Ethiopia says it has started the next phase of filling a controversial mega-dam on the Nile River, Egyptian authorities said Monday, raising tensions ahead of an upcoming UN Security Council on the issue.
The research is based on data gathered by NASA’s Lunar Reconnaissance Orbiter, in orbit around the moon since June 2009, as well as the agency’s Stratospheric Observatory for Infrared Astronomy airborne telescope, called SOFIA. The latter is a Boeing 747SP aircraft modified to carry a 2.7-meter telescope.
„Current theories suggest that Venus and the Earth may have started out alike. There might have been a lot of water on Venus and there might have been a lot of carbon dioxide on Earth,“ Professor Ingersoll explained.
But all that was to change. On Earth, life in the oceans took in carbon dioxide and turned it into limestone. On Venus, 30% closer to the Sun, any oceans boiled away and the water vapour added to the runaway greenhouse effect.
WHILE the surface conditions of Venus make the hypothesis of life there implausible, the clouds of Venus are a different story altogether. As was pointed out some years ago, water, carbon dioxide and sunlight—the prerequisites for photosynthesis—are plentiful in the vicinity of the clouds. Since then, good additional evidence has been provided that the clouds are composed of ice crystals at their tops and it seems likely that there are water droplets toward their bottoms. Independent evidence for water vapour also exists5.
Infrared spectra of Venus produced by a Fourier spectrometer flown aboard the NASA CV 990 jet aircraft were analyzed for water-vapor content by comparison with calculated model spectra. The reflecting layer model gave an abundance of 1.6 ± 0.4 μ of precipitable water for the two-way transmission of the Venus atmosphere. The scattering model resulted in a value of 0.25 ± 0.10 μ of water per scattering mean free path.
Using infrared imaging, one team discovered the presence of the compound hydrohalite—a material common in sea ice but which until now had never been observed off of Earth.
Water vapor appears on Mars today as thin, wispy clouds.
The Ion and Neutral Mass Spectrometer saw a much higher density of volatile gases, water vapor, carbon dioxide and carbon monoxide, as well as organic materials, some 20 times denser than expected. This dramatic increase in density was evident as the spacecraft flew over the area of the plumes.
Previous analyses inferred three different spectral types of Enceladean ice grains (Postberg et al. 2008, 2009a): Type 1 represents grains of almost pure water ice, Type 2 shows features consistent with grains containing significant amounts of organic material, and Type 3 is indicative of salt-rich water ice grains.
Before NASA’s Cassini mission studied Saturn and its moons for 13 years, beginning in 2004, Enceladus held many secrets. Cassini revealed that there was a global ocean between the moon’s icy crust and its rocky core.
Although the Cassini mission ended in a blaze of glory when it disintegrated in Saturn’s atmosphere, surprises from the data it collected will be released for years to come.
Mars today is a chilly desert. But ancient landscapes reveal a times when water may have flowed freely. Scroll to see how the red planet has evolved
Current theories of the formation and evolution of the terrestrial planets do support an Earth scale magnetic dipole (magnetic field) on Venus for perhaps the first billion years or so after formation.
The long-term evolutionary history of Venus’ climate largely remains a mystery.
(24. September 2009) The man who led the mission, Dr Mylswamy Annadurai, told the Times today how pleased he was at the discovery, which significantly enhances India’s position in its space race with China.
„It’s very satisfying,“ he said. „This was one of the main objectives of Chandrayaan-1, to find evidence of water on the moon.“
The reports from the Indian mission were backed up by the findings of two other studies to be published in the journal Science on Friday, showing that the water may be actively moving around, forming and reforming as particles mixed up in the dust on the surface of the moon.
(21.8.2018) As that statement indicates, scientists already knew that the lunar underground isn’t bone-dry. For example, in 2009, an impactor released by NASA’s Lunar Crater Observation and Sensing Satellite (LCROSS) blasted a bunch of water into space after slamming into a permanently shadowed region of Cabeus Crater, which lies near the moon’s south pole.
But it wasn’t clear from the LCROSS data where, exactly, that excavated ice originally lay — how much gray dirt once sat atop it. And, while several instruments have spotted tantalizing hints of exposed lunar ice over the years, these detections had remained unconfirmed until now.