Tuesday, December 23, 2014

The Top 101 Astronomical Events to Watch for in 2015

The Top 101 Astronomical Events to Watch for in 2015:



Credit:


Star trails over southwest London. Credit: Roger Hutchinson.
Phew! It’s here.

Now in its seventh year of compilation and the second year running on Universe Today, we’re proud to feature our list of astronomical happenings for the coming year. Print it, bookmark it, hang it on your fridge or observatory wall. Not only is this the yearly article that we jokingly refer to as the “blog post it takes us six months to write,” but we like to think of it as unique, a mix of the mandatory, the predictable and the bizarre. It’s not a 10 ten listicle, and not a full-fledged almanac, but something in between.   

A rundown of astronomy for 2015: There’s lots of astronomical action to look forward to in the coming year. 2015 features the minimum number of eclipses that can occur, two lunars and two solars. The Moon also reaches its minimum standstill this coming year, as its orbit runs shallow relative to the celestial equator. The Moon will also occult all naked eye planets except Saturn in 2015, and will occult the bright star Aldebaran 13 times — once during every lunation in 2015. And speaking of Saturn, the rings of the distant planet are tilted an average of 24 degrees and opening to our line of sight in 2015 as they head towards their widest in 2018.

Finally, solar activity is trending downwards in 2015 after passing the sputtering 2014 maximum for solar cycle #24 as we now head towards a solar minimum around 2020.

Our best bets: Don’t miss these fine celestial spectacles coming to a sky near YOU next year:

– The two final total lunar eclipses in the ongoing tetrad, one on April 4th and September 28th.

– The only total solar eclipse of 2015 on March 20th, crossing the high Arctic.

– A fine dusk pairing of the bright planets Jupiter and Venus on July 1st.

– Possible wildcard outbursts from the Alpha Monocerotid and Taurid meteors, and a favorable New Moon near the peak of the August Perseids.

– Possible naked eye appearances by comet Q2 Lovejoy opening 2015 and comet US10 Catalina later in the year.

– The occultation of a naked eye star for Miami by an asteroid on September 3rd.

– A series of fine occultations by the Moon of bright star Aldebaran worldwide.

The rules: The comprehensive list that follows has been lovingly distilled down to the top 101 astronomical events for 2015 worldwide. Some, such as lunar eclipses, are visible to a wide swath of humanity, while others, such as many of the asteroid occultations or the sole total solar eclipse of 2015 happen over remote locales. We whittled the list down to a “Top 101” using the following criterion:

Meteor showers: Must have a predicted ZHR  greater than 10.

Conjunctions: Must be closer than one degree.

Asteroid occultations: Must have a probability ranking better than 90 and occult a star brighter than magnitude +8.

Comets: Must reach a predicted brightness greater than magnitude +10. But remember: comets don’t always read prognostications such as this, and may over or under perform at whim… and the next big one could come by at any time!

Times quoted are geocentric unless otherwise noted, and are quoted in Universal Time in a 24- hour clock format.

These events are meant to merely whet the appetite. Expect ‘em to be expounded on fully by Universe Today as they approach. We linked to the events listed where possible, and provided a handy list of resources that we routinely consult at the end of the article.

Got it? Good… then without further fanfare, here’s the top 101 astronomical events for 2015 in chronological order:



The path of Comet Q2 Lovejoy From January 1st to January 31st.


The path of Comet Q2 Lovejoy from January 1st to January 31st. Created using Starry Night Education software.
January

01- Comet C/2012 Q2 Lovejoy may reach naked eye visibility.

04- The Quadrantid meteors peak at 02:00 UT, favoring northern Europe with an expected ZHR of 120.

04- The Earth reaches perihelion at ~8:00 UT.

14- Mercury reaches greatest evening elongation 18.9 degrees east of the Sun at ~16:00 UT.

17- The moons Io and Europa cast a double shadow on Jupiter from 3:53 to 4:58 UT.

20- Mars passes 0.2 degrees from Neptune at ~20:00 UT.

24- A triple shadow transit of Jupiter’s moons occurs from 6:26 to 6:54 UT.

29- The Moon occults Aldebaran at ~17:31 UT for the Arctic, marking the first of 13 occultations of the star by the Moon in 2015.



The view at 6:40 UT.


The view at 6:40 UT on January 24th, as 3 of Jupiter’s moons cast shadows on to the Jovian cloud tops simultaneously. Created using Starry Night Education software.
February

01- Venus passes 0.8 degrees south of Neptune at ~17:00 UT.

05- Earth crosses through Jupiter’s equatorial plane, marking the middle of occultation and eclipse season for the Galilean moons.

06- Jupiter reaches opposition at ~18:00 UT.

18- A “Black Moon” occurs, in the sense of the third New Moon in a season with four.

22- Venus passes 0.4 degrees south of Mars at 5:00 UT.

24- Mercury reaches greatest morning elongation at 26.7 degrees west of the Sun at 19:00 UT.

25- The Moon occults Aldebaran for northern Europe at 23:26 UT.

Credit: Eclipse-Maps


The path of the only total solar eclipse of 2015, occurring on March 20th. Credit: Michael Zeiler/Eclipse-Maps.
March

01- Geostationary satellite & Solar Dynamics Observatory eclipse season begins on the weeks leading up to the March Equinox.

04- Venus passes 0.1 degrees north of Uranus at ~18:00 UT. This is the closest planet-planet conjunction of 2015.

05- A Minimoon occurs, marking the most distant Full Moon of 2015 at 18:07 UT, just 10 hours from apogee.

11- Mars passes 0.3 degrees north of Uranus at ~16:00 UT.

20- A total solar eclipse occurs over the Arctic centered on 9:47 UT.

20- The March northward equinox occurs at 16:57 UT.

21- The Moon occults Mars for South America at ~22:14 UT.

25- The Moon occults Aldebaran for northwestern North America at ~7:17 UT.



Stellarium


Neith lives… the close passage of Uranus near Venus on March 4th. Credit: Stellarium.
April

04- A total lunar eclipse occurs, centered on 12:01 UT and visible from eastern Asia, the Pacific and the Americas.

08- Mercury passes 0.5 degrees from Uranus at ~11:00 UT.

21- The Moon occults Aldebaran for northern Asia at ~16:57 UT.

22- The Lyrid meteors peak at 24:00 UT, favoring northern Europe with a ZHR of 18.



May

05- The Eta Aquarid meteors peak (time variable), with an estimated ZHR of 55.

07- Mercury reaches greatest evening elongation at 21.2 degrees east of the Sun at 4:00 UT.

19- The Moon occults Aldebaran for northern North America at ~2:53 UT .

20- Comet C/2014 Q1 PanSTARRS may reach binocular visibility.

20- Io and Ganymede both cast shadows on Jupiter from 22:04 to 22:33 UT.

21- Callisto and Europa both cast shadows on Jupiter from 11:26 to 11:59 UT.

23- Saturn reaches opposition at ~1:00 UT.

28- Ganymede and Io both cast shadows on Jupiter from 00:01 to 2:18 UT.

30- Comet 19P/Borrelly may reach binocular visibility.



June

01- The International Space Station reaches full illumination as the June solstice nears, resulting in multiple nightly passes favoring  northern hemisphere observers.

04- Io and Ganymede both cast shadows on Jupiter from 2:54 to 4:13 UT.

05- Venus reaches greatest eastern (dusk) elongation for 2015, 45 degrees from the Sun at 16:00 UT.

10- Asteroid 424 Gratia occults a +6.1 magnitude star at ~15:10 UT for northwestern Australia.

15- The Moon occults Mercury for the South Indian Ocean at ~2:26 UT.

15- Moon occults Aldebaran in the daytime for the high Arctic at ~11:33 UT.

16- Comet C/2014 Q1 PanSTARRS may reach naked eye visibility.

21- The June northward solstice occurs at 10:51 UT.

24- Mercury reaches greatest (morning) elongation at 22.5 degrees west of the Sun at 17:00 UT.



Stellarium


Venus and Jupiter pair together low in the west on July 1st. Credit: Stellarium.
July

01- Venus passes 0.4 degrees from Jupiter at 9:00 UT, marking the closest conjunction of two naked eye planets for 2015.

02- Comet C/2013 US10 Catalina may reach binocular visibility.

06- Earth reaches aphelion at 13:00 UT.

06- Pluto reaches opposition at 15:00 UT, just a week prior to New Horizons’ historic flyby of the distant world.

12- The Moon occults Aldebaran for northeastern Asia ~18:17 UT.

19- The Moon occults Venus for the South Pacific at ~1:07 UT.

25- Asteroid 49 Pales occults a +6.6 magnitude star at 10:55 UT for Mexico.

28- The Delta Aquarids peak (time variable) with a predicted ZHR of 16.

31- A “Blue Moon” occurs, in the sense of the second Full Moon in a given month.



Credit:


The light curve of comet C/2013 US10 Catalina through its peak in 2015. Credit: Seiichi Yoshida’s Weekly Information About Bright Comets.
August

07- Mercury, Jupiter and Regulus pass within a degree of each other over the next few mornings.

08- The Moon occults Aldebaran for central Asia at ~23:45 UT.

13- The Perseid meteors peak from 06:30 to 09:00 UT, with a maximum predicted ZHR of 100 favoring North America.

19- Mars crosses the Beehive Cluster M44.

28- Asteroid 16 Psyche occults a +6.4 magnitude star at ~9:49 UT for Bolivia and Peru.

29- Supermoon 1 of 3 for 2015: The Moon reaches Full at 18:38 UT, 20 hours from Full.



Lunar eclipse


The path of the Moon through the Earth’s shadow on September 28th. Credit: Fred Espenak/NASA/GSFC
September

01- Neptune reaches opposition at ~3:00 UT.

03- Asteroid 112 Iphigenia occults a +3rd magnitude star for Mexico and Miami at ~9:20 UT. This is the brightest star occulted by an asteroid in 2015.

02- Geostationary satellite and SDO eclipse season begins as we approach the September equinox.

04- Mercury reaches its greatest elongation for 2015, at 27 degrees east of the Sun at 8:00 UT in the dusk skies.

05- The Moon occults Aldebaran for northeastern North America at ~5:38 UT.

13- “Shallow point” (also known as the minor lunar standstill) occurs over the next lunation, as the Moon’s orbit reaches a shallow minimum of 18.1 degrees inclination with respect to the celestial equator… the path of the Moon now begins to widen towards 2025.

13- A partial solar eclipse occurs, centered on 6:55 UT crossing Africa and the Indian Ocean.

23- The September southward equinox occurs at 2:29 UT.

25- Mars passes 0.8 degrees from Regulus at ~4:00 UT.

28- A total lunar eclipse occurs centered on 2:48 UT, visible from the Pacific, the Americas and eastern Europe.

28- Supermoon 2 of 3 for 2015: The Moon reaches Full at 2:52 UT, approximately an hour from Full. This marks the closest Full Moon of the year.



Credit


The path of the September 3rd occultation of a +3rd magnitude star by an asteroid over central Mexico and the Florida Keys. Credit: IOTA/Steve Preston.
October

01- Comet C/2013 US10 Catalina may reach naked eye visibility.

02- The Moon occults Aldebaran for the northern Pacific at 13:14 UT.

02- Io and Callisto both cast shadows on Jupiter from 10:26-11:35 UT.

08- The Moon occults Venus for Australia at ~20:32 UT.

11- The Moon occults Mercury for Chile at ~12:00 UT.

12- Uranus reaches opposition at ~3:00 UT.

16- Mercury reaches greatest elongation (morning) 18.1 degrees west of the Sun at 10:00 UT.

17- Mars passes 0.4 degrees from Jupiter at 22:00 UT.

18- Io and Ganymede both cast shadows on Jupiter from 8:45 to 10:10 UT.

21- The Orionid meteors peak (time variable) with a projected ZHR of 15.

25- Venus passes 1 degree from Jupiter ~19:00 UT.

25- Io and Ganymede both cast shadows on Jupiter from 10:37 to 12:51 UT.

27- Supermoon 3 of 3 for 2015: The Moon reaches Full at 12:06 UT, 23 hours from Full.

29- The Moon occults Aldebaran for Europe at ~23:07 UT.



Credit


The Moon occults Aldebaran: the visibility footprint for North America. The dashed line denotes the area in which the event occurs during the daytime. Credit: Occult 4.1.0.11.
November

01- Io and Ganymede both cast shadows on Jupiter from 15:36 to 15:47 UT.

02- Venus passes 0.7 degrees south of Mars at 00:30 UT.

12- Will the 7 year “Taurid fireball meteor shower” produce?

18- The Leonid meteor shower peaks at 04:00 UT, with an estimated ZHR of 15 favoring Europe.

22- Are we in for a once per decade Alpha Monocerotids outburst? The 2015 peak arrives at 4:25 UT, favoring Europe… with a max ZHR = 400+ possible.

26- The Moon occults Aldebaran for North America at ~9:56 UT.

29- Comet C/2013 X1 PanSTARRS may reach binocular visibility.



Occultation


The daytime occultation of Venus by the Moon over North America on December 7th. Credit: Occult 4.1.0.11.
December

01- The International Space Station reaches full illumination as the December solstice nears, resulting in multiple nightly passes favoring the  southern hemisphere.

04- Mercury occults the +3.3 magnitude star Theta Ophiuchi for South Africa at 16:16 UT prior to dusk.

06- The Moon occults Mars for central Africa at ~2:42 UT.

07- The Moon occults Venus in the daytime for North America at ~16:55 UT.

14- The Geminid meteor shower peaks at 18:00 UT, with a ZHR=120 favoring NE Asia.

21- The December southward solstice occurs at 23:03 UT.

23- The Ursid meteor shower peaks at 2:30 UT with a ZHR variable from 10-50 favoring Europe and the Middle East.

23- The Moon occults Aldebaran for Europe and central Asia at ~19:32 UT.

29- Mercury reaches greatest evening elongation at 19.7 degrees east of the Sun at 00:01 UT.

Didn’t see your favorite event on the list? Let us know, and be sure to send in any images of these fine events to Universe Today’s Flickr forum.

Enjoy another exciting year of space and astronomy… we’ll be expounding on these events and more as 2015 unfolds.

Sources:

– Occult 4.0

-Kevin McGill’s outstanding astronomical simulations.

-Greatest Elongations of Mercury and Venus.

-Stellarium

-Starry Night Pro

-Orbitron

-Steve Preston’s asteroid occultation predictions for 2015.

-The USNO forecast of phenomena for 2015.

-Seiichi Yoshida’s Weekly Information About Bright Comets.

-Fred Espenak’s NASA Eclipse web page.

-The American Meteor Society’s 2015 predictions.

-The International Meteor Organization’s 2015 page.

-Fourmilab’s lunar perigee and apogee calculator.



About 

David Dickinson is an Earth science teacher, freelance science writer, retired USAF veteran & backyard astronomer. He currently writes and ponders the universe from Tampa Bay, Florida.
Posted by Nelio Inacio at 2:47 PM 0 comments

NASA’s NuSTAR Scans the Sun with X-ray Vision

NASA’s NuSTAR Scans the Sun with X-ray Vision:



The west limb of the Sun imaged by NuSTAR and SDO shows areas of high-energy x-rays above particularly active regions (NASA/JPL-Caltech/GSFC)


The west limb of the Sun imaged by NuSTAR and SDO reveals areas of high-energy x-rays above particularly active regions (NASA/JPL-Caltech/GSFC)
What if you had x-ray vision like Superman? Or if those funny-looking glasses they advertised in comic books in the 60s actually worked?* Then with those our Sun might look something like this, lighting up with brilliant flares of high-energy x-rays as seen by NASA’s super-sensitive NuSTAR Space Telescope (and with a little help from SDO.)

The NuStar Space Telescope launched into Earth orbit by a Orbital Science Corp. Pegasus rocket, 2012. The Wolter telescope design images throughout a spectral range from 5 to 80 KeV. (Credit: NASA/Caltech-JPL)
The NuStar Space Telescope launched aboard a Orbital Sciences Pegasus rocket, on June 13, 2012. (Credit: NASA/Caltech-JPL)
Of course NASA’s orbiting NuSTAR telescope is not like your typical medical imaging system. Instead of looking for broken bones, NuSTAR (short for Nuclear Spectroscopic Telescope Array) is made to detect high-energy particles blasting across the Universe from exotic objects like supermassive black holes, pulsars, and supernovae.

Read more: Stars Boil Before They Blow Up, Says NuSTAR

But astronomers suggested turning NuSTAR’s gaze upon our own Sun to see what sorts of x-ray activity may be going on there.

“At first I thought the whole idea was crazy,” said Fiona Harrison, a Professor of Physics and Astronomy at Caltech and PI for the NuSTAR mission. “Why would we have the most sensitive high energy X-ray telescope ever built, designed to peer deep into the universe, look at something in our own back yard?”

But as it turns out NuSTAR was able to reveal some very interesting features on the Sun, showing where the corona is being heated to very high temperatures. The image above shows NuSTAR’s first observations, overlaid onto data acquired by NASA’s Solar Dynamics Observatory.

NuSTAR data is shown in green and blue, revealing high-energy emission around – but not exactly aligned with – active regions on the Sun where solar plasma is being heated to more than 3 million degrees. The red represents ultraviolet light captured by SDO and shows material in the solar atmosphere at a slightly cooler 1 million degrees.



The west limb of the Sun imaged by NuSTAR and SDO shows areas of high-energy x-rays near active regions and coronal loops (NASA/JPL-Caltech/GSFC)


The NuSTAR data overlaid on the full disk SDO image, rotated so north on the Sun is up. (NASA/JPL-Caltech/GSFC)
Because the Sun isn’t terribly intense in high energy x-ray output it’s safe to observe it with NuSTAR — it’s not likely to burn out the telescope’s sensors. But what NuSTAR can detect may help astronomers determine the exact mechanisms behind the intense coronal heating that occurs in and above the Sun’s chromosphere. If so-called “nanoflares” — miniature and as-yet-invisible versions of solar flares — are responsible, for instance, NuSTAR might be able to catch them in action for the first time.

Read more: Warm Coronal Loops May Hold the Key to Hot Solar Atmosphere

“NuSTAR will be exquisitely sensitive to the faintest X-ray activity happening in the solar atmosphere, and that includes possible nanoflares,” said David Smith, solar physicist and member of the NuSTAR team at the University of California, Santa Cruz.

In addition NuSTAR could potentially detect the presence of axions in the Sun’s core — hypothesized particles that may make up dark matter in the Universe.

NuSTAR may not be a “solar telescope” per se, but that won’t stop astronomers from using its unique abilities to learn more about the star we intimately share space with.

“NuSTAR will give us a unique look at the Sun, from the deepest to the highest parts of its atmosphere.”

– David Smith, solar physicist, University of California Santa Cruz
Read more in a JPL article here.

*I never did get my box of 100 army men, either. Then again, I may have ordered a few decades too late.



About 

A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!
Posted by Nelio Inacio at 4:27 AM 0 comments

Monday, December 22, 2014

What Does It Mean To Be ‘Star Stuff’?

What Does It Mean To Be ‘Star Stuff’?:



This Chandra image of the Tycho supernova remnant contains new evidence for what triggered the original supernova explosion. Credit: NASA/CXC/Chinese Academy of Sciences/F. Lu et al.


The Tycho supernova remnant. This type of structure is all that remains after a massive star dies, releasing the chemical building blocks of life and planetary systems into space. Credit: NASA/CXC/Chinese Academy of Sciences/F. Lu et al.
At one time or another, all science enthusiasts have heard the late Carl Sagan’s infamous words: “We are made of star stuff.” But what does that mean exactly? How could colossal balls of plasma, greedily burning away their nuclear fuel in faraway time and space, play any part in spawning the vast complexity of our Earthly world? How is it that “the nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies” could have been forged so offhandedly deep in the hearts of these massive stellar giants?

Unsurprisingly, the story is both elegant and profoundly awe-inspiring.

All stars come from humble beginnings: namely, a gigantic, rotating clump of gas and dust. Gravity drives the cloud to condense as it spins, swirling into an ever more tightly packed sphere of material. Eventually, the star-to-be becomes so dense and hot that molecules of hydrogen in its core collide and fuse into new molecules of helium. These nuclear reactions release powerful bursts of energy in the form of light. The gas shines brightly; a star is born.

The ultimate fate of our fledgling star depends on its mass. Smaller, lightweight stars burn though the hydrogen in their core more slowly than heavier stars, shining somewhat more dimly but living far longer lives. Over time, however, falling hydrogen levels at the center of the star cause fewer hydrogen fusion reactions; fewer hydrogen fusion reactions mean less energy, and therefore less outward pressure.

At a certain point, the star can no longer maintain the tension its core had been sustaining against the mass of its outer layers. Gravity tips the scale, and the outer layers begin to tumble inward on the core. But their collapse heats things up, increasing the core pressure and reversing the process once again. A new hydrogen burning shell is created just outside the core, reestablishing a buffer against the gravity of the star’s surface layers.

While the core continues conducting lower-energy helium fusion reactions, the force of the new hydrogen burning shell pushes on the star’s exterior, causing the outer layers to swell more and more. The star expands and cools into a red giant. Its outer layers will ultimately escape the pull of gravity altogether, floating off into space and leaving behind a small, dead core – a white dwarf.



Lower-mass stars like our sun eventually enter a swollen, red giant phase. Ultimately, its outer layers will be thrown off altogether, leaving nothing but a small white dwarf star. Image Credit: ESO/S. Steinhofel


Lower-mass stars like our sun eventually enter a swollen, red giant phase. Ultimately, its outer layers will be thrown off altogether, leaving nothing but a small white dwarf star. Image Credit: ESO/S. Steinhofel
Heavier stars also occasionally falter in the fight between pressure and gravity, creating new shells of atoms to fuse in the process; however, unlike smaller stars, their excess mass allows them to keep forming these layers. The result is a series of concentric spheres, each shell containing heavier elements than the one surrounding it. Hydrogen in the core gives rise to helium. Helium atoms fuse together to form carbon. Carbon combines with helium to create oxygen, which fuses into neon, then magnesium, then silicon… all the way across the periodic table to iron, where the chain ends. Such massive stars act like a furnace, driving these reactions by way of sheer available energy.

But this energy is a finite resource. Once the star’s core becomes a solid ball of iron, it can no longer fuse elements to create energy. As was the case for smaller stars, fewer energetic reactions in the core of heavyweight stars mean less outward pressure against the force of gravity. The outer layers of the star will then begin to collapse, hastening the pace of heavy element fusion and further reducing the amount of energy available to hold up those outer layers. Density increases exponentially in the shrinking core, jamming together protons and electrons so tightly that it becomes an entirely new entity: a neutron star.

At this point, the core cannot get any denser. The star’s massive outer shells – still tumbling inward and still chock-full of volatile elements – no longer have anywhere to go. They slam into the core like a speeding oil rig crashing into a brick wall, and erupt into a monstrous explosion: a supernova. The extraordinary energies generated during this blast finally allow the fusion of elements even heavier than iron, from cobalt all the way to uranium.



Periodic Table of Elements


Periodic Table of Elements. Massive stars can fuse elements up to Iron (Fe), atomic number 26. Elements with atomic numbers 27 through 92 are produced in the aftermath of a massive star’s core collapse.
The energetic shock wave produced by the supernova moves out into the cosmos, disbursing heavy elements in its wake. These atoms can later be incorporated into planetary systems like our own. Given the right conditions – for instance, an appropriately stable star and a position within its Habitable Zone – these elements provide the building blocks for complex life.

Today, our everyday lives are made possible by these very atoms, forged long ago in the life and death throes of massive stars. Our ability to do anything at all – wake up from a deep sleep, enjoy a delicious meal, drive a car, write a sentence, add and subtract, solve a problem, call a friend, laugh, cry, sing, dance, run, jump, and play – is governed mostly by the behavior of tiny chains of hydrogen combined with heavier elements like carbon, nitrogen, oxygen, and phosphorus.

Other heavy elements are present in smaller quantities in the body, but are nonetheless just as vital to proper functioning. For instance, calcium, fluorine, magnesium, and silicon work alongside phosphorus to strengthen and grow our bones and teeth; ionized sodium, potassium, and chlorine play a vital role in maintaining the body’s fluid balance and electrical activity; and iron comprises the key portion of hemoglobin, the protein that equips our red blood cells with the ability to deliver the oxygen we inhale to the rest of our body.

So, the next time you are having a bad day, try this: close your eyes, take a deep breath, and contemplate the chain of events that connects your body and mind to a place billions of lightyears away, deep in the distant reaches of space and time. Recall that massive stars, many times larger than our sun, spent millions of years turning energy into matter, creating the atoms that make up every part of you, the Earth, and everyone you have ever known and loved.

We human beings are so small; and yet, the delicate dance of molecules made from this star stuff gives rise to a biology that enables us to ponder our wider Universe and how we came to exist at all. Carl Sagan himself explained it best: “Some part of our being knows this is where we came from. We long to return; and we can, because the cosmos is also within us. We’re made of star stuff. We are a way for the cosmos to know itself.”



About 

Vanessa earned her bachelor's degree in Astronomy and Physics in 2009 from Wheaton College in Massachusetts. Her credits in astronomy include observing and analyzing eclipsing binary star systems and taking a walk on the theory side as a NSF REU intern, investigating the expansion of the Universe by analyzing its traces in observations of type 1a supernovae. In her spare time she enjoys writing about astrophysics, cosmology, biology, and medicine, making delicious vegetarian meals, taking adventures with her husband and/or Nikon D50, and saving the world.
Posted by Nelio Inacio at 4:56 PM 0 comments

Meteoric Evidence Suggests Mars May Have a Subsurface Reservoir

Meteoric Evidence Suggests Mars May Have a Subsurface Reservoir:



According to recent findings, the water that once existed on Mars' surface could be found underground. Credit: Kevin Gill


According to recent findings, the water that once existed on Mars’ surface could be found underground. Credit: Kevin Gill
It is a scientific fact that water exists on Mars. Though most of it today consists of water ice in the polar regions or in subsurface areas near the temperate zones, the presence of H²O has been confirmed many times over. It is evidenced by the sculpted channels and outflows that still mark the surface, as well as the presence of clay and mineral deposits that could only have been formed by water. Recent geological surveys provide more evidence that Mars’ surface was once home to warm, flowing water billions of years ago.

But where did the water go? And how and when did it disappear exactly? As it turns out, the answers may lie here on Earth, thanks to meteorites from Mars that indicate that it may have a global reservoir of ice that lies beneath the surface.

Together, researchers from the Tokyo Institute of Technology, the Lunar and Planetary Institute in Houston, the Carnegie Institution for Science in Washington and NASA’s Astromaterials Research and Exploration Science Division examined three Martian meteorites. What they found were samples of water that contained hydrogen atoms that had a ratio of isotopes distinct from that found in water in Mars’ mantle and atmosphere.



Mudstone formations in the Gale Crater show the flat bedding of sediments deposited at the bottom of a lakebed. Credit: NASA/JPL-Caltech/MSSS


Mudstone formations in the Gale Crater show the flat bedding of sediments deposited at the bottom of a lakebed. Credit: NASA/JPL-Caltech/MSSS
This new study examined meteors obtained from different periods in Mars’ past. What the researchers found seemed to indicate that water-ice may have existed beneath the crust intact over long periods of time.

As Professor Tomohiro told Universe Today via email, the significance of this find is that “the new hydrogen reservoir (ground ice and/or hydrated crust) potentially accounts for the “missing” surface water on Mars.”

Basically, there is a gap between what is thought to have existed in the past, and what is observed today in the form of water ice. The findings made by Tomohiro and the international research team help to account for this.

“The total inventory of “observable” current surface water (that mostly occurs as polar ice, ~10E6 km3) is more than one order magnitude smaller than the estimated volume of ancient surface water (~10E7 to 10E8 km3) that is thought to have covered the northern lowlands,” said Tomohiro. “The lack of water at the surface today was problematic for advocates of such large paleo-ocean and -lake volume.”



Meteorites from Mars, like NWA 7034 (shown here), contain evidence of Mars' watery past. Credit: NASA


Meteorites from Mars, like NWA 7034 (shown here), contain evidence of Mars’ watery past. Credit: NASA
In their investigation, the researchers compared the water, hydrogen isotopes and other volatile elements within the meteorites. The results of these examinations forced them to consider two possibilities: In one, the newly identified hydrogen reservoir is evidence of a near-surface ice interbedded with sediment. The second possibility, which seemed far more likely, was that they came from hydrated rock that exists near the top of the Martian crust.

“The evidence is the ‘non-atmospheric’ hydrogen isotope composition of this reservoir,” Tomohiro said. “If this reservoir occurs near the surface, it should easily interact with the atmosphere, resulting in “isotopic equilibrium”.  The non-atmospheric signature indicates that this reservoir must be sequestered elsewhere of this red planet, i.e. ground-ice.”

While the issue of the “missing Martian water” remains controversial, this study may help to bridge the gap between Mars supposed warm, wet past and its cold and icy present. Along with other studies performed here on Earth – as well as the massive amounts of data being transmitted from the many rover and orbiters operating on and in orbit of the planet – are helping to pave the way towards a manned mission, which NASA plans to mount by 2030.

The team’s findings are reported in the journal Earth and Planetary Science Letters.

Further Reading: NASA



About 

Author, freelance writer, educator, Taekwon-Do instructor, and loving hubby, son and Island boy!
Posted by Nelio Inacio at 4:54 PM 0 comments

The Milky Way’s New Neighbor May Tell Us Things About the Universe

The Milky Way’s New Neighbor May Tell Us Things About the Universe:



This dwarf spheroidal galaxy in the constellation Fornax is a satellite of our Milky Way and is one of 10 used in Fermi's dark matter search. The motions of the galaxy's stars indicate that it is embedded in a massive halo of matter that cannot be seen. Credit: ESO/Digital Sky Survey 2


Dwarf spheroidal galaxies, like this one seen in the constellation Fornax, may exist in greater numbers than previously thought. Credit: ESO/Digital Sky Survey 2
As part of the Local Group, a collection of 54 galaxies and dwarf galaxies that measures 10 million light years in diameter, the Milky Way has no shortage of neighbors. However, refinements made in the field of astronomy in recent years are leading to the observation of neighbors that were previously unseen. This, in turn, is changing our view of the local universe to one where things are a lot more crowded.

For instance, scientists working out of the Special Astrophysical Observatory in Karachai-Cherkessia, Russia, recently found a previously undetected dwarf galaxy that exists 7 million light years away. The discovery of this galaxy, named KKs3, and those like it is an exciting prospect for scientists, since they can tell us much about how stars are born in our universe.The Russian team, led by Prof Igor Karachentsev of the Special Astrophysical Observatory (SAO), used the Hubble Space Telescope Advanced Camera for Surveys (ACS) to locate KKs3 in the southern sky near the constellation of Hydrus. The discovery occurred back in August 2014, when they finalized their observations a series of stars that have only one ten-thousandth the mass of the Milky Way.

Such dwarf galaxies are far more difficult to detect than others due to a number of distinct characteristics. KKs3 is what is known as a dwarf spheroid (or dSph) galaxy, a type that has no spiral arms like the Milky Way and also suffers from an absence of raw materials (like dust and gas). Since they lack the materials to form new stars, they are generally composed of older, fainter stars.

Image of the KKR 25 dwarf spheroid galaxy obtained by the Special Astrophysical Observatory using the HST. Credit: SAO RAS/Hubble
Image of the KKR 25 dwarf spheroid galaxy obtained by the Special Astrophysical Observatory using the HST. Credit: SAO RAS
In addition, these galaxies are typically found in close proximity to much larger galaxies, like Andromeda, which appear to have gobbled up their gas and dust long ago. Being faint in nature, and so close to far more luminous objects, is what makes them so tough to spot by direct observation.

Team member Prof Dimitry Makarov, also of the Special Astrophysical Observatory, described the process: “Finding objects like Kks3 is painstaking work, even with observatories like the Hubble Space Telescope. But with persistence, we’re slowly building up a map of our local neighborhood, which turns out to be less empty than we thought. It may be that are a huge number of dwarf spheroidal galaxies out there, something that would have profound consequences for our ideas about the evolution of the cosmos.”

Painstaking is no exaggeration. Since they are devoid of materials like clouds of gas and dust fields, scientists are forced to spot these galaxies by identifying individual stars. Because of this, only one other isolated dwarf spheroidal has been found in the Local Group: a dSph known as KKR 25, which was also discovered by the Russian research team back in 1999.

But despite the challenges of spotting them, astronomers are eager to find more examples of dSph galaxies. As it stands, it is believed that these isolated spheroids must have been born out of a period of rapid star formation, before the galaxies were stripped of their dust and gas or used them all up.

Studying more of these galaxies can therefore tell us much about the process star formation in our universe. The Russian team expects that the task will become easier in the coming years as the James Webb Space Telescope and the European Extremely Large Telescope begin service.

Much like the Spitzer Space Telescope, these next-generation telescopes are optimized for infrared detection and will therefore prove very useful in picking out faint stars. This, in turn, will also give us a more complete understanding of our universe and all that it holds.

Further Reading: Royal Astronomical Society



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Comet Q2 Lovejoy Set to Ring in the New Year: Reader Images and More

Comet Q2 Lovejoy Set to Ring in the New Year: Reader Images and More:



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A fine capture of Comet Q2 Lovejoy on December 21st from Dunedin, New Zealand. Credit and Copyright: Ian Griffin (@Iangriffin)
Keeping warm? Yesterday marked the start of astronomical winter for the northern hemisphere, meaning long nights and (hopefully) clear, cold skies. But we’ve also got another reason to brave the cold this week, as Comet C/2014 Q2 Lovejoy is set to put on a show for northern hemisphere observers.(...)

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Friday, December 19, 2014

Astrophotos: Views of the Geminid Meteor Shower from Around the World

Astrophotos: Views of the Geminid Meteor Shower from Around the World:



A stunning moment captured as a Geminid meteor over Mt. Fuji is reflected in Lake Saiko on December 14, 2014. Credit and copyright: Yuga Kurita.


A stunning moment captured as a Geminid meteor over Mt. Fuji is reflected in Lake Saiko on December 14, 2014. Credit and copyright: Yuga Kurita.
It’s nice to know that not everyone around the world was plagued by clouds, dense fog, driving rain and snowstorms like we had in Minnesota during this year’s Geminid Meteor Shower (and all that weather was within one 24-hour period!) In fact, some astrophotographers were able to capture some stunning views of the Geminids, like this absolutely gorgeous shot of a meteor over Mt. Fuji in Japan.

“I’ve captured Fuji with meteors many times in the past,” said photographer Yuga Kurita. “So I went ambitious this time. I tried to capture Fuji and a meteor reflected in Lake Saiko with a standard focal length lens. When I saw this meteor, I was absolutely stunned.”

See more Geminids from around the world, below:




Geminid meteors over Beijing, China. A stacked image of more than 20 meteors, taken in just 140 minutes. Credit and copyright: Steed Yu.


Geminid meteors over Beijing, China. A stacked image of more than 20 meteors, taken in just 140 minutes. Credit and copyright: Steed Yu.


Geminid Meteor on 12-15-2014 .Captured cutting through the winter Milkyway in the constellation of Auriga, you can see the very colorful trail of the meteor in this image, the trail stretched more than 15 degrees of sky. Taken near Warrenton, Virginia. Credit and copyright: John Chumack.


Geminid Meteor on 12-15-2014 .Captured cutting through the winter Milkyway in the constellation of Auriga, you can see the very colorful trail of the meteor in this image, the trail stretched more than 15 degrees of sky. Taken near Warrenton, Virginia. Credit and copyright: John Chumack.


Four different Geminid meteors as seen from Oxfordshire, England with a Canon 1100D with standard lens. The time of the meteor is marked on the photo. Credit and copyright: Mary Spicer.


Four different Geminid meteors as seen from Oxfordshire, England with a Canon 1100D with standard lens. The time of the meteor is marked on the photo. Credit and copyright: Mary Spicer.
Astrophotographer Mary Spicer shared these four meteor shots, and added, “Over about 90 minutes we saw a total of 61 meteors, 57 of which were Geminids and 6 were fireballs.”



In a 3.5 hour period on Dec. 13/14, 2014, the photographer managed to capture 38 Geminid meteors. This composite contains just 11 of those meteors. Credit and copyright: Paul Andrew.


In a 3.5 hour period on Dec. 13/14, 2014, the photographer managed to capture 38 Geminid meteors. This composite contains just 11 of those meteors. Credit and copyright: Paul Andrew.
A timelapse movie taken by Michael Mauldin of the clouds and stars over Liberty Hill, Texas on Saturday, December 13, 2014. Two Geminid meteors are captured (each frame is frozen for a few seconds so you can see them):





Geminid meteors caught over Connaught Dome, at the Norman Lockyer Observatory in Devon, England. Credit and copyright: David Strange.


Geminid meteors caught over Connaught Dome, at the Norman Lockyer Observatory in Devon, England. Credit and copyright: David Strange.


Two Geminid meteors — one especially bright — streak through the sky on Sunday, December 14, 2014. This photo is a composite of two separate frames, taken a few minutes apart, to capture both meteors. Credit and copyright: David Murr.


Two Geminid meteors — one especially bright — streak through the sky on Sunday, December 14, 2014. This photo is a composite of two separate frames, taken a few minutes apart, to capture both meteors. Credit and copyright: David Murr.


A Geminid fireball captured on Dec. 13, 2014 near Cabo Rojo, Puerto Rico. Credit and copyright: Frankie Lucena.


A Geminid fireball captured on Dec. 13, 2014 near Cabo Rojo, Puerto Rico. Credit and copyright: Frankie Lucena.


A faint green Geminid meteor joined in the sky scene with On display are : M44, Jupiter , the Moon, and Procyon in Canis Minor. Credit and copyright: Carsten Pauer.


A faint green Geminid meteor joined in the sky scene with On display are : M44, Jupiter , the Moon, and Procyon in Canis Minor. Credit and copyright: Carsten Pauer.


A unique view of the 2014 Geminid Meteor Shower, taken on Dec. 14. 5 images stacked. Credit and copyright: Jason Asplin.


A unique view of the 2014 Geminid Meteor Shower, taken on Dec. 14. 5 images stacked. Credit and copyright: Jason Asplin.


A Geminid Meteor taken on Dec. 14, 2014 from a garden in the middle of Worthing, West Sussex England. Credit and copyright: BiteYourBum.com Photography.


A Geminid Meteor
taken on Dec. 14, 2014 from a garden in the middle of Worthing, West Sussex England. Credit and copyright: BiteYourBum.com Photography.


A bright Geminid meteor on Dec. 14, 2014. Credit and copyright: Slave Stojanoski.


A bright Geminid meteor on Dec. 14, 2014. Credit and copyright: Slave Stojanoski.


Waiting for Geminids: a self portrait of the photographer waiting for the meteor shower to peak. Credit and copyright: Sergio Garcia Rill.


Waiting for Geminids: a self portrait of the photographer waiting for the meteor shower to peak. Credit and copyright: Sergio Garcia Rill.
While the above photo doesn’t have any meteors, it still garners a place in this post because astrophotographer Sergio Garcia Rill was waiting and hoping to capture some. Alas, writes Rill on Flickr, “While I had good enough luck to get some relatively clear skies for the Geminids meteor shower I think I wasn’t fortunate enough to catch any meteors on camera. I saw about a dozen meteors with my eyes, and a couple in the direction my cameras were pointing, but they probably weren’t strong enough to get captured with the settings I had.”

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Gallery: Saturn Moons Show How Not To Be Seen In Cassini Images

Gallery: Saturn Moons Show How Not To Be Seen In Cassini Images:



Tethys is mostly obscured behind Rhea as the moons orbit Saturn. The picture was captured by the Cassini spacecraft in April 2012 and highlighted in December 2014. Credit: NASA/JPL-Caltech/Space Science Institute


Tethys is mostly obscured behind Rhea as the moons orbit Saturn. The picture was captured by the Cassini spacecraft in April 2012 and highlighted in December 2014. Credit: NASA/JPL-Caltech/Space Science Institute
Peekaboo! Tethys makes a (mostly in vain) attempt to hide behind Rhea in this picture taken by the Cassini spacecraft a couple of years ago, but highlighted by NASA in a recent picture essay. Besides the neat view of the orbital dance, one thing that is clearly visible between the two moons is the different colors — a product of their different surfaces. It turns out that Tethys’ bright surface is due to geysers from another moon.

“Scientists believe that Tethys’ surprisingly high albedo is due to the water ice jets emerging from its neighbor, Enceladus,” NASA stated. “The fresh water ice becomes the E ring [of Saturn] and can eventually arrive at Tethys, giving it a fresh surface layer of clean ice.”

Saturn has an astounding number of moons — 62 moons discovered so far, and 53 of them named, if you don’t count the spectacular ring that surrounds the planet. The collection of celestial bodies includes Titan, the second-biggest moon in the Solar System. It’s so big that it includes a thick atmosphere. (Ganymede, around Jupiter, is the biggest.)

Below are some other pictures of moons dancing around Saturn — some harder to spot than others. All images were taken by the Cassini spacecraft since it arrived at the planet in 2004.



Titan peeks from behind two of Saturn's rings. Another small moon Epimetheus, appears just above the rings. Credit: NASA/JPL/Space Science Institute


Titan peeks from behind two of Saturn’s rings. Another small moon Epimetheus, appears just above the rings. Credit: NASA/JPL/Space Science Institute


Saturn's moons Dione and Rhea appear conjoined in this optical illusion-like image taken by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute


Saturn’s moons Dione and Rhea appear conjoined in this optical illusion-like image taken by the Cassini spacecraft. Credit: NASA/JPL/Space Science Institute


Saturn's rings, made dark in part as the planet casts its shadow across them, cut a striking figure before Saturn's largest moon, Titan. Credit: NASA/JPL/Space Science Institute


Saturn’s rings, made dark in part as the planet casts its shadow across them, cut a striking figure before Saturn’s largest moon, Titan. Credit: NASA/JPL/Space Science Institute


Three of Saturn's moons bunch together in this image by Cassini. Credit: NASA/JPL/Space Science Institute. Click for larger image.


Three of Saturn’s moons bunch together in this image by Cassini. Credit: NASA/JPL/Space Science Institute. Click for larger image.


Saturns rings with Saturns moon Mimas in the foreground (credit: NASA)


Saturn’s rings with Saturn’s moon Mimas in the foreground (credit: NASA)


Titan and Tethys line up for a portrait of 'sibling' moons. Credit: NASA/JPL/Space Science Institute


Titan and Tethys line up for a portrait of ‘sibling’ moons. Credit: NASA/JPL/Space Science Institute


About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
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Morning Star, We Hardly Knew Ya: Venus Express’ Best Discoveries In 8 Years

Morning Star, We Hardly Knew Ya: Venus Express’ Best Discoveries In 8 Years:



Artist's impression of Venus Express entering orbit in 2006. Credit: ESA - AOES Medialab


Artist’s impression of Venus Express entering orbit in 2006. Credit: ESA – AOES Medialab
Venus Express is mostly dead. The spacecraft spent more than eight years faithfully relaying information from the Morning Star/Evening Star planet, but it’s now out of fuel, out of control and within weeks of burning up in the atmosphere.

While we mourn the end of the productive mission, the European Space Agency spacecraft showed us a lot about the planet that we once considered a twin to Earth. Some of the surprises, as you can see below, including a possibly slowing-down rotation, and the realization that volcanoes may still be active on the hellish planet.



False colour composite of a rainbow-like feature known as a ‘glory’, seen on Venus on 24 July 2011. The image is composed of three images at ultraviolet, visible, and near-infrared wavelengths from the Venus Monitoring Camera. The images were taken 10 seconds apart and, due to the motion of the spacecraft, do not overlap perfectly. The glory is 1200 km across, as seen from the spacecraft, 6000 km away. It's the only glory ever seen on another planet. Credit: ESA/MPS/DLR/IDA.


False color composite of a rainbow-like feature known as a ‘glory’, seen on Venus on 24 July 2011. The image is composed of three images at ultraviolet, visible, and near-infrared wavelengths from the Venus Monitoring Camera. The images were taken 10 seconds apart and, due to the motion of the spacecraft, do not overlap perfectly. The glory is 1200 km across, as seen from the spacecraft, 6000 km away. It’s the only glory ever seen on another planet. Credit: ESA/MPS/DLR/IDA.


Quick video summary: Venus Express found that the spacecraft’s rotation may have slowed down by 6.5 minutes between 1996 (when the Magellan spacecraft was in orbit) and 2012. The surprising information emerged when scientists discovered surface features weren’t in the expected areas, and couldn’t find any calculation errors between the data.



Animation of Venus’ southern polar vortex made from VIRTIS thermal infrared images; white is cooler clouds at higher altitudes. Credit: ESA/VIRTIS-VenusX/INAF-IASF/LESIA-Obs. de Paris (G. Piccioni, INAF-IASF)


Quick video summary: Volcanic flows may still be active on Venus’ surface, according to 2010 data from the mission. Scientists looked at surface areas that had not been “weathered” very much (indicating that they are relatively young) and detected at least nine spots where the heat in those zones is much higher than the areas around it.



Venus Express picture of clouds on the planet. Despite the planet being extremely hot, the spacecraft found a cold layer in the atmosphere at temperatures of about -175 degrees Celsius (-283 Fahrenheit) that is colder than anything on Earth. It's so chilling that carbon dioxide may freeze and fall as snow or ice. Credit: ESA/MPS/DLR/IDA


A picture of Venus’ clouds. Despite the planet being extremely hot, Venus Express found a cold layer in the atmosphere at temperatures of about -175 degrees Celsius (-283 Fahrenheit) that is colder than anything on Earth. It’s so chilling that carbon dioxide may freeze and fall as snow or ice. Credit: ESA/MPS/DLR/IDA


Artist's impression of Venus with the solar wind flowing around the planet, which has little magnetic protection. Venus Express found that a lot of water has bled into space over the years from the planet, which happens when the sun's ultraviolet radiation breaks oxygen and hydrogen molecules apart and pushes them into space. Credit: ESA - C. Carreau


Artist’s impression of Venus with the solar wind flowing around the planet, which has little magnetic protection. Venus Express found that a lot of water has bled into space over the years from the planet, which happens when the sun’s ultraviolet radiation breaks oxygen and hydrogen molecules apart and pushes them into space. Credit: ESA – C. Carreau


About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
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