Water discovered for first time in atmosphere of habitable exoplanet

Until the late 20th century, astronomers had only identified the planets in our own solar system. But everything changed in 1995, when the discovery of the first exoplanet orbiting a Sun-like star was confirmed. Videographic on exoplanets. (AFP)
Updated 12 September 2019

Water discovered for first time in atmosphere of habitable exoplanet

  • Water is crucial in the search for life, in part because it carries oxygen

PARIS: Water has been discovered for the first time in the atmosphere of an exoplanet with Earth-like temperatures that could support life as we know it, scientists revealed Wednesday.
Eight times the mass of Earth and twice as big, K2-18b orbits in its star’s “habitable zone” at a distance — neither too far nor too close — where water can exist in liquid form, they reported in the journal Nature Astronomy.
“This planet is the best candidate we have outside our solar system” in the search for signs of life, co-author Giovanna Tinetti, an astronomer at University College London, told AFP.
“We cannot assume that it has oceans on the surface but it is a real possibility.”
Of the more than 4,000 exoplanets detected to date, this is the first known to combine a rocky surface and an atmosphere with water.
Most exoplanets with atmospheres are giant balls of gas, and the handful of rocky planets for which data is available seem to have no atmosphere at all.
Even if they did, most Earth-like planets are too far from their stars to have liquid water or so close that any H2O has evaporated.
Discovered in 2015, K2-18b is one of hundreds of so-called “super-Earths” — planets with less than ten times the mass of ours — spotted by NASA’s Kepler spacecraft.
Future space missions are expected to detect hundreds more in the coming decades.

“Finding water in a potentially habitable world other than Earth is incredibly exciting,” said lead-author Angelos Tsiaras, also from UCL.
“K2-18b is not ‘Earth 2.0’,” he said. “However, it brings us closer to answering the fundamental question: is the Earth unique?“
Working with spectroscopic data captured in 2016 and 2017 by the Hubble Space Telescope, Tsiaras and his team used open-source algorithms to analyze the starlight filtered through K2-18b’s atmosphere.
They found the unmistakable signature of water vapor. Exactly how much remains uncertain, but computer modelling suggested concentrations between 0.1 and 50 percent.
By comparison, the percentage of water vapor in Earth’s atmosphere varies between 0.2 percent above the poles, and up to four percent in the tropics.
There was also evidence of hydrogen and helium as well. Nitrogen and methane may also be present but with current technology remain undetectable, the study said.
Further research will be able to determine the extent of cloud coverage and the percentage of water in the atmosphere.

Water is crucial in the search for life, in part because it carries oxygen.
“Life as we know is based on water,” said Tinetti.
K2-18b orbits a red dwarf star about 110 light years distant — a million billion kilometers — in the Leo constellation of the Milky Way, and is probably bombarded by more destructive radiation than Earth.
“It is likely that this is the first of many discoveries of potentially habitable planets,” said UCL astronomer Ingo Waldmann, also a co-author.
“This is not only because super-Earths like K2-18b are the most common planets in our galaxy, but also because red dwarfs — stars smaller than our Sun — are the most common stars.”
The new generation of space-based star gazing instruments led by the James Webb Space Telescope and the European Space Agency’s ARIEL mission will be able to describe exoplanet atmospheres in far greater detail.
ARIEL, slated for a 2028 launch, will canvas some 1,000 planets, a large enough sampling to look for patterns and identify outliers.
“Over 4,000 exoplanets have been detected but we don’t know much about their composition and nature,” said Tinetti. “By observing a large sample of planets, we hope to reveal secrets about their chemistry, formation and evolution.”
 


Microsoft ends free Windows 7 security updates on Tuesday

In this Jan. 11, 2010 file photo, a display for Microsoft's Windows 7 is shown at the National Retail Federation's convention in New York. (AP)
Updated 14 January 2020

Microsoft ends free Windows 7 security updates on Tuesday

  • Microsoft is ending support Tuesday for Windows Server 2008 or 2008 R2 operating systems

NEW YORK: If you’re still using Microsoft’s Windows 7, your computer might soon be at risk.
Microsoft will stop providing free security updates for the system on Tuesday, meaning computers using it will be more vulnerable to malware and hacking.
Users who want to protect their computers need to upgrade to Windows 10. They may also need to buy new computers because older machines might not be compatible with Windows 10.
Tech companies typically phase out older systems after a number of years and focus efforts on updating current versions of software. Windows 7 came out in 2009. Windows 8, which came out in 2012, will have free support end in 2023.
Windows 10 starts at $139 for a basic, “Home” version. Microsoft charges $200 for a “Pro” version meant for businesses and individuals who need its advance features. Windows 10 comes with regular free updates for security and additional features. Although Windows 10 isn’t likely to be phased out anytime soon, older versions will require those updates to keep working.
Microsoft is also ending support Tuesday for Windows Server 2008 or 2008 R2 operating systems.
Those who run Windows 7 Professional or Windows 7 Enterprise can buy extended protection for up to three years. But it might be worthwhile to just to buy new PCs or get Windows 10.
Microsoft will also be ending support on Oct. 13 for Office 2010 a package that includes word processing and spreadsheet software. Owners need to explore newer versions of Office, including a subscription offering called Office 365.