Tuesday, February 3, 2015

What Was The Impact That Killed The Dinosaurs?

What Was The Impact That Killed The Dinosaurs?:

Artist's conception of an asteroid crashing into the Yucatan Peninsula about 65 million years ago. Credit: Donald E. Davis/NASA


Artist’s conception of an asteroid crashing into the Yucatan Peninsula about 65 million years ago. Credit: Donald E. Davis/NASA
What suddenly made the dinosaurs disappear 65 million or 66 million years ago? Whatever it was, all indications show that it was a massive extinction event. The fossil record not only shows dinosaurs disappearing, but also numerous other species of the era. Whatever it was, there was a sudden change in the environment that changed evolution forever.

The leading theory for this change is a small body (likely an asteroid or a comet) that slammed into Mexico’s Yucatan Peninsula. The impact’s force generated enough debris to block the Sun worldwide, killing any survivors of starvation.

The crater

There have been numerous theories proposed for the dinosaurs’ death, but in 1980 more evidence arose for a huge impact on the Earth. This happened when a father-son University of California, Berkeley research team — Luis Alvarez and Walter Alvarez — discovered a link with a 110-mile (177-kilometer) wide impact crater near the Yucatan coast of Mexico. It’s now known as Chicxulub.

Chicxulub crater in Mexico. Credit: Wikipedia/NASA


Chicxulub crater in Mexico. Credit: Wikipedia/NASA
It sounds surprising that such a huge crater wasn’t found until that late, especially given satellites had been doing Earth observation for the better part of 20 years at that point. But as NASA explains, “Chicxulub … eluded detection for decades because it was hidden (and at the same time preserved) beneath a kilometer of younger rocks and sediments.”

The data came from a Mexican company that was seeking oil in the region. The geologists saw the structure and guessed, from its circular shape, that it was an impact crater. Further observations were done using magnetic and gravity data, NASA said, as well as space observations (including at least one shuttle mission).

The layer

The asteroid’s impact on Earth was quite catastrophic. Estimated at six miles (9.7 kilometers) wide, it carved out a substantial amount of debris that spread quickly around the Earth, aided by winds in the atmosphere.

What Killed The Dinosaurs


K-T Boundary. Image Credit: NASA Earth Observatory
If you look in the fossil record all over the world, you will see a layer that is known as the “K-T Boundary”, referring to the boundary between the Cretaceous and Tertiary periods in geologic history. This layer, says the University of California, Berkeley, is made up of “glassy spheres or tektites, shocked quartz and a layer of iridium-enriched dust.”

Of note, iridium is a rare element on the surface of the Earth, but it’s fairly common in meteorites. (Some argue that the iridium could have come from volcanic eruptions churning it up from inside the Earth; for more information, see this Universe Today story.)

Was it simply ‘the last straw’?

While an asteroid (or comet) striking the Earth could certainly cause all the catastrophic events listed above, some scientists believe the dinosaurs were already on their last legs (so to speak) before the impact took place. Berkeley points to “dramatic climate variation” in the million years preceding the event, such as very cold periods in the tropical environment that the dinosaurs were used to.

Impactors strike during the reign of the dinosaurs (image credit: MasPix/devianart)


Impactors strike during the reign of the dinosaurs (image credit: MasPix/devianart)
What might have caused this were several volcanic eruptions in India around the same time. Some scientists believe it was the volcanic eruptions themselves that caused the extinction and that the impact was not principally to blame, since the eruptions could also have produced the iridium layer. But Berkeley’s Paul Renne said the eruptions were more a catalyst for weakening the dinosaurs.

“These precursory phenomena made the global ecosystem much more sensitive to even relatively small triggers, so that what otherwise might have been a fairly minor effect shifted the ecosystem into a new state,” Renne stated in 2013. “The impact was the coup de grace.”

Here on Universe Today there are several articles on the asteroids and the Chicxulub Crater. Astronomy Cast has an episode on asteroids as bad neighbors.



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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Posted by Nelio Inacio at 2:26 PM 0 comments

Jupiter and the Full Snow Moon Come Together In a Beautiful Conjunction Tonight

Jupiter and the Full Snow Moon Come Together In a Beautiful Conjunction Tonight:

A halo rings the bright moon and planet Jupiter (left of moon) last night Feb. 2. Ice crystals in high clouds like cirrostratus refract moonlight into a circle of light. Tonight the Full Snow Moon will shine just 4.5° from the planet. Credit: Bob King


A halo rings the bright moon and planet Jupiter (left of moon) last night Feb. 2. Ice crystals in high clouds like cirrostratus refract moonlight into a circle of light. Tonight the Full Snow Moon will shine just 4.5° from the planet. Credit: Bob King
The Full Moon celebrates Jupiter’s coming opposition by accompanying the bright planet in a beautiful conjunction tonight.

Even last night Jupiter and the Moon were close enough to attract attention. Tonight they’ll be even more striking. Two reasons for that. The Moon is full this evening and will have crept within 41/2° of the planet. They’ll rise together and roll together all night long.

The Full Snow Moon will share the sky with Jupiter in Cancer tonight not far from the Sickle or head of Leo the Lion. The map shows the scene around 8 o'clock local time. Source: Stellarium


The Full Snow Moon will share the sky with Jupiter in Cancer tonight not far from the Sickle or head of Leo the Lion. The map shows the scene around 8 o’clock local time. Source: Stellarium
February’s full moon is aptly named the Full Snow Moon as snowfall can be heavy this month. Just ask the folks in Chicago. The Cherokee Indians called it the “Bone Moon”, named for the tough times experienced by many Native Americans in mid-winter when food supplies ran low. With little left to eat people made use of everything including bones and bone marrow for soup.

Not only is the Full Moon directly opposite the Sun in the sky, rising around sunset and setting around sunrise, but in mid-winter they’re nearly on opposite ends of the celestial seesaw.

Jupiter, like tonight's Full Moon, will be directly opposite the Sun this Friday and in "full moon" phase. Credit: Bob King


Jupiter, like tonight’s Full Moon, will be directly opposite the Sun this Friday and in “full moon” phase. Because both planets are lined up on the same side of the Sun, Jupiter will also be at its closest to us for the year. Credit: Bob King
In early February the Sun is still near its lowest point in the sky (bottom of the seesaw) for the northern half of  the globe. And while daylight is steadily increasing as the Sun moves northward, darkness still has the upper hand this month. Full Moons like tonight’s lie 180° opposite the Sun, placing the Moon near the top of the seesaw. Come early August, the Sun will occupy the Moon’s spot and the Full Moon will have slid down to the Sun’s current position. Yin and Yang folks.

Now here’s the interesting thing. Jupiter will also be in “full moon” phase when it reaches opposition this Friday Feb. 6.  Take a look at the diagram. From our perspective on Earth, Jupiter and the Sun lie on opposite sides of our planet 180° apart. As the Sun sets Friday, Jupiter will rise in the east and remain visible all night until setting around sunrise exactly like a Full Moon.

So in a funny way, we have two Full Moons this week only one’s a planet.

Like me, a lot of you enjoy a good moonrise. That golden-orange globe, the crazy squished appearance at rising and the transition to the bright, white, beaming disk that throws enough light on a winter night to ski in the forest without a headlamp. All good reasons to be alive.

If Jupiter were moved to the Moon's distance it would span about 20 of sky or 40x the apparent diameter of the Full Moon. Credit: Roscosmos with additions by the author


If Jupiter were moved to the Moon’s distance it would span about 20 degrees or 40 times the apparent diameter of the Full Moon. Credit: Roscosmos with additions by the author
To find when the moon rises for your town, click over to this moonrise calculator. As you step outside tonight to get your required Moon and Jupiter-shine, consider the scene if we took neighboring Jupiter and placed it at the same distance as the Moon. A recent series of such scenes was released by the Russian Federal Space Agency (Roscosmos). I included one here and added the Moon for you to compare. Is Jupiter enormous or what?



About 

I'm a long-time amateur astronomer and member of the American Association of Variable Star Observers (AAVSO). My observing passions include everything from auroras to Z Cam stars. Every day the universe offers up something both beautiful and thought-provoking. I also write a daily astronomy blog called Astro Bob.

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Posted by Nelio Inacio at 2:24 PM 0 comments

Gravitational Waves from Early Universe Remain Elusive

Gravitational Waves from Early Universe Remain Elusive:


Color scale image from Planck



A joint analysis of data from Planck and the ground-based experiment BICEP2 has found no conclusive evidence of gravitational waves from the birth of our universe.






Posted by Nelio Inacio at 2:23 PM 0 comments

Saturday, January 31, 2015

Moroccan Meteorite May Be a 4.4-Billion-Year-Old Chunk of Dark Martian Crust

Moroccan Meteorite May Be a 4.4-Billion-Year-Old Chunk of Dark Martian Crust:

Global mosaic of Mars showing the dark basaltic Syrtis Major Planus region made from Viking Orbiter images. (NSSDC)


Global mosaic of Mars showing the dark basaltic Syrtis Major Planus region made from Viking Orbiter images. (NSSDC)
Mars is often referred to as the Red Planet. But its signature color is only skin-deep – or, I should say, dust-deep. Beneath its rusty regolith Mars has many other hues and shades as well, from pale greys like those found inside holes drilled by Curiosity to large dark regions that are the result of ancient lava flows. Now, researchers think we may have an actual piece of one of Mars’ dark plains here on Earth in the form of a meteorite that was found in the Moroccan desert in 2011.

Mars meteorite NWA 7034 (NASA)


Mars meteorite NWA 7034 (NASA)
Classified as NWA 7034 (for Northwest Africa) the meteorite is a 320-gram (11 oz.) piece of Martian basaltic breccia made up of small fragments cemented together in a dark matrix. Nicknamed “Black Beauty,” NWA 7034 is one of the oldest meteorites ever discovered and is like nothing else ever found on Earth.

According to a new study on a fragment of the meteorite by researchers from Brown University in Providence, Rhode Island and the University of New Mexico, Black Beauty is a 4.4-billion-year-old chunk of Mars’ dark crust – the only known piece of such to have landed on Earth.

While other meteorites originating from Mars have been identified, they are of entirely different types than Black Beauty.

The researchers used a hyperspectral imaging technique to obtain data from across the whole fragment. In doing this, the measurements matched what’s been detected from Mars orbit by NASA’s Mars Reconnaissance Orbiter.

“Other techniques give us measurements of a dime-sized spot,” said Kevin Cannon, a Brown University graduate student and lead author of a new paper published in the journal Icarus. “What we wanted to do was get an average for the entire sample. That overall measurement was what ended up matching the orbital data.”

In addition to indicating a truly ancient piece of another planet, these findings hint at what the surface of many parts of Mars might be like just below the rusty soil… a surface that’s been shattered and reassembled many times by meteorite impacts.

“This is showing that if you went to Mars and picked up a chunk of crust, you’d expect it to be heavily beat up, battered, broken apart and put back together,” Cannon said.

HiRISE image of dark terrain near Ganges Chasma (NASA/JPL/University of Arizona)


HiRISE image of dark terrain near Ganges Chasma (NASA/JPL/University of Arizona)
Source/read more at Brown University news.



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!

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The Nile River and Delta Is the Longest River In The World

What Is the Longest River In The World?:

The Nile River and Delta, viewed at night by the Expedition 25 crew on Oct. 28, 2010. Credit: NASA


The Nile River and Delta, viewed at night by the Expedition 25 crew on Oct. 28, 2010. Credit: NASA
Planet Earth boasts some very long rivers, all of which have long and honored histories. The Amazon, Mississippi, Euphrates, Yangtze, and Nile have all played huge roles in the rise and evolution of human societies. Rivers like the Danube, Seine, Volga and Thames are intrinsic to the character of some of our most major cities.

But when it comes to the title of which river is longest, the Nile takes top billing. At 6,583 km (4,258 miles) long, and draining in an area of 3,349,000 square kilometers, it is the longest river in the world, and even the longest river in the Solar System. It crosses international boundaries, its water is shared by 11 African nations, and it is responsible for the one of the greatest and longest-lasting civilizations in the world.

Officially, the Nile begins at Lake Victoria – Africa’s largest Great Lake that occupies the border region between Tanzania, Uganda and Kenya – and ends in a large delta and empties into the Mediterranean Sea. However, the great river also has many tributaries, the greatest of which are the Blue Nile and White Nile rivers.

The White Nile is the source of the majority of the Nile’s water and fertile soil, and originates from Africa’s Great Lakes region of Central Africa (a group that includes Lake Victoria, Edward, Tanganyika, etc.). The Blue Nile starts at Lake Tana in Ethiopia, and flows north-west to where it meets the Nile near Khartoum, Sudan.

Nile Delta from space by the MODIS sensor on the Terra satellite. Credit: Jacques Descloitres/NASA/GSFC


Nile Delta from space by the MODIS sensor on the Terra satellite.
Credit: Jacques Descloitres/NASA/GSFC
The northern section of the Nile flows entirely through the Sudanese Desert to Egypt. Historically speaking, most of the population and cities of these two countries were built along the river valley, a tradition which continues into the modern age. In addition to the capitol cities of Juba, Khartoum, and Cairo, nearly all the cultural and historical sites of Ancient Egypt are to be found along the riverbanks.

The Nile was a much longer river in ancient times. Prior to the Miocene era (ca. 23 to 5 million years ago), Lake Tangnayika drained northwards into the Albert Nile, making the Nile about 1,400 km. That portion of the river became blocked by the bulk of the formation of the Virunga Mountains through volcanic activity.

Between 8000 and 1000 B.C.E., there was also a third tributary called the Yellow Nile that connected the highlands of eastern Chad to the Nile River Valley. Its remains are known as the Wadi Howar, a riverbed that passes through the northern border of Chad and meets the Nile near the southern point of the Great Bend  – the region that lies between Khartoum and Aswan in southern Egypt where the river protrudes east and west before traveling north again.

The Nile, as it exists today, is thought to be the fifth river that has flowed from the Ethiopian Highlands. Some form of the Nile is believed to have existed for 25 million years. Satellite images have been used to confirm this, identifying dry watercourses to the west of the Nile that are believed to have been the Eonile.

Lake Moeris and Faiyum Oasis, as seen from space, south-west of the Nile Delta and Cairo. Credit: Earth Snapshot


Lake Moeris and Faiyum Oasis, as seen from space, south-west of the Nile Delta and Cairo. Credit: Earth Snapshot
This “ancestral Nile” is believed to be what flowed in the region during the later Miocene, transporting sedimentary deposits to the Mediterranean Sea. During the late-Miocene Era, the Mediterranean Sea became a closed basin and evaporated to the point of being empty or nearly so. At this point, the Nile cut a new course down to a base level that was several hundred meters below sea level.

This created a very long and deep canyon which was filled with sediment, which at some point raised the riverbed sufficiently for the river to overflow westward into a depression to create Lake Moeris southwest of Cairo. A canyon, now filled by surface drift, represents an ancestral Nile called the Eonile that flowed during the Miocene.

Due to their inability to penetrate the wetlands of South Sudan, the headwaters of the Nile remained unknown to Greek and Roman explorers. Hence, it was not until 1858 when John Speke sighted Lake Victoria that the source of the Nile became known to European historians. He reached its southern shore while traveling with Richard Burton on an expedition to explore central Africa and locate the African Great Lakes.

The Temple of Luxor, Egypt, one of the most important ancient Egyptian cultural monuments, located aside the Nile. Credit: Wikipedia/Creative Commons


The Temple of Luxor, one of the most important ancient Egyptian cultural monuments, located in southern Egypt along the Nile. Credit: Wikipedia/Creative Commons
Believing he had found the source of the Nile, he named the lake after Queen Victoria, the then-monarch of the United Kingdom. Upon learning of this, Burton was outraged that Speke claimed to have found the true source of the Nile and a scientific dispute ensued.

This in turn triggered new waves of exploration that sent David Livingstone into the area. However, he failed by pushing too far to the west where he encountered the Congo River. It was not until the Welsh-American explorer Henry Morton Stanley circumvented Lake Victoria during an expedition that ran from 1874 to 1877 that Speke’s claim to have found the source of the Nile was confirmed.

The Nile became a major transportation route during the European colonial period. Many steamers used the waterway to travel through Egypt and south to the Sudan during the 19th century. With the completion of the Suez Canal and the British takeover of Egypt in the 1870s, steamer navigation of the river became a regular occurrence and continued well into the 1960s and the independence of both nations.

Today, the Nile River remains a central feature to Egypt and the Sudan. Its waters are used by all nations that it passes through for irrigation and farming, and its important to the rise and endurance of civilization in the region cannot be underestimated. In fact, the sheer longevity of Egypt’s many ruling dynasties is often attributed by historians to the periodic flows of sediment and nutrients from Lake Victoria to the delta. Thanks to these flows, it is believed, communities along the Nile River never experienced collapse and disintegration as other cultures did.

The Nile is rivaled only by Amazon, which is also the world’s widest river.

If you’d like more info on Earth, check out NASA’s Solar System Exploration Guide on Earth. And here’s a link to NASA’s Earth Observatory.

We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.

Source:
Wikipedia



About 

Author, freelance writer, educator, Taekwon-Do instructor, and loving hubby, son and Island boy!

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Posted by Nelio Inacio at 10:07 AM 0 comments

It Looks Like an Asteroid Strike Can’t Cause a Worldwide, Dinosaur-Killing Firestorm

It Looks Like an Asteroid Strike Can’t Cause a Worldwide, Dinosaur-Killing Firestorm:

Computer generated simulation of an asteroid strike on the Earth. Credit: Don Davis/AFP/Getty Images


Computer generated simulation of an asteroid strike on the Earth. Credit: Don Davis/AFP/Getty Images
For decades, scientists have debated the cause of the mass extinction that wiped out the dinosaurs and other life 65 million years ago. While the majority of researchers agree that a massive asteroid impact at Chicxulub, Mexico is the culprit, there have been some dissenters. Now, new research is questioning just a portion of the asteroid/Cretaceous-Paleogene extinction scenario. While the scientists involved in the study don’t doubt that such an asteroid impact actually happened, their research shows it is just not possible that vast global firestorms could have ravaged our planet and be the main cause of the extinction.



Researchers from the University of Exeter, University of Edinburgh and Imperial College London recreated the vast energy released from a 15-km wide asteroid slamming into Earth, which occurred around the time that dinosaurs became extinct.

They found that close to the impact site — a 180 km wide crater in Mexico — the heat pulse would have lasted for less than a minute. This intense but short-lived heat, the team says, could not have ignited live plants, challenging the idea that the impact led to global firestorms.

However, they did find that the effects of the impact would actually be worse on the other side of the planet, where less intense but longer periods of heat could have ignited live plant matter.

“By combining computer simulations of the impact with methods from engineering we have been able to recreate the enormous heat of the impact in the laboratory,” said Dr. Claire Belcher from the University of Exeter. “This has shown us that the heat was more likely to severely affect ecosystems a long distance away, such that forests in New Zealand would have had more chance of suffering major wildfires than forests in North America that were close to the impact. This flips our understanding of the effects of the impact on its head and means that palaeontologists may need to look for new clues from fossils found a long way from the impact to better understand the mass extinction event.”

The Cretaceous-Paleogene extinction was one of the biggest in Earth’s history and geologic evidence of the impact has been discovered in rock layers around the world from this time period. Some critics of the asteroid impact theory as a cause of the extinction have pointed to some of the microfossils from the Gulf of Mexico that show the impact occurred well before the extinction and could not have been its primary cause. Others point to volcanism that produced the Deccan traps of India around this time as a possible cause of the extinction.

But multiple models have showed such an impact would have instantly caused devastating shock waves, tsunamis, and the release of large amounts of dust, debris and gases that would have led to a low light levels and a prolonged cooling of Earth’s surface. The darkness and a global winter would have decimated the planet life and the dependent animals.

So while fire and brimstone may not have played a big role in the Cretaceous-Paleogene extinction, there was plenty of destruction and mayhem for the resulting extinction of more than 70% of known species.

Here’s a video from the researchers that shows their findings that close to the impact site, the heat pulse was too short to ignite live plant material.



Their research is published in the Journal of the Geological Society.

Source: University Exeter

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Posted by Nelio Inacio at 10:05 AM 0 comments

Friday, January 30, 2015

This Comparison of Comet 67/P With Other Solar System Bodies Will Blow Your Mind

This Comparison of Comet 67/P With Other Solar System Bodies Will Blow Your Mind:

Credit:


Can you see the comet? Four solar system objects adjusted for true brightness counterclockwise from the upper right: Earth, Enceladus, the Moon, and Comet 67/P. Credit: ESA/Rosetta Blog/NASA/JPL/Space Science Institute (Enceladus); ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/ UPM/DASP/IDA and Gordan Ugarkovich (Earth); Robert Vanderbei, Princeton University (Moon); ESA/Rosetta/NAVCAM (67P/C-G).
There’s darkness out there in the cold corners of the solar system.

And we’re not talking about a Lovecraftian darkness, the kind that would summon Cthulhu himself.  We’re talking of celestial bodies that are, well. So black, they make a Spinal Tap album cover blinding by comparison.

We recently came across the above true color comparison of Comet 67/P Churyumov-Gerasimenko adjusted for true reflectivity contrasted with other bodies in the solar system. 67/P is definitely in the “none more black” (to quote Nigel Tufnel) category as compared to, well, nearly everything.

Welcome to the wonderful world of albedo. Bob King wrote a great article last year discussing the albedo of Comet 67/P. The true albedo (or lack thereof) of 67/P as revealed by Rosetta’s NAVCAM continues to astound us. Are all comets this black close up? After all, we’re talking about those same brilliant celestial wonders that can sometimes be seen in the daytime, and are the crimson harbingers of regal change in The Game of Thrones, right?

There was also a great discussion of the dark realms of 67/P in a recent SETI Talk:



As with many things in the universe, it’s all a matter of perspective. If you live in the U.S. Northeast and are busy like we were earlier today digging yourself out from Snowmageddon 2015, then you were enjoying a planetary surface with a high albedo much more akin to Enceladus pictured above. Except, of course, you’d be shoveling methane and carbon dioxide-laced snow on the Saturnian moon… Ice, snow and cloud cover can make a world shinny white and highly reflective. Earthshine on the dark limb of the crescent Moon can even vary markedly depending on the amount of cloud and snow cover on the Earth that’s currently rotated moonward.

Earthshine or the 'Old Moon in the New Moon's arms' from earlier this week. Photo by author.


A brilliant Earthshine, or the ‘Old Moon in the New Moon’s arms’ from earlier last week. Photo by author.
To confound this, apparent magnitude over an extended object is diffused over its surface area, making the coma of a comet or a nebula appear fainter than it actually is. Engineers preparing for planetary encounters must account for changes in light conditions, or their cameras may just record… nothing.

For example, out by Pluto, Charon, and friends, the Sun is only 1/1600th as bright as seen here on sunny Earth. NASA’s New Horizons spacecraft will have to adjust for the low light levels accordingly during its historic flyby this July. On the plus side, Pluto seems to have a respectable albedo of 50% to 65%, and may well turn out to look like Neptune’s large moon, Triton.

Triton as imaged by Voyager 2: a dead ringer for Pluto? Credit: NASA/JPL.


Triton as imaged by Voyager 2: a dead ringer for Pluto? Credit: NASA/JPL.
And albedo has a role in heat absorption and reflection as well, in a phenomenon known as global dimming. The ivory snows of Enceladus have an albedo of over 95%, while gloomy Comet 67/P has an albedo of about 5%, less than that of flat black paint. A common practice here in Aroostook County Maine is to take fireplace ashes and scatter them across an icy driveway. What you’re doing is simply lowering the surface albedo and increasing the absorption of solar energy to help break up the snow and ice on a sunny day.

A high albedo snow cover blanketed New England earlier this week! Photo by author.


A high albedo snow cover blanketed New England earlier this week! Photo by author.
Ever manage to see Venus in the daytime?  We like to point out the Cytherean world in the daytime sky to folks whenever possible, often using the nearby Moon as a guide. Most folks are amazed at how easy this daytime feat of visual athletics actually is, owing to the fact that the cloud tops of Venus actually have a higher albedo of 90%, versus the Moon’s murky 8 to 12%.

Venus (upper left) by daylight. Photo by author.


Venus (upper left) by daylight. Photo by author.
Apollo 12 command module pilot Richard Gordon remarked that astronauts Al Bean and Pete Conrad looked like they’d been “playing in a coal bin” on returning from the surface of the Moon. And in case you’re wondering, Apollo astronauts reported that moondust smelled like ‘burnt gunpowder’ once they’d unsuited.

The surface of the Moon closeup: darker than you think! Credit: Apollo 12/NASA.


The surface of the Moon closeup: darker than you think! Credit: Apollo 12/NASA.
Magnitude, global dimming and planetary albedo may even play a role in SETI as well, as we begin to image Earthlike exoplanets… will our first detection of ET be the glow of their cities on the nightside of their homeworld? Does light pollution pervade the cosmos?

And a grey cosmos awaits interstellar explorers as well. Forget Captain Kirk chasing Khan through a splashy, multi-hued nebula: most are of the light grey to faded green varieties close up. Through a telescope, most nebulae are devoid of color. It’s only when a long time exposure is completed that colors too faint to see with the naked eye emerge.

All strange thoughts to consider as we scout out the dark corners of the solar system. Will the Philae lander reawaken as perihelion for Comet 67/P approaches on August 13th, 2015? Will astronauts someday have to navigate over the dark surface of a comet?

I can’t help but think as I look at the duck-like structure of 67/P that one day, those two great lobes will probably separate in a grand outburst of activity. Heck, Comet 17P/Holmes is undergoing just such an outburst now — one of the best it has generated since 2007 — though it’s still below +10th magnitude. How I’d love to get a look at Comet 17P/Holmes up close, and see just what’s going on!



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.

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Posted by Nelio Inacio at 9:58 AM 0 comments

Astronomers Discover Ancient System with Five Small Planets

Astronomers Discover Ancient System with Five Small Planets:


Kepler-444 Planetary System



The star system Kepler-444 is the oldest known to host terrestrial-sized planets.






Posted by Nelio Inacio at 9:56 AM 0 comments

Thursday, January 29, 2015

Astronomers Catch A Quasar Shutting Off

Astronomers Catch A Quasar Shutting Off:

This artist's rending shows "before" and "after" images of a changing look quasar. Credit: Yale University.


This artist’s rending shows “before” and “after” images of a changing look quasar. Credit: Yale University.
Last week, astronomers at Yale University reported seeing something unusual: a seemingly stedfast beacon from the far reaches of the Universe went quiet. This relic light source, a quasar located in the region of our sky known as the celestial equator, unexpectedly became 6-7 times dimmer over the first decade of the 21st century. Thanks to this dramatic change in luminosity, astronomers now have an unprecedented opportunity to study both the life cycle of quasars and the galaxies that they once called home.

A quasar arises from a distant (and therefore, very old) galaxy that once contained a central, rotating supermassive black hole – what astronomers call an active galactic nucleus. This spinning beast ravenously swallowed up large amounts of ambient gas and dust, kicking up surrounding material and sending it streaming out of the galaxy at blistering speeds. Quasars shine because these ancient jets achieved tremendous energies, thereby giving rise to a torrent of light so powerful that astronomers are still able to detect it here on Earth, billions of years later.

In their hey-day, some active galactic nuclei were also energetic enough to excite electrons farther away from the central black hole. But even in the very early Universe, electrons couldn’t withstand that kind of excitement forever; the laws of physics don’t allow it. Eventually, each electron would drop back down to its rest state, releasing a photon of corresponding energy. This cycle of excitation happened over and over and over again, in regular and predictable patterns. Modern astronomers can visualize those transitions – and the energies that caused them – by examining a quasar’s optical spectrum for characteristic emission lines at certain wavelengths.

An example of an atomic spectrum, showing emission lines at particular wavelengths.


A simple example of an atomic spectrum, showing emission lines at particular wavelengths. Broad humps correspond to brighter emission lines, while lines that arise from narrow, lower-intensity emissions appear dimmer. Credit: NASA
Not all quasars are created equal, however. While the spectra of some quasars reveal many bright, broad emission lines at different energies, other quasars’ spectra consist of only the dim, narrow variety. Until now, some astronomers thought that these variations in emission lines among quasars were simply due to differences in their orientation as seen from Earth; that is, the more face-on a quasar was relative to us, the broader the emission lines astronomers would be able to see.

But all of that has now been thrown into question, thanks to our friend J015957.64+003310.5, the quasar revealed by the team of astronomers at Yale. Indeed, it is now plausible that a quasar’s pattern of emission lines simply changes over its lifetime. After gathering ten years of spectral observations from the quasar, the researchers observed its original change in brightness in 2010. In July 2014, they confirmed that it was still just as dim, disproving hypotheses that suggested the effect was simply due to intervening gas or dust. “We’ve looked at hundreds of thousands of quasars at this point, and now we’ve found one that has switched off,” explained C. Megan Urry, the study’s co-author.

How would that happen, you ask? After observing the comparable dearth of broad emission lines in its spectrum, Urry and her colleagues believe that long ago, the black hole at the heart of the quasar simply went on a diet. After all, an active galactic nucleus that consumed less material would generate less energy, giving rise to fainter particle jets and fewer excited atoms. “The power source just went dim,” said Stephanie LaMassa, the study’s principal investigator.

LaMassa continued, “Because the life cycle of a quasar is one of the big unknowns, catching one as it changes, within a human lifetime, is amazing.” And since the life cycle of quasars is dependent on the life cycle of supermassive black holes, this discovery may help astronomers to explain how those that lie at the center of most galaxies evolve over time – including Sagittarius A*, the supermassive black hole at the center of our own Milky Way.

“Even though astronomers have been studying quasars for more than 50 years, it’s exciting that someone like me, who has studied black holes for almost a decade, can find something completely new,” added LaMassa.

The team’s research will be published in an upcoming issue of The Astrophysical Journal. A pre-print of the paper is available here.



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.

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“Super Saturn” Has an Enormous Ring System and Maybe Even Exomoons

“Super Saturn” Has an Enormous Ring System and Maybe Even Exomoons:

Illustration by artist Ron Miller of the gigantic ring system around J1407b. (© Ron Miller)


Illustration by artist Ron Miller of the gigantic ring system around J1407b. (© Ron Miller. Used with permission.)
Astronomers watching the repeated and drawn-out dimming of a relatively nearby Sun-like star have interpreted their observations to indicate an eclipse by a gigantic exoplanet’s complex ring system, similar to Saturn’s except much, much bigger. What’s more, apparent gaps and varying densities of the rings imply the presence of at least one large exomoon, and perhaps even more in the process of formation!

J1407 is a main-sequence orange dwarf star about 434 light-years away*. Over the course of 57 days in spring of 2007 J1407 underwent a “complex series of deep eclipses,” which an international team of astronomers asserts is the result of a ring system around the massive orbiting exoplanet J1407b.

“This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn’s rings are today,” said Eric Mamajek, professor of physics and astronomy at the University of Rochester in New York. “You could think of it as kind of a super Saturn.”

The observations were made through the SuperWASP program, which uses ground-based telescopes to watch for the faint dimming of stars due to transiting exoplanets.

The first study of the eclipses and the likely presence of the ring system was published in 2012, led by Mamajek. Further analysis by the team estimates the number of main ring structures to be 37, with a large and clearly-defined gap located at about 0.4 AU (61 million km/37.9 million miles) out from the “super Saturn” that may harbor a satellite nearly as large as Earth, with an orbital period of two years.

Watch an animation of the team’s analysis of the J1407/J1407b eclipse below:

The entire expanse of J1407b’s surprisingly dense rings stretches for 180 million km (112 million miles), and could contain an Earth’s worth of mass.

“If we could replace Saturn’s rings with the rings around J1407b,” said Matthew Kenworthy from Leiden Observatory in the Netherlands and lead author of the new study, “they would be easily visible at night and be many times larger than the full Moon.”

Saturn's relatively thin main rings are about 250,000 km (156,000 miles) in diameter. (Image: NASA/JPL-Caltech/SSI/J. Major)


Saturn’s relatively thin main rings are about 250,000 km (156,000 miles) in diameter. (Image: NASA/JPL-Caltech/SSI/J. Major)
These observations could be akin to a look back in time to see what Saturn and Jupiter were like as their own system of moons were first forming.

“The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites,” according to Mamajek. “However, until we discovered this object in 2012, no one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object.”

J1407b itself is estimated to contain 10-40 times the mass of Jupiter – technically, it might even be a brown dwarf.

Further observations will be required to observe another transit of J1407b and obtain more data on its rings and other physical characteristics as its orbit is about ten Earth-years long. (Luckily 2017 isn’t that far off!)

The team’s report has been accepted for publication in the Astrophysical Journal.

Source: University of Rochester. Image credit: Ron Miller.

Note: the originally published version of this article described J1407 at 116 light-years away. It’s actually 133 parsecs, which equates to about 434 light-years. Edited above. – JM



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!

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Is The Moon A Planet?

Is The Moon A Planet?:

Composite picture of a dark red Moon during a total lunar eclipse. Credit: NASA/ Johannes Schedler (Panther Observatory)


Composite picture of a dark red Moon during a total lunar eclipse. Credit: NASA/ Johannes Schedler (Panther Observatory)
What makes a planet a planet? The Moon is so big compared to the Earth — roughly one-quarter our planet’s size — that occasionally you will hear our system being referred to as a “double planet”. Is this correct?

And we all remember how quickly the definition of a planet changed in 2006 when more worlds similar to Pluto were discovered. So can the Moon stay the Moon, or is the definition subject to change?

Defining a planet

First, it’s important to understand what the official definition of a “planet” is, at least according to the International Astronomical Union. In its own words, according to a vote in Prague in 2006, the union has this definition:

“A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.”

What this means is that a planet must move around the Sun (and not move around something else), that it’s massive enough to have a round shape due to gravity, and that it will swoop up any dust or debris in its orbit as it moves around the Sun.

But let’s be clear on something; the IAU definition of planet is not without controversy. There is still a strong contingent of people who say that Pluto is indeed a planet, including the principal investigator of a spacecraft (New Horizons) to examine the world: Alan Stern.

“It’s an awful definition; it’s sloppy science and it would never pass peer review,” he told the BBC in 2006. He said that the line between dwarf planets and planets is too artificial, and that the definition of a “cleared neighborhood” is muddy. The Earth alone has many asteroids that follow it — or approach or cross its orbit — not to mention the massive planet Jupiter.

UV observations from Hubble show the size of water vapor plumes coming from Europa's south pole (NASA, ESA, and M. Kornmesser)


UV observations from Hubble show the size of water vapor plumes coming from Europa’s south pole (NASA, ESA, and M. Kornmesser)
Definition of a ‘satellite’

The Moon is not a unique phenomenon in our Solar System, in the sense that there are other planets that have satellites around them. Jupiter and Saturn have many dozens! Referring again to the IAU, the union also said in 2006 that it does not consider Charon a dwarf planet despite its large relative size to Pluto.

But Charon’s status as a moon could change in future, the IAU acknowledged. That’s primarily because the center of gravity in the system is not inside of Pluto, but in “free space between Pluto and Charon”. This center is called the “barycenter”, technically — and in Jupiter and Saturn’s cases, for example, all the barycenters of the various moons reside “inside” the huge gas giants.

Another caution, however: the IAU says “there has been no official recognition that the location of the barycenter is involved with the definition of a satellite.” So for now, it doesn’t have any bearing. That said, one question to consider is if the Moon’s barycenter is inside the Earth?

This Cassini raw image shows a portion of Saturn's rings along with several moons. How many can you find? Credit: NASA/JPL/Space Science Institute


This Cassini raw image shows a portion of Saturn’s rings along with several moons. How many can you find? Credit: NASA/JPL/Space Science Institute
The answer right now is “yes”. But over time, that barycenter will move outside of Earth. That’s because the Moon is slowly receding from our planet at a rate of about 3.8 centimeters (1.5 inches) a year. It’ll take a long time, but eventually the center of our system’s mass will not be within our planet.

And if you read back to an IAU interview in 2006, you’ll see that at that time, the IAU defined a “double planet” as a system where both bodies meet the definition of a planet, and the barycenter is not inside either one of the objects. So for now, the Earth is a planet and the Moon a satellite — at least under IAU rules.

We have written many articles about the Moon for Universe Today. Here’s an article about how long it takes to get to the Moon, and here are some interesting facts about the Moon. We’ve also recorded an entire episode of Astronomy Cast all about the Moon. Listen here, Episode 113: The Moon, Part 1.



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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Oldest Planetary System Discovered, Improving the Chances for Intelligent Life Everywhere

Oldest Planetary System Discovered, Improving the Chances for Intelligent Life Everywhere:

An artist rendition of Kepler-444 planetary system, which hosts five planets, all smaller than Earth. Credit: Tiago Campante, University of Birmingham, UK.


An artist rendition of Kepler-444 planetary system, which hosts five planets, all smaller than Earth. Credit: Tiago Campante, University of Birmingham, UK.
Using data from the Kepler space telescope, an international group of astronomers has discovered the oldest known planetary system in the galaxy – an 11 billion-year-old system of five rocky planets that are all smaller than Earth. The team says this discovery suggests that Earth-size planets have formed throughout most of the Universe’s 13.8-billion-year history, increasing the possibility for the existence of ancient life – and potentially advanced intelligent life — in our galaxy.

“The fact that rocky planets were already forming in the galaxy 11 billion years ago suggests that habitable Earth-like planets have probably been around for a very long time, much longer than the age of our Solar System,” said Dr. Travis Metcalfe, Senior Research Scientist Space Science Institute, who was part of the team that used the unique method of asteroseismology to determine the age of the star.


The star, named Kepler-444, is about 25 percent smaller than our Sun and is 117 light-years from Earth. The system of five known planets is very compact, and all five planets orbit the parent star in less than 10 days, or within 0:08 AU, roughly one-fifth the size of Mercury’s orbit.

“The star is slightly cooler than the Sun (around 5000 K at the surface, compared to 5800 K),” Metcalfe told Universe Today, “but the planets in this system are still expected to be highly irradiated and inhospitable to life,” with little to no atmospheres.

The team wrote in their paper that the system’s habitable zone lies 0:47 AU from the parent star and so all planets orbit well interior to the inner edge of Kepler-444’s ‘Goldilocks zone.’

The team was led by Tiago Campante, a research fellow at the University of Birmingham in the UK.

The planets were found by analyzing four years of Kepler data, as the spacecraft had nearly continuous observations of Kepler-444 during Kepler’s active mission. The space telescope took high-precision measurements of changes in brightness in stars in its field of view. There are tiny changes in brightness when planets pass in front of their stars.

Transit signals indicated five planets orbiting Kepler-444, although this star has a binary companion, an M-dwarf, and it was a tedious process to tease out all the data to determine what were planets and not other stars, as well as which star the planets were orbiting.

An image of the Kepler-444 star system using the NIRC2 near-infrared imager on the Keck II telescope. Credit: Tiago Campante et al.


An image of the Kepler-444 star system using the NIRC2 near-infrared imager on the Keck II telescope. Credit: Tiago Campante et al.
Metcalfe said the the job of “validating” the planets by ruling out all of the other possible “false positive” scenarios is always a big challenge for Kepler targets.

But asteroseismology was used to directly measure the precise age of the star. Asteroseismology, or stellar seismology is basically listening to a star by measuring sound waves. The sound waves travel into the star and bring information back up to the surface. The waves cause oscillations that Kepler observes as a rapid flickering of the star’s brightness.

How can this help determine a star’s age?

“As a star ages, it converts hydrogen into helium in the core,” Metcalfe said via email. “This changes the mean density of the star over time, and asteroseismology provides a very precise measure of the mean density (from the regular spacing of the individual oscillation frequencies).”

Metcalfe said that in this case, the uncertainty on the age of the star (and thus the planets, which formed essentially at the same time) is only 9%, compared to a typical uncertainty of 30-50% from other methods based on rotation (gyrochronology) or other properties of the star.

The team also noted in their paper that this finding may also help to pinpoint the beginning of the era of planet formation.

“I think this system has a lot to teach us about planet formation and the long-term evolution of planetary systems,” said Darin Ragozzine, a professor at Florida Institute of Technology and a a member of the discovery team, who specializes in multi-transiting systems. “With an age of 11.2 billion years, it means that this system formed near the beginning of the age of the Universe.”

The team wrote that this finding implies that small, Earth-size, planets may have readily formed at early epochs in the Universe’s history, even when metals were more scarce.

“By the time Earth formed, this star and its planetary system were already older than our planet is today,” Ragozzine told Universe Today. “We don’t know for sure if this system has stayed the same the whole time, but it is amazing to think that the little inner planet has gone around the star about a trillion times!”

To find out more about asteroseismology, check out a website called the Pale Blue Dot Project. Metcalfe launched a non-profit organization to help raise research funds for the Kepler Asteroseismic Science Consortium. The Pale Blue Dot Project allows people to adopt a star to support asteroseismology, since there is no NASA funding for asteroseismology.

“Much of the expertise for this exists in Europe and not in the US, so as a cost saving measure NASA outsourced this particular research for the Kepler mission,” said Metcalfe, “and NASA can’t fund researchers in other countries.”

Metcalfe added that the “adopt a star” program supported the asteroseismic analysis of Kepler-444, “determining the precise age that makes this ancient planetary system so interesting… This private funding from citizens around the world has been an invaluable resource to facilitate our research and fuel amazing discoveries like this one.”

You can help this research by adopting one of the Kepler stars or planetary systems.
This research was published today in the Astrophysical Journal.

The team’s paper is titled, “An Ancient Extrasolar System with Five Sub-Earth-Size Planets.”

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Luna vs. the Hyades! The 1st of 13 Occultations of Aldebaran Set For January 29th

Luna vs. the Hyades! The 1st of 13 Occultations of Aldebaran Set For January 29th:

Credit:


Getting closer… the Moon and Aldebaran from May 2014. Credit and copyright: Ziad El-Zaatari.
The cosmos is continually in motion.

Be it atoms, stars or snowflakes from the latest nor’easter pounding the New England seaboard, anything worth studying involves movement. And as skies and snowbound roads clear, this Wednesday and Thursday evening will give us a reason to brave the January cold, as the waxing gibbous Moon pierces the Hyades star cluster to graze past the bright star Aldebaran.

During Thursday night’s passage, the Moon will be 78% illuminated. In a sort ‘cosmos mimics controversy’ irony, the gibbous Moon is doing its best to mimic a sky bound ‘deflategate’ football just in time for Superbowl XLIX this weekend.

Stellarium


The motion of the Moon this week across the Hyades. Credit: Stellarium.
But the January 29th event also marks the first occultation of Aldebaran for 2015.

Fun fact: At magnitude +0.8, Aldebaran is the only star brighter than +1st magnitude north of the celestial equator that the Moon can currently occult. Regulus, the runner up, shines at magnitude +1.4.  Two other second magnitude stars — Antares and Spica — lie along the Moon’s path on occasion, and up until the 2nd century BC, it was possible for the Moon to occult Pollux in the constellation Gemini as well.

There are 13 occultations of Aldebaran in 2015, and the Moon occults the star 49 times overall until the last event in the current cycle on September 3rd, 2018. Aldebaran is also occulted by the Moon more often in the current 2010-2020 decade than any other bright star. You can even spy Aldebaran near the daytime Moon with binoculars, as we did back in 1996 from North Pole, Alaska.

Credit: Occult


Maps for the 13 occultations of Aldebaran  by the Moon in 2015, click to enlarge. solid lines denote regions were the occultation occurs under dark skies. Credit: Occult 4.0.
Of course, the January 29th event is an occultation only for the high Arctic, with only a scattering of villages and distant early warning stations along the northern Nunavut coast welcoming the sequence of 2015 occultations of the bright star.

The rest of us will see a close photogenic pass, as the Moon makes an end run through the Hyades star cluster every 27.3 day sidereal lunar month in 2015. The Moon will thus occult several members of the Hyades on each pass. Our best bet for North America is the occultation of Aldebaran on November 26th, though the Moon will be just 13 hours past Full.

68 Tauri. Credit: Occult 4.0


The occultation of 68 Tauri (a member of the Hyades) for January 29th. Credit: Occult 4.0.
Why doesn’t the path of the Moon just stay put with respect to the sky? Because the orbit of our Moon is fixed at an inclination of 5.1 degrees not with respect to our equator, but to the plane of the ecliptic. This means that the Moon’s orbit is in motion as well, and can wander anywhere from declination 28.6 degrees north to south as it cycles from a shallow to steep path every 18.6 years. We’re actually in a shallow year in 2015 (known as a minor lunar standstill) after which the apparent path of the Moon through the sky begins to widen again until April 2025.

An occultation is celestial motion that you can see in real time as a star or planet is photobomb’d by the onrushing Moon like a January snowplow… but those background stars are in motion as well.



The Hyades themselves — along with our own solar system — are moving around the galactic center. The nearest open cluster to us at 153 light years distant, the Hyades provided a unique object of study for 19th century astronomers. Astronomer Lewis Boss of the Dudley observatory spent several decades studying the proper motion — the apparent motion that a star seems to be moving across the sky from our solar system-bound perspective, measured in arc seconds — of the Hyades, and found the entire group was converging on a point in the constellation Orion near 6 hours 7’ right ascension and +7 degrees declination.

Starry Night


The imaginary convergent point of the Hyades in the night sky. Credit: Starry Night Education software.
Of course, this motion is relative and demonstrates a changing perspective, as the Hyades recedes from our solar system like a defensive line rushing to sack a quarterback.

OK, enough with the sports similes. The Hyades are so close that the actual Hyades Stream — often referred to as the Hyades Moving Group — is actually strewn across the constellations Orion, Taurus and Aries and more.

Some stars, such as 20 Arietis in the adjacent constellation Aries and Iota Horologii in the southern hemisphere may actually members as well. There’s always a bit of ongoing controversy when it comes to actual moving group membership, which is usually pegged by determining proper motion, coupled with the age and metallicity of prospective stars. Growing up in the Milky Way galaxy, our Sun was once a member of some unnamed ancient open cluster that has since long dispersed, like the Hyades are in the process of doing now.

Photo by author


The asterism of the Hyades and the ‘eye of the Bull.’ Photo by author.
The Hyades contains hundreds of stars and ironically, Aldebaran is not a member of the cluster, but is merely 65 light years away from us in the foreground. The V-shaped asterism of the Hyades gives the Head of Taurus the Bull its distinctive shape. The Hyades are named after the rain nymph daughters of Atlas from Greek mythology, whose half daughters the Pleiades also adorn the nearby sky.

And as an added bonus, don’t miss comet C/2014 Q2 Lovejoy crossing the constellation Triangulum, also nearby. Q2 Lovejoy reaches perihelion this week on January 30th, and although it’s completing with the evening Moon, it’s still holding out at a respectable magnitude +4.5.

Credit:


Comet Q2 Lovejoy skirts by  the Hyades and the Pleiades. Credit and Copyright: John Chumack.
All reasons to get out these chilly January evenings and ponder a hurried universe continually in motion, both fast and slow.

-Check out Q2 Lovejoy on January 30th courtesy of the Virtual Telescope project.



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.

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Dawn Captures Best Images Ever of “Hipster Planet” Ceres

Dawn Captures Best Images Ever of “Hipster Planet” Ceres:

Animation of Ceres made from images acquired by Dawn on Jan. 25, 2015. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)


Animation of Ceres made from images acquired by Dawn on Jan. 25, 2015. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)
This is the second animation from Dawn this year showing Ceres rotating, and at 43 pixels across the images are officially the best ever obtained!

NASA’s Dawn spacecraft is now on final approach to the 950 km (590 mile) dwarf planet Ceres, the largest world in the main asteroid belt and the biggest object in the inner Solar System that has yet to be explored closely. And, based on what one Dawn mission scientist has said, Ceres could very well be called the Solar System’s “hipster planet.”

“Ceres is a ‘planet’ that you’ve probably never heard of,” said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We’re excited to learn all about it with Dawn and share our discoveries with the world.”

Originally classified as a planet, Ceres was later categorized as an asteroid and then reclassified as a dwarf planet in 2006 (controversially along with far-flung Pluto.) Ceres was first observed in 1801 by astronomer Giuseppe Piazzi who named the object after the Roman goddess of agriculture, grain crops, fertility and motherly relationships. (Its orbit would later be calculated by German mathematician Carl Gauss.)

“You may not realize that the word ‘cereal’ comes from the name Ceres,” said Marc Rayman, mission director and chief engineer of the Dawn mission at JPL. “Perhaps you already connected with the dwarf planet at breakfast today.”

Ceres: part of this nutritionally-balanced Solar System!

Comparison of HST and Dawn FC images of Ceres taken nearly 11 years apart. Credit: NASA.


Comparison of HST and Dawn FC images of Ceres taken nearly 11 years apart. Credit: NASA.
The animation above was made from images taken by Dawn framing camera on January 25, 2015 from a distance of about 237,000 km (147,000 miles). These are now the highest-resolution views to date of the dwarf planet, 30% more detailed than those obtained by Hubble in January 2004.

And there’s that northern white spot again too… seen in observations from earlier this month and in the 2003-04 HST images, scientists still aren’t quite sure what it is. A crater wall? An exposed ice deposit? Something else entirely? We will soon find out.

“We are already seeing areas and details on Ceres popping out that had not been seen before. For instance, there are several dark features in the southern hemisphere that might be craters within a region that is darker overall,” said Carol Raymond, Dawn deputy principal investigator at JPL.

Full-frame image from Dawn of Ceres on approach, acquired Jan. 25, 2015. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)


Full-frame image from Dawn of Ceres on approach, acquired Jan. 25, 2015. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)
From now on, every observation of Ceres by Dawn will be the best we’ve ever seen! This new chapter of the spacecraft’s adventure has only just begun.

Dawn is scheduled to arrive at Ceres on March 6. Follow the progress of the Dawn mission here.

Source: NASA/JPL

*(Does this mean that Ceres has now gone “mainstream?” Hmm… oh well, it’s still cool.)



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!

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