Russia, the US and the EU say that all sides have agreed to steps to "de-escalate" the crisis in Ukraine at talks in Geneva.
Nasa have announced official confirmation of the first Earth-like planet orbiting in the habitable zone of another star.
There is still no official explanation for the sinking, although the government has launched a formal inquiry.
President Obama has said that there is the possibility that diplomacy may de-escalate the situation in Ukraine.
Mr Obama also stressed that the Ukrainian people should make their own decisions about their own lives.
The US President was speaking to reporters at a White House press conference.
A 30-year-old runner from Stafford has won a half-marathon held in North Korea's capital Pyongyang, after it was opened to foreigners for the first time.
Will Marks, who lives in Shanghai, completed the race in 1 hour 23 minutes, and was among about 150 foreign runners to compete in front of 70,000 onlookers.
Mr Marks stayed in North Korea for three nights before the race on Sunday, but was not allowed to move around the city unaccompanied.
Officials checked participants' running gear several days before the race, and also made sure that hairstyles matched new guidelines that require all men to have short back and sides like President Kim Jong-Un.
Labour’s shadow foreign secretary, Douglas Alexander, has said the deal agreed over Ukraine at the Geneva talks would be "a welcome step forward" if implemented.
"Both Russia and Ukraine have a responsibility to deliver on their commitments to help resolve the ongoing tensions and ensure that stability is restored," Mr Alexander said.
"The days ahead will be a crucial test of Russia's stated resolve to help stabilise the situation, but this initial step is potentially a sign of progress."
Rescuers are still trying to find hundreds of missing passengers who were onboard a capsized South Korean ferry.
China Correspondent Lucy Watson reports:
An Earth-like planet confirmed by Nasa in the habitable zone around the Kelper-186 star has 'potential' to host liquid water - one of the pre-requisites for life as we know it to exist.
Nasa research scientist Tom Barclay has said that the hopes of the Kelper team have been answered with the discovery of Kepler-186f.
The discovery of the Earth-like planet orbiting star Kepler has demonstrated the existence of planets that could potentially hold life.
Scientists scouring the sky have discovered an 'Earth-like' planet in the habitable zone.
The new planet, dubbed Kepler-186f, was discovered using NASA's Kepler telescope, which was launched in March 2009 to search for Earth-sized planets in our corner of the Milky Way Galaxy.
A habitable zone planet orbits its star at a distance where any water on the planet's surface is likely to stay liquid. Since liquid water is critical to life on Earth, many astronomers believe the search for extraterrestrial life should focus on planets where liquid water occurs.
"Some people call these habitable planets, which of course we have no idea if they are," astronomer Stephen Kane said. "We simply know that they are in the habitable zone, and that is the best place to start looking for habitable planets."
It is one of those very rare days where the diplomats have defied the dismal expectations - including incidently their own- to deliver some significant progess
Remember just 24 hours ago the idea that these four people in the same room for seven hours would it'self have been deemed a success, so they have come much further and faster than anybody expected.
It is crucial to remember that it is an outline of a deal that is by no means a finished article. The headline will be of course the calls for the armed groups to disband and go home.
But there is trouble already tonight in Donetsk as the pro-Russians are saying we're not going anywhere until the Kiev camps have been dismantled.
Then the questions of how much power is being handed over to the east and what kind of say Moscow has in Ukraine's future need to be answered.
We have the beginnings of a deal, but plenty of scope for it to unravel.