Astrophysical Journal

Scientists Finally Know What Time It Is on Saturn

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Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, Calif. 

JoAnna Wendel 
NASA Headquarters, Washington DC

 

A view from NASA’s Cassini spacecraft shows Saturn’s northern hemisphere in 2016 as that part of the planet nears its northern hemisphere summer solstice. A year on Saturn is 29 Earth years; days only last 10:33:38, according to a new analysis of Cassini data. Credit: NASA/JPL-Caltech/Space Science Institute

 

Using new data from NASA’s Cassini spacecraft, researchers believe they have solved a longstanding mystery of solar system science: the length of a day on Saturn. It’s 10 hours, 33 minutes and 38 seconds. 

The figure has eluded planetary scientists for decades, because the gas giant has no solid surface with landmarks to track as it rotates, and it has an unusual magnetic field that hides the planet’s rotation rate.

The answer, it turned out, was hidden in the rings. 

 

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SPACE-TIME: The Missing Mass Mystery

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By George McGinn
Cosmology and Space Research Institute

 
This illustration shows the three steps astronomers used to measure the universe’s expansion rate to an unprecedented accuracy, reducing the total uncertainty to 2.4 percent. Credits: NASA, ESA, A. Field (STScI), and A. Riess (STScI/JHU)

 

I don’t believe in Dark Matter or Dark Energy. Even the new Dark Flow.

While I would like to think that our cosmologists and physicists got lazy, what I really believe is they just created placeholders, misleading ones at that, but I wholeheartedly agree that we have no idea what they are, do, or if they are even real.
 
I like to watch PBS Space-Time on YouTube, as Host and Physicist Matt O’Dowd* would discuss topics that are relevant today in our field, and there is something for everyone, from the novice to the professionals. And while he sometimes will do numerous episodes, like on Dark Matter and Dark Energy, I don’t always agree with what he’s talking about.
 
But after watching the episode below (it is an older one, but the information is as relevant today as it was when it was reported on), I had to post a reply (which is below) and a short explanation, as I am working on a research paper on Dark Matter, Dark Energy, and the new voodoo science of “Dark Flow,” which I will address in another post here.
 
 

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‘Heartbeat Stars’ Unlocked in New Study

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Written by Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
October 21, 2016 

Heart_Beat_Stars.jpg This artist’s concept depicts ”heartbeat stars,” which have been detected by NASA’s Kepler Space Telescope and others. Image credit: NASA/JPL-Caltech

  

Matters of the heart can be puzzling and mysterious – so too with unusual astronomical objects called heartbeat stars.

Heartbeat stars, discovered in large numbers by NASA’s Kepler space telescope, are binary stars (systems of two stars orbiting each other) that got their name because if you were to map out their brightness over time, the result would look like an electrocardiogram, a graph of the electrical activity of the heart. Scientists are interested in them because they are binary systems in elongated elliptical orbits. This makes them natural laboratories for studying the gravitational effects of stars on each other.

In a heartbeat star system, the distance between the two stars varies drastically as they orbit each other. Heartbeat stars can get as close as a few stellar radii to each other, and as far as 10 times that distance during the course of one orbit.
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NASA, Citizen Scientists Discover Potential New Hunting Ground for Exoplanets

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Artist’s concept of the newly discovered disk. Credits: Jonathan Holden

 

Via a NASA-led citizen science project, eight people with no formal training in astrophysics helped discover what could be a fruitful new place to search for planets outside our solar system – a large disk of gas and dust encircling a star known as a circumstellar disk.

paper, published in The Astrophysical Journal Letters and coauthored by eight citizen scientists involved in the discovery, describes a newly identified red dwarf star, AWI0005x3s, and its warm circumstellar disk, the kind associated with young planetary systems. Most of the exoplanets, which are planets outside our solar system, that have been imaged to date dwell in disks similar to the one around AWI0005x3s.

The disk and its star are located in what is dubbed the Carina association – a large, loose grouping of similar stars in the Carina Nebula approximately 212 light years from our sun. Its relative proximity to Earth will make it easier to conduct follow-on studies.

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Water Vapor Plumes Discovered on Jupiter’s Moon Europa

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Written by George McGinn
Cosmology and Space Research
September 27, 2016 at 4:32pm EST

This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter. Hubble’s ultraviolet sensitivity allowed for the features — rising over 100 miles (160 kilometers) above Europa’s icy surface — to be discerned. The water is believed to come from a subsurface ocean on Europa. The Hubble data were taken on January 26, 2014. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions. Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center


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.

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Light Echoes Gives Clues To Protoplanetary Disk

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This illustration shows a star surrounded by a protoplanetary disk. Material from the thick disk flows along the star’s magnetic field lines and is deposited onto the star’s surface. When material hits the star, it lights up brightly. Credits: NASA/JPL-Caltech

 

Imagine you want to measure the size of a room, but it’s completely dark. If you shout, you can tell if the space you’re in is relatively big or small, depending on how long it takes to hear the echo after it bounces off the wall. 

Astronomers use this principle to study objects so distant they can’t be seen as more than points. In particular, researchers are interested in calculating how far young stars are from the inner edge of their surrounding protoplanetary disks. These disks of gas and dust are sites where planets form over the course of millions of years.

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NASA Team Probes Peculiar Age-Defying Star

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Age_Defying_Star.jpg
An age-defying star designated as IRAS 19312+1950 (arrow) exhibits features characteristic of a very young star and a very old star. The object stands out as extremely bright inside a large, chemically rich cloud of material, as shown in this image from NASA’s Spitzer Space Telescope. A NASA-led team of scientists thinks the star – which is about 10 times as massive as our sun and emits about 20,000 times as much energy – is a newly forming protostar. That was a big surprise because the region had not been known as a stellar nursery before. But the presence of a nearby interstellar bubble, which indicates the presence of a recently formed massive star, also supports this idea. Credits: NASA/JPL-Caltech


For years, astronomers have puzzled over a massive star lodged deep in the Milky Way that shows conflicting signs of being extremely old and extremely young.

Researchers initially classified the star as elderly, perhaps a red supergiant. But a new study by a NASA-led team of researchers suggests that the object, labeled IRAS 19312+1950, might be something quite different — a protostar, a star still in the making.

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Cloudy Days on Exoplanets May Hide Atmospheric Water

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Hot Jupiters, exoplanets around the same size as Jupiter that orbit very closely to their stars, often have cloud or haze layers in their atmospheres. This may prevent space telescopes from detecting atmospheric water that lies beneath the clouds, according to a study in the Astrophysical Journal. Image credit: NASA/JPL-Caltech

 

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.

For more information about the Hubble Space Telescope, visit: www.nasa.gov/hubble.