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Carnival of Space #570

universetoday - 2018. július 18. 21:55

This week’s Carnival of Space is hosted by Brian Wang at his Next Big Future blog.

Click here to read Carnival of Space #570

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to susie@wshcrew.space, and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

The post Carnival of Space #570 appeared first on Universe Today.

NASA’s James Webb Space Telescope will Inspect the Atmospheres of Distant Gas Giants

universetoday - 2018. július 18. 21:30

The James Webb Space Telescope is like the party of the century that keeps getting postponed. Due to its sheer complexity and some anomalous readings that were detected during vibration testing, the launch date of this telescope has been pushed back many times – it is currently expected to launch sometime in 2021. But for obvious reasons, NASA remains committed to seeing this mission through.

Once deployed, the JWST will be the most powerful space telescope in operation, and its advanced suite of instruments will reveal things about the Universe that have never before been seen. Among these are the atmospheres of extra-solar planets, which will initially consist of gas giants. In so doing, the JWST will refine the search for habitable planets, and eventually begin examining some potential candidates.

The JWST will be doing this in conjunction with the Transiting Exoplanet Survey Satellite (TESS), which deployed to space back in April of 2018. As the name suggests, TESS will be searching for planets using the Transit Method (aka. Transit Photometry), where stars are monitored for periodic dips in brightness – which are caused by a planet passing in front of them relative to the observer.

Artist concept of the Transiting Exoplanet Survey Satellite and its 4 telescopes. Credit: NASA/MIT

Some of Webb’s first observations will be conducted through the Director’s Discretionary Early Release Science program –  a transiting exoplanet planet team at Webb’s science operation center. This team is planning on conducting three different types of observations that will provide new scientific knowledge and a better understanding of Webb’s science instruments.

As Jacob Bean of the University of Chicago, a co-principal investigator on the transiting exoplanet project, explained in a NASA press release:

“We have two main goals. The first is to get transiting exoplanet datasets from Webb to the astronomical community as soon as possible. The second is to do some great science so that astronomers and the public can see how powerful this observatory is.”

As Natalie Batalha of NASA Ames Research Center, the project’s principal investigator, added:

“Our team’s goal is to provide critical knowledge and insights to the astronomical community that will help to catalyze exoplanet research and make the best use of Webb in the limited time we have available.”

For their first observation, the JWST will be responsible for characterizing a planet’s atmosphere by examining the light that passes through it. This happens whenever a planet transits in front of a star, and the way light is absorbed at different wavelengths provides clues as to the atmosphere’s chemical composition. Unfortunately, existing space telescopes have not had the necessary resolution to scan anything smaller than a gas giant.

https://exoplanets.nasa.gov/5-ways-to-find-a-planet/vid/transit_method_single_planet.mp4

The JWST, with its advanced infrared instruments, will examine the light passing through exoplanet atmospheres, split it into a rainbow spectrum, and then infer the atmospheres’ composition based on which sections of light are missing. For these observations, the project team selected WASP-79b, a Jupiter-sized exoplanet that orbits a star in the Eridanus constellation, roughly 780 light-years from Earth.

The team expects to detect and measure the abundances of water, carbon monoxide, and carbon dioxide in WASP-79b, but is also hoping to find molecules that have not yet been detected in exoplanet atmospheres. For their second observation, the team will be monitoring a “hot Jupiter” known as WASP-43b, a planet which orbits its star with a period of less than 20 hours.

Like all exoplanets that orbit closely to their stars, this gas giant is tidally-locked – where one side is always facing the star. When the planet is in front of the star, astronomers are only able to see its cooler backside; but as it orbits, the hot day-side slowly comes into view. By observing this planet for the entirety of its orbit, astronomers will be able to observe those variations (known as a phase curve) and use the data to map the planet’s temperature, clouds, and atmospheric chemistry.

This data will allow them to sample the atmosphere to different depths and obtain a more complete picture of the planet’s internal structure. As Bean indicated:

“We have already seen dramatic and unexpected variations for this planet with Hubble and Spitzer. With Webb we will reveal these variations in significantly greater detail to understand the physical processes that are responsible.”

An exoplanet about ten times Jupiter’s mass located some 330 light years from Earth. X-ray: NASA/CXC/SAO/I.Pillitteri et al; Optical: DSS; Illustration: NASA/CXC/M.Weiss

For their third observation, the team will be attempting to observe a transiting planet directly. This is very challenging, seeing as how the star’s light is much brighter and therefore obscures the faint light being reflected off the planet’s atmosphere. One method for addressing this is to measure the light coming from a star when the planet is visible, and again when it disappears behind the star.

By comparing the two measurements, astronomers can calculate how much light is coming from the planet alone. This technique works best for very hot planets that glow brightly in infrared light, which is why they selected WASP-18b for this observation – a hot Jupiter that reaches temperatures of around 2,900 K (2627 °C; 4,800 °F). In the process, they hope to determine the composition of the planet’s smothering stratosphere.

In the end, these observations will help test the abilities of the JWST and calibrate its instruments. The ultimate goal will be to examine the atmospheres of potentially-habitable exoplanets, which in this case will include rocky (aka. “Earth-like”) planets that orbit low mass, dimmer red dwarf stars. In addition to being the most common star in our galaxy, red dwarfs are also believed to be the most likely place to find Earth-like planets.

NASA’s James Webb Telescope, shown in this artist’s conception, will provide more information about previously detected exoplanets. Beyond 2020, many more next-generation space telescopes are expected to build on what it discovers. Credit: NASA

As Kevin Stevenson, a researcher with the Space Telescope Science Institute and a co-principal investigator on the project, explained:

“TESS should locate more than a dozen planets orbiting in the habitable zones of red dwarfs, a few of which might actually be habitable. We want to learn whether those planets have atmospheres and Webb will be the one to tell us. The results will go a long way towards answering the question of whether conditions favorable to life are common in our galaxy.”

The James Webb Space Telescope will be the world’s premier space science observatory once deployed, and will help astronomers to solve mysteries in our Solar System, study exoplanets, and observe the very earliest periods of the Universe to determine how its large-scale structure evolved over time. For this reason, its understandable why NASA is asking that the astronomical community be patient until they are sure it will deploy successfully.

When the payoff is nothing short of ground-breaking discoveries, it’s only fair that we be willing to wait. In the meantime, be sure to check out this video about how scientists study exoplanet atmospheres, courtesy of the Space Telescope Science Institute:

Further Reading: NASA

The post NASA’s James Webb Space Telescope will Inspect the Atmospheres of Distant Gas Giants appeared first on Universe Today.

Billion-year-old lake deposit yields clues to Earth's ancient biosphere

sciencedaily.com - 2018. július 18. 19:48
A sample of ancient oxygen, teased out of a 1.4-billion-year-old evaporative lake deposit in Ontario, provides fresh evidence of what the Earth's atmosphere and biosphere were like during the interval leading up to the emergence of animal life.

Solar corona is more structured, dynamic than previously thought

sciencedaily.com - 2018. július 18. 18:48
Scientists have discovered never-before-detected, fine-grained structures in the Sun's outer atmosphere, or corona. The team imaged this critical region in detail using sophisticated software techniques and longer exposures from the COR-2 camera on board NASA's Solar and Terrestrial Relations Observatory-A (STEREO-A).

Enter the Red Planet: Our Guide to Mars Opposition 2018

universetoday - 2018. július 18. 18:04

A dusty view of Mars from July 11th as Mars opposition 2018 nears. Image credit and copyright: Waskogm.

Have you checked out Mars this season? Mars reaches opposition on July 27th at 5:00 Universal Time (UT) shining at magnitude -2.8 and appearing 24.3” across—nearly as large as it can appear, and the largest since the historic opposition of 2003. We won’t have an opposition this favorable again until September 15th, 2035.

Mars starts this week near the +4th magnitude star Psi Capricorni, loops westward through retrograde briefly into the astronomical constellation of Sagittarius the Archer in late August before heading back into Capricornus in September.

Mars opened up 2018 just 4.8” across, trekking through the early dawn sky. What a difference a few months make: Mars broke 15” arc seconds—a maximum size for an unfavorable opposition near aphelion—on May 30th, and now dominates the summer sky around midnight.

The path of Mars from July through September 2018. Credit: Starry Night.

There’s one downside, however, to the 2018 opposition of Mars: it’s occurring very nearly as far south along the ecliptic as it can. This is great news for observers in Australia, South Africa and South America, as the Red Planet rides high near the zenith at local midnight. Up north, however, we are still looking at Mars through the murk of the atmosphere lower to the horizon. For example, here in Norfolk, Virginia at latitude 37 degrees north, we never see Mars rise more than 29 degrees altitude above the southern horizon this season.

Down with Dust Storms

Does Mars seem a bit… peachy colored to you this season? It’s not your imagination: a planetary dust storm is indeed underway. It’s the middle of autumn for northern hemisphere of Mars, and this seems to be shaping up to be one of those oppositions where the planet, though at its closest, presents a featureless, dust-shrouded disk. This seems to be the case roughly every third opposition or so… our best hope now is that it may clear in the coming final weeks of July. We checked out Mars over the past weekend, and could just spy the pole cap and some slight detail under a veil of haze.

The Curiosity rover’s dusty view from late June. Credit: NASA

Despite the depiction of Martian dust storms in science fiction blockbusters such as The Martian as furious and unrelenting, these storms are actually pretty mild-mannered, barely able to chase a leaf before them through the tenuous Martian atmosphere, if deciduous trees grew on Mars. One thing Martian dust storms can do, however, is coat solar panels with a battery-killing film, and it has yet to be seen if the aging Opportunity rover will awaken and phone home from Meridiani Planum.

Unlike the Earth, Mars has a markedly elliptical orbit, varying from 1.7 (AU) astronomical units from the Sun at aphelion to 1.4 AU near perihelion. This all means that not every opposition of Mars is equal; in fact, Mars can range from 55 million to 102 million kilometers from the Earth near opposition and appear 13.8” to 25.1” across, depending on where it’s at in its orbit. And although Mars laps the Earth roughly every 26 months, a cycle of favorable oppositions repeat every 15 years.

Still dusty… Mars from July 16th. Image credit and copyright: Shahrin Ahmad.

In 2018, Mars reaches opposition on July 27th at 5:00 UT/1:00 AM EDT 57.8 million kilometers from the Earth, then makes its closest approach four days later on July 31st at 8:00 UT/4:00 AM EDT, 57.6 million kilometers distant. Why the discrepancy? Well, opposition is simply reckoned as the point where an outer planet reaches an ecliptic longitude of 180 degrees opposite from the Sun. Mars, however, is still headed inward towards perihelion on September 16th, while Earth just came off of aphelion on July 6th.

Visually, Mars can on occasion “go yellow” and present a saffron color even to the naked eye if a planetary wide sandstorm is underway. At the eyepiece, the most prominent feature is always the pole cap, a white dollop on the planet’s pumpkin hued limb. Crank up the magnification, and dark patches come into view, as Mars is the only planet in the solar system presenting an actual surface available for amateur scrutiny. Mars has a day very similar to Earth’s at only 37 minutes longer in duration, meaning that if you observe Mars at the same time every evening, you’ll see nearly the same longitude of the planet turned towards you, shifted 10 degrees westward. A great tool for comparing what features on Mars are currently turned Earthward is Mars Previewer.

Can you spy Mars… daytime? This month is a good time to try, as it currently shines brighter than Jupiter. The easiest thing to do is lock on to it with a telescope near dawn as it sets to the west and the Sun rises in the east, then simply track it into the daytime sky. We’ve seen Mars in 2003 and again this year while the Sun is still above the horizon… having the Moon nearby also helps, though of course, Mars is very close to the horizon at sunset/sunrise right at opposition.

And speaking of which, viewers in Europe, Africa, Asia and Australia are in for a special treat on the evening of July 27th, as a total eclipse of the Moon occurs just 15 hours after Mars passes opposition. Ironically, this is also a Minimoon eclipse, as the Moon also passes apogee just 14 hours prior to entering the Earth’s shadow. Expect to see the Red Planet just seven degrees from the blood red Moon at mid-eclipse (more on the eclipse next week).

Mars versus the total lunar eclipse on the night of July 27th. Credit: Stellarium

The Moon won’t occult (pass in front of) Mars again until November 16th, 2018 for the very southernmost tip of South America. Stick around until July 26th, 2344 AD, and you can witness the Moon occulting the planet Saturn during an eclipse, though you’ll have to journey to southern Japan to do it.

But you may not have to wait that long… stick around until April 27th, 2078, and you can witness the Moon occult Mars… during a penumbral lunar eclipse:

The April 27th, 2078 occultation of Mars… during a penumbral lunar eclipse. Credit: NASA/GSFC/Occult 4.2/Starry Night

This current evening apparition of Mars ends over a year from now on September 2nd, 2019, as Mars reaches solar conjunction on the farside of the Sun.

Finally, opposition is a great time to try and check the tiny Martian moons Phobos and Deimos off of your life list. These two moons were actually discovered by Asaph Hall from the United States Naval Observatory’s newly installed 26-inch refractor during a favorable parihelic apparition of Mars in 1877.

An alien sky… Phobos occults Deimos as seen from the surface of Mars, courtesy of the Curiosity rover. NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ

Shining at magnitude +12.4 (Deimos) and +11.3 (Phobos), seeing these moons would be a cinch… were it not for the presence of Mars shining a million times brighter nearby. Your best bet is to construct an occulting bar eyepiece (we’ve used a thin strip of foil and a guitar string affixed to an eyepiece to accomplish this) or simply place brilliant Mars just out of view. Phobos orbits once every 7.7 hours and substends 20” from the disk of Mars, while Deimos goes around Mars once every 30.35 hours and journeys 66” with each elongation from the Martian disk. PDS rings node or a good planetarium program such as Starry Night or Stellarium will show the current orientation of the Martian moons, aiding in your decision of whether or not to take up the quest.

Don’t miss out on Mars this opposition season… it’ll be almost another two decades before we get another favorable view.

Read all about viewing the planets, from observation to imaging and sketching in our new book: The Universe Today Guide to the Cosmos out October 23rd, now available for pre-order.

The post Enter the Red Planet: Our Guide to Mars Opposition 2018 appeared first on Universe Today.

X-ray data may be first evidence of a star devouring a planet

sciencedaily.com - 2018. július 18. 17:33
An analysis of X-ray data suggests the first observations of a star swallowing a planet, and may also explain the star's mysterious dimming.

Planck: Final data from the mission lends support to the standard cosmological model

sciencedaily.com - 2018. július 18. 16:47
With its increased reliability and its data on the polarization of relic radiation, the Planck mission corroborates the standard cosmological model with unrivaled precision for these parameters, even if some anomalies still remain.

Finding a planet with a 10 year orbit in just a few months

sciencedaily.com - 2018. július 18. 15:25
To discover the presence of a planet around stars, astronomers wait until it has completed three orbits. However, this effective technique has its drawbacks since it cannot confirm the presence of planets at relatively long periods. To overcome this obstacle, astronomers have developed a method that makes it possible to ensure the presence of a planet in a few months, even if it takes 10 years to circle its star.

Supersharp images from new VLT adaptive optics

sciencedaily.com - 2018. július 18. 14:22
ESO's Very Large Telescope (VLT) has achieved first light with a new adaptive optics mode called laser tomography -- and has captured remarkably sharp test images of the planet Neptune and other objects. The MUSE instrument working with the GALACSI adaptive optics module, can now use this new technique to correct for turbulence at different altitudes in the atmosphere. It is now possible to capture images from the ground at visible wavelengths that are sharper than those from the NASA/ESA Hubble Space Telescope.

PHYSICIST REPORT 285: HOW DO SOLAR WIND PARTICLES GET INTO THE EARTHS MAGNETOSPHERE?

napkitores.hu - 2018. július 18. 13:30
CONTRIBUTIONS or DONATIONS FOR OUR PHYSICIST: https://www.paypal.me/PLANETXNEWS Planet X News Online Store: ...

NASA’s Juno Mission Spots Another Possible Volcano on Jupiter’s Moon Io

universetoday - 2018. július 18. 05:23

When the Juno spacecraft arrived in orbit around Jupiter in 2016, it became the second spacecraft in history to study Jupiter directly – the first being the Galileo probe, which orbited Jupiter between 1995 and 2003. With every passing orbit (known as a perijove, which take place every 53 days), the spacecraft has revealed more about Jupiter’s atmosphere, weather patterns, and magnetic environment.

In addition, Juno recently discovered something interesting about Jupiter’s closest orbiting moon Io. Based on data collected by its Jovian InfraRed Auroral Mapper (JIRAM) instrument, Juno detected a new heat source close to the south pole of Io that could indicate the presence of a previously undiscovered volcano. This is just the latest discovery made by the probe during its mission, which NASA recently extended to 2021.

Annotated image of the new heat source in the southern hemisphere of the Jupiter moon Io. Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

The infrared data was collected on Dec. 16th, 2017, when the Juno spacecraft was about 470,000 km (290,000 mi) away from Io. As Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics (INAF) in Rome, explained in a recent NASA press release:

“The new Io hotspot JIRAM picked up is about 200 miles (300 kilometers) from the nearest previously mapped hotspot. We are not ruling out movement or modification of a previously discovered hot spot, but it is difficult to imagine one could travel such a distance and still be considered the same feature.”

Aside from Juno and Galileo, many NASA missions have visited or passed through the Jovian System in the past few decades. These have including the Pioneer 10 and 11 missions in 1973/74, the Voyager 1 and 2 missions in 1979, and the Cassini and New Horizons missions in 2000 and 2007, respectively. Each of these missions managed to snap pictures of the Jovians moons on their way to the outer Solar System.

Annotated image of the new heat source close to the south pole of Io, with a scale depicting the range of temperatures displayed in the infrared image. Credits: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

Combined with ground-based observations, scientists have accounted for over 150 volcanoes on the surface of Io so far, with estimates claiming there could over 400 in total. Since it entered Jupiter’s orbit on July 4th, 2016, the Juno probe has traveled nearly 235 million km (146 million mi) from one pole to other. On July 16th, Juno will conduct its 13th perijove maneuver, once again passing low over Jupiter’s cloud tops at a distance of about 3,400 km (2,100 mi).

During these flybys, Juno probes beneath the upper atmosphere to study the planet’s auroras to learn more about it’s structure, atmosphere and magnetosphere. By shedding light on these characteristics, the Juno probe will also teach us more about the planet’s origins and evolution. This in turn will teach scientists a great deal more about the formation and evolution of our Solar System, and perhaps how life began here.

Further Reading: NASA

The post NASA’s Juno Mission Spots Another Possible Volcano on Jupiter’s Moon Io appeared first on Universe Today.

Jupiter’s Moons: 10 More Found, 79 Known

skyandtelescope.com-MostRecent - 2018. július 17. 23:25

Over the past 18 months, astronomers have painstakingly tracked a dozen tiny moons that they found circling the giant planet Jupiter.

The post Jupiter’s Moons: 10 More Found, 79 Known appeared first on Sky & Telescope.

Scientists recover possible fragments of meteorite that landed in marine sanctuary

sciencedaily.com - 2018. július 17. 21:51
The largest recorded meteorite to strike the United States in 21 years fell into NOAA's Olympic Coast National Marine Sanctuary, and researchers have recovered what are believed to be pieces of the dense, interstellar rock after conducting the first intentional hunt for a meteorite at sea.
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