Astronmers spy evidence of water plumes on Jupiter's moon Europa
Scientists have viewed through NASA's Hubble Space Telescope what is believed to be plumes of water shooting up from the surface of Jupiter's moon Europa, NASA said Monday.
The first sighting took place in 2012, and three more were made over a 15-month period from 2013 to 2014.
The potential plumes were only observed three out of 10 times when Europa passed by Jupiter, suggesting that the eruptions are intermittent, he said.
"Today, we are presenting new Hubble evidence for water vapor plumes being expelled from the icy surface of Europa," William Sparks, astronomer with the Space Telescope Science Institute in Baltimore told reporters on a conference call.
Using ultraviolet images taken by Hubble, a space telescope that was launched in 1990, the potential plumes are seen around the southern edge of Europa and appear as "dark fingers or patches of possible absorption," Sparks said.
Europa, one of more than 50 moons circling the gas giant, is considered by NASA as a "top candidate" for life elsewhere in the solar system because it is believed to possess a massive, salty, subsurface ocean that is twice the size of Earth's.
Scientists are thrilled by the discovery of these "high altitude water vapor plumes" as they could provide a chance to collect water samples from the moon via an orbiting satellite rather than landing a craft and drilling into the surface, which could be kilometers thick.
Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington said that “Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system. These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”
NASA announced last year that it intends to send a robotic spacecraft, equipped with a suite of scientific instruments, to circle Europa in the 2020s.
This mission will not seek to find life, but will measure the habitability of Europa, to see if conditions exist that could sustain living organisms on the moon which orbits Jupiter every three and a half days.
Last year, data from Hubble confirmed that Jupiter's largest moon, Ganymede, has an underground ocean that contains more water than Earth's, broadening the hunt for places in the solar system where life might be able to exist.
According to the press release published on the NASA website, evidence of the plumes was first sighted in 2012 by a team led by Lorenz Roth of the Southwest Research Institute in San Antonio.
This first sighting suggested that plumes of water vapor were being expelled some 160 kilometers (100 miles) into space from the moon's surface.
The NASA team estimates that the plumes have ability to reach as far as 200 kilometers (125 miles) into space before the gravitational pull of the moon drags the material back to the surface.
Both teams have used the Hubble telescope in their observations, but employed different methods of observing Europa and arriving at the conclusion that these plumes likely exist.
"I do want to stress that the observations are at the limit of what Hubble can do," Sparks told reporters. "We do not claim to have proven the existence of plumes but rather to have contributed evidence that such activity may be present."
Europa is the second moon in our solar system believed to have the plumes which are expelled from the surface. NASA's Cassini orbiter in 2005 found similar plumes of water vapor and dust shooting out from the surface of Saturn's moon Enceladus.
We may have to wait a few more years for confirmation of the existence of these plumes on Europa. Should the NASA team choose to investigate further they could use the NASA’s James Webb Space Telescope, launching in 2018, which will be equipped with infrared imaging capabilities.
Paul Hertz, director of the Astrophysics Division at NASA Headquarters in Washington said that “Hubble’s unique capabilities enabled it to capture these plumes, once again demonstrating Hubble’s ability to make observations it was never designed to make, This observation opens up a world of possibilities, and we look forward to future missions -- such as the James Webb Space Telescope -- to follow up on this exciting discovery.”
(Staff with AFP)
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