NASA will discuss new results about ocean worlds in our solar system from the agency’s Cassini spacecraft and the Hubble Space Telescope during a news briefing 11 a.m. PDT (2 p.m. EDT) on Thursday, April 13. The event, to be held at NASA Headquarters in Washington, will include remote participation from experts across the country.
The briefing will be broadcast live on NASA Television and the agency’s website.
These new discoveries will help inform future ocean world exploration — including NASA’s upcoming Europa Clipper mission planned for launch in the 2020s — and the broader search for life beyond Earth.
Written by George McGinn Cosmology and Space Research September 27, 2016 at 4:32pm EST
In one of the most promising places in the Solar System where life may exist, astronomers using NASA’s Hubble Space Telescope have photographed what appears to be water vapor plumes escaping Jupiter’s moon Europa.
The team from the Space Telescope Science Institute (STScI) in Baltimore saw finger-like projections when viewing Europa as it past in front of Jupiter, according to team leader William Sparks.
The discovery occurred by accident as the team’s original proposal was to observe Europa to determine if it had an atmosphere or exosphere.
An exosphere of neon was detected on Earth’s Moon on August 17, 2015 based on study the data from the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft.
Water is a hot topic in the study of exoplanets, including “hot Jupiters,” whose masses are similar to that of Jupiter, but which are much closer to their parent star than Jupiter is to the sun. They can reach a scorching 2,000 degrees Fahrenheit (1,100 degrees Celsius), meaning any water they host would take the form of water vapor.
Astronomers have found many hot Jupiters with water in their atmospheres, but others appear to have none. Scientists at NASA’s Jet Propulsion Laboratory, Pasadena, California, wanted to find out what the atmospheres of these giant worlds have in common.
Researchers focused on a collection of hot Jupiters studied by NASA’s Hubble Space Telescope. They found that the atmospheres of about half of the planets were blocked by clouds or haze.
“The motivation of our study was to see what these planets would be like if they were grouped together, and to see whether they share any atmospheric properties,” said Aishwarya Iyer, a JPL intern and master’s degree candidate at California State University, Northridge, who led the study.
The new study, published in the June 1 issue of the Astrophysical Journal, suggests that clouds or haze layers could be preventing a substantial amount of atmospheric water from being detected by space telescopes. The clouds themselves are likely not made of water, as the planets in this sample are too hot for water-based clouds.
“Clouds or haze seem to be on almost every planet we studied,” Iyer said. “You have to be careful to take clouds or haze into account, or else you could underestimate the amount of water in an exoplanet’s atmosphere by a factor of two.”
In the study, scientists looked at a set of 19 hot Jupiters previously observed by Hubble. The telescope’s Wide Field Camera 3 had detected water vapor in the atmospheres of 10 of these planets, and no water on the other nine. But that information was spread across more than a dozen studies. The methods of analyzing and interpretation varied because the studies were conducted separately. There had not been one overarching analysis of all these planets.
To compare the planets and look for patterns, the JPL team had to standardize the data: Researchers combined the datasets for all 19 hot Jupiters to create an average overall light spectrum for the group of planets. They then compared these data to models of clear, cloud-free atmospheres and those with various cloud thicknesses.
The scientists determined that, for almost every planet they studied, haze or clouds were blocking half of the atmosphere, on average.
“In some of these planets, you can see water peeking its head up above the clouds or haze, and there could still be more water below,” Iyer said.
Scientists do not yet know the nature of these clouds or hazes, including what they are they made of.
“Clouds or haze being on almost all these planets is pretty surprising,” said Robert Zellem, a postdoctoral fellow at JPL and co-author of the study.
The implications of this result agree with findings published in the Dec. 14, 2015, issue of the journal Nature. The Nature study used data from NASA’s Hubble and Spitzer Space Telescopes to suggest that clouds or haze could be hiding undetected water in hot Jupiters. This new study uses exoplanet data from a single instrument on Hubble to uniformly characterize a larger group of hot Jupiters, and is the first to quantify how much of the atmosphere would be shielded as a result of clouds or haze.
The new research could have implications for follow-up studies with future space observatories, such as NASA’s James Webb Space Telescope. Exoplanets with thick cloud covers blocking the detection of water and other substances may be less desirable targets for more extensive study.
These results are also important for figuring out how planets form, scientists say.
“Did these planets form in their current positions or migrate toward their host stars from farther out? Understanding the abundances of molecules such as water helps us answer those questions,” Zellem said.
“This paper is an exciting step forward for the study of exoplanets and comparing their properties,” said Mark Swain, study co-author and group supervisor for the exoplanet discovery and science group at JPL.
Michael Line of the University of California, Santa Cruz, also contributed to the study. Other co-authors from JPL included Gael Roudier, Graca Rocha and John Livingston.
Over three billion years ago, Mars had water. A lot more water than it has now.
Oceans of water, in fact. In a studypublished inScientific Reportstoday, researchers found evidence of two large tsunami deposits on Mars, probably caused by large meteorites slamming into the early Martian ocean.
In addition to a massive wave of water, tsunamis carry along huge amounts of debris, some of which can be swept inland and left far beyond the shorelines. In this case, the waves created by the impacts were likely almost 400 feet high, and travelled hundreds of miles inland, carrying debris and scarring the landscape.
The two tsunamis on Mars likely occurred about 3 million years apart, enough time for the Martian climate to cool considerably. During the icy conditions of the second tsunami, large chunks of ice were likely pushed along, carried away from the ocean and left on the dry, cold surface. Researchers hope that eventually, those deposits could be examined for signs of whether the waters of Mars once had life.
As NASA missions explore our solar system and search for new worlds, they are finding water in surprising places. Water is but one piece of our search for habitable planets and life beyond Earth, yet it links many seemingly unrelated worlds in surprising ways.
“NASA science activities have provided a wave of amazing findings related to water in recent years that inspire us to continue investigating our origins and the fascinating possibilities for other worlds, and life, in the universe,” said Ellen Stofan, chief scientist for the agency. “In our lifetime, we may very well finally answer whether we are alone in the solar system and beyond.”
The chemical elements in water, hydrogen and oxygen, are some of the most abundant elements in the universe. Astronomers see the signature of water in giant molecular clouds between the stars, in disks of material that represent newborn planetary systems, and in the atmospheres of giant planets orbiting other stars.
There are several worlds thought to possess liquid water beneath their surfaces, and many more that have water in the form of ice or vapor. Water is found in primitive bodies like comets and asteroids, and dwarf planets like Ceres. The atmospheres and interiors of the four giant planets — Jupiter, Saturn, Uranus and Neptune — are thought to contain enormous quantities of the wet stuff, and their moons and rings have substantial water ice.
Perhaps the most surprising water worlds are the five icy moons of Jupiter and Saturn that show strong evidence of oceans beneath their surfaces: Ganymede, Europa and Callisto at Jupiter, and Enceladus and Titan at Saturn.
Scientists using NASA’s Hubble Space Telescope recently provided powerful evidence that Ganymede has a saltwater, sub-surface ocean, likely sandwiched between two layers of ice.
Europa and Enceladus are thought to have an ocean of liquid water beneath their surface in contact with mineral-rich rock, and may have the three ingredients needed for life as we know it: liquid water, essential chemical elements for biological processes, and sources of energy that could be used by living things. NASA’s Cassini mission has revealed Enceladus as an active world of icy geysers. Recent research suggests it may have hydrothermal activity on its ocean floor, an environment potentially suitable for living organisms.
NASA spacecraft have also found signs of water in permanently shadowed craters on Mercury and our moon, which hold a record of icy impacts across the ages like cryogenic keepsakes.
While our solar system may seem drenched in some places, others seem to have lost large amounts of water.
On Mars, NASA spacecraft have found clear evidence that the Red Planet had water on its surface for long periods in the distant past. NASA’s Curiosity Mars Rover discovered an ancient streambed that existed amidst conditions favorable for life as we know it.
More recently, NASA scientists using ground-based telescopes were able to estimate the amount of water Mars has lost over the eons. They concluded the planet once had enough liquid water to form an ocean occupying almost half of Mars’ northern hemisphere, in some regions reaching depths greater than a mile (1.6 kilometers). But where did the water go?
It’s clear some of it is in the Martian polar ice caps and below the surface. We also think much of Mars’ early atmosphere was stripped away by the wind of charged particles that streams from the sun, causing the planet to dry out. NASA’s MAVEN mission is hard at work following this lead from its orbit around Mars.
The story of how Mars dried out is intimately connected to how the Red Planet’s atmosphere interacts with the solar wind. Data from the agency’s solar missions — including STEREO, Solar Dynamics Observatory and the planned Solar Probe Plus — are vital to helping us better understand what happened.
Understanding the distribution of water in our solar system tells us a great deal about how the planets, moons, comets and other bodies formed 4.5 billion years ago from the disk of gas and dust that surrounded our sun. The space closer to the sun was hotter and drier than the space farther from the sun, which was cold enough for water to condense. The dividing line, called the “frost line,” sat around Jupiter’s present-day orbit. Even today, this is the approximate distance from the sun at which the ice on most comets begins to melt and become “active.” Their brilliant spray releases water ice, vapor, dust and other chemicals, which are thought to form the bedrock of most worlds of the frigid outer solar system.
Scientists think it was too hot in the solar system’s early days for water to condense into liquid or ice on the inner planets, so it had to be delivered — possibly by comets and water-bearing asteroids. NASA’s Dawn mission is currently studying Ceres, which is the largest body in the asteroid belt between Mars and Jupiter. Researchers think Ceres might have a water-rich composition similar to some of the bodies that brought water to the three rocky, inner planets, including Earth.
The amount of water in the giant planet Jupiter holds a critical missing piece to the puzzle of our solar system’s formation. Jupiter was likely the first planet to form, and it contains most of the material that wasn’t incorporated into the sun. The leading theories about its formation rest on the amount of water the planet soaked up. To help solve this mystery, NASA’s Juno mission will measure this important quantity beginning in mid-2016.
Looking further afield, observing other planetary systems as they form is like getting a glimpse of our own solar system’s baby pictures, and water is a big part of that story. For example, NASA’s Spitzer Space Telescope has observed signs of a hail of water-rich comets raining down on a young solar system, much like the bombardment planets in our solar system endured in their youth.
With the study of exoplanets — planets that orbit other stars — we are closer than ever to finding out if other water-rich worlds like ours exist. In fact, our basic concept of what makes planets suitable for life is closely tied to water: Every star has a habitable zone, or a range of distances around it in which temperatures are neither too hot nor too cold for liquid water to exist. NASA’s planet-hunting Kepler mission was designed with this in mind. Kepler looks for planets in the habitable zone around many types of stars.
Recently verifying its thousandth exoplanet, Kepler data confirm that the most common planet sizes are worlds just slightly larger than Earth. Astronomers think many of those worlds could be entirely covered by deep oceans. Kepler’s successor, K2, continues to watch for dips in starlight to uncover new worlds.
The agency’s upcoming TESS mission will search nearby, bright stars in the solar neighborhood for Earth- and super-Earth-sized exoplanets. Some of the planets TESS discovers may have water, and NASA’s next great space observatory, the James Webb Space Telescope, will examine the atmospheres of those special worlds in great detail.
It’s easy to forget that the story of Earth’s water, from gentle rains to raging rivers, is intimately connected to the larger story of our solar system and beyond. But our water came from somewhere — every world in our solar system got its water from the same shared source. So it’s worth considering that the next glass of water you drink could easily have been part of a comet, or an ocean moon, or a long-vanished sea on the surface of Mars. And note that the night sky may be full of exoplanets formed by similar processes to our home world, where gentle waves wash against the shores of alien seas.
(PRESS RELEASE – NASA): NASA Television will air an event from 1 – 2 p.m. EDT on Tuesday, April 7, featuring leading science and engineering experts discussing the recent discoveries of water and organics in our solar system, the role our sun plays in water-loss in neighboring planets, and our search for habitable worlds among the stars.
The event, which is open to the public, will take place in the Webb Auditorium at NASA Headquarters, 300 E Street SW in Washington.
The panel also will highlight the fundamental questions NASA is working to answer through its cutting-edge science research: Where do we come from? Where are we going? Are we alone?
Panel participants include:
John Grunsfeld, astronaut and Science Mission Directorate associate administrator, NASA Headquarters, Washington
Ellen Stofan, chief scientist, NASA Headquarters
James Green, director of Planetary Science, NASA Headquarters
Jeffery Newmark, interim director of Heliophysics, NASA Headquarters
Paul Hertz, director of Astrophysics, NASA Headquarters
While members of the press can participate by phone, both the media and the public also may ask questions during the event via Twitter using the hashtag #askNASA.
For NASA TV streaming video, schedules and downlink information, visit: