Ancient Nitrogen, a Key Element for Life, Found on Mars
U.S. space researchers say they have found more evidence that the planet Mars could have once been able to support life.
NASA scientists said Tuesday the Curiosity Mars rover found nitrates in Martian rocks. Nitrates are compounds that contain nitrogen, an element essential for life.
But the scientists say there is no evidence the nitrogen came from living things and stress that the Martian surface cannot support any forms of life.
They believe the nitrates are ancient and probably came from meteorites or lightning strikes.
This is not the first sign that the planet may have at one time been habitable. Past discoveries show signs that fresh water once covered the Martian surface.
Yemeni President Flees Palace as Houthis Advance South
Yemeni officials said President Abd-Rabbu Mansour Hadi fled his palace in the southern city of Aden for an undisclosed location in the city Wednesday as Houthi fighters continued their advance to the south.
The officials denied earlier reports that Mr. Hadi had left the city entirely. Aden has been a refuge for Mr. Hadi since last month, when he escaped house arrest by the Houthis in the capital, Sana'a, and went to the city on the Gulf of Aden to try to establish his government there.
The Houthis captured Sana'a last September and have been advancing south toward Aden. The reports that Mr. Hadi had fled came after the rebels took control of the key Al-Anad airbase about 60 kilometers north of the city following clashes with pro-Hadi forces.
Al-Anad was an important intelligence site used by U.S. personnel in the drone campaign targeting militants from the Yemen-based al-Qaida in the Arabian Peninsula. The U.S. announced Saturday that all of its remaining personnel had left the country because of the deteriorating security situation.
Mr. Hadi appealed to the U.N. Security Council on Tuesday to authorize a military intervention to halt the Houthi advance.