past the icy dwarf planet.