Archive

Archive for May 12, 2015

NASA Research Reveals Europa’s Mystery Dark Material Could Be Sea Salt


 Image Credit: NASA/JPL-Caltech/SETI Institute

Image Credit: NASA/JPL-Caltech/SETI Institute

NASA laboratory experiments suggest the dark material coating some geological features of Jupiter’s moon Europa is likely sea salt from a subsurface ocean, discolored by exposure to radiation. The presence of sea salt on Europa’s surface suggests the ocean is interacting with its rocky seafloor — an important consideration in determining whether the icy moon could support life.

The study is accepted for publication in the journal Geophysical Research Letters and is available online.

“We have many questions about Europa, the most important and most difficult to answer being is there life? Research like this is important because it focuses on questions we can definitively answer, like whether or not Europa is inhabitable,” said Curt Niebur, Outer Planets Program scientist at NASA Headquarters in Washington. “Once we have those answers, we can tackle the bigger question about life in the ocean beneath Europa’s ice shell.”

Link To Full Story

Advertisements

Delta Cephei’s Hidden Companion


Bow shock around star Delta Cephei. Credit: NASA/JPL-Caltech/M

Bow shock around star Delta Cephei. Credit: NASA/JPL-Caltech/M

To measure distances in the universe, astronomers use cepheids, a family of variable stars whose luminosity varies with time. Their role as distance calibrators has brought them attention from researchers for more than a century. While it was thought that nearly everything was known about the prototype of cepheids, named Delta Cephei, a team of researchers at the University of Geneva (UNIGE), the Johns Hopkins University, and the European Space Agency (ESA), have now discovered that this star has a hidden companion. They have published an article about the discovery in The Astrophysical Journal.

Delta Cephei, prototype of the cepheids, which has given its name to all similar variable stars, was discovered 230 years ago by the English astronomer John Goodricke. Since the early 20th century, scientists have been interested in measuring cosmic distances using a relationship between these stars’ periods of pulsation and their luminosities (intrinsic brightness), discovered by the American Henrietta Leavitt. Today, researchers from the Astronomical Observatory of UNIGE, Johns Hopkins University and the ESA show that Delta Cephei is, in fact, a double star, made up of a cepheid-type variable star and a companion that had thus far escaped detection, probably because of its low luminosity. Yet, pairs of stars, called binaries, complicate the calibration of the period-luminosity relationship, and can bias the measurement of distances. This is a surprising discovery, since Delta Cephei is one of the most studied stars, of which scientists thought they knew almost everything.

Link To Full Story

Weather On Alien Worlds Uncovered: Cloudy Mornings & Hot Afternoons

May 12, 2015 1 comment

TORONTO, May 12, 2015 — We may complain a lot about the weather on earth but perhaps we are much better off here than on some alien worlds, where the daily forecast is cloudy, overcast skies in the morning and scorching heat in the afternoon.

A team of international astronomers including York University scientist Professor Ray Jayawardhana have uncovered evidence of daily weather cycles on six extra-solar planets using sensitive observations from the Kepler space telescope.

“Despite the discovery of thousands of extra-solar planets, what these far-off worlds look like is still shrouded in mystery,” says lead author Lisa Esteves, graduate student at the University of Toronto.

In their paper entitled “Changing Phases of Alien Worlds: Probing Atmospheres of Kepler Planets with High-Precision Photometry” published today in the Astrophysical Journal, the team analyzed all 14 Kepler planets known to exhibit phase variations, and found indications of cloudy mornings on four and hot, clear afternoons on two others.

Link To Full Story