Astronomy Archives

December 22, 2014December 23, 2015 by Shannon Hall

Why Care About Astronomy?

Babak Tafreshi (TWAN), ESO Ultra HD Expedition

I need to get something off my chest. A month or so ago I was sitting in a classroom surrounded by 10 peers. For the first time this semester we had the opportunity to spend the entire day discussing astronomy. And I was thrilled to dive into that brilliant subject, which I have adored for most of my 26 years.

But it didn’t take long before the day turned sour. Most of my classmates touched on one common theme: why should we care about astronomy when it has no practical applications? It’s a concern I have seen time and time again from students, museum guests, and readers alike.

So dear world, here is why you should care.

It’s true that astronomy has few practical applications and yet somehow its advances benefit millions of people across the world.

Just as astronomy struggles to see increasingly faint objects, medicine struggles to see things obscured within the human body. So astronomy has developed technology used in CAT scanners and MRIs. It has also developed technology now used by FedEx to track packages, GPS satellites to determine your location, apple to develop a camera for your iPhone, to name a few.

But all of these are mere second thoughts, benefits that have occurred without the primary intention of the maker. And that is what makes astronomy beautiful. To study something — not because we’re looking to gain anything in particular, but out of sheer curiosity — is what makes us human.

Doing things for their own sake creates room for mindfulness and joy. Aristotle makes this point in his Nicomachean Ethics. He says: “the work is the maker in actuality; so he loves his work, because he loves his existence too. And this is a fact of nature; for what he is in potentiality, the work shows in actuality.”

Work itself is inherently valuable and it is somehow connected to our very existence. It stands alone and not as a path toward a paycheck or a practical application. Countless studies show just this. In one famous example, psychologists Edward Deci and Richard Ryan, both from the University of Rochester, asked two groups of college students to work on various puzzles. One group was paid for each puzzle it solved. The other group wasn’t.

Deci and Ryan found that the group that was paid to solve puzzles quit the second the experiment was over. The other group, however, found the puzzles intrinsically fascinating, and continued to solve the puzzles well after finishing the experiment. The second group found joy in the puzzles even when — and perhaps because — there was no monetary value to gain. There’s mindfulness in the act of work itself.

Then there is the sheer joy of looking up. On the darkest of nights, far from the city lights, thousands of stars are sprinkled from horizon to horizon. We now know there are over one billion stars in our galaxy and over one billion galaxies in our universe. It fills me with such wonder and humility to know our small place in the vast cosmos above us.

I firmly believe that astronomy has a spiritual dimension, maybe not in the sense of a supreme being, but in the sense of how it connects us with something bigger than ourselves. It brings us closer to nature by illuminating the ongoing mysteries in the universe.

Because of astronomy we now know that the Universe sparked into existence 13.7 billion years ago. We’ve spotted shining pinpricks of light in the early universe and know them to be supermassive black holes, with such strong gravitational fields, that matter is raining down onto them. We’ve seen distant galaxies colliding in a swirl of stars, gas and dust. And we’ve spotted thousands of planets orbiting other stars.

We’ve glimpsed the wonders of the universe — both big and small — for others to appreciate. So while astronomy doesn’t set out with the intention of changing our lives on a practical level, it does change our lives. It has explained mysteries that have confounded us for thousands of years, but more crucially, it has opened up more mysteries than any of us can study in our lifetime.

I have to wonder: what human being isn’t compelled to study a discipline that sparks such curiosity and joy?

December 22, 2014December 23, 2015 by Vanessa Janek

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.

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

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. 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.”

December 18, 2014December 23, 2015 by Bob King

Holiday Lights So Bright You Can See ’em from Space

Christmas lighting displays like this one near Duluth, Minn. U.S. are visible from outer space. Credit: Bob King

Call it holiday light creep. A NASA satellite has been tracking the spread of Christmas lighting from 512 miles up for the past three years and according to the data, nighttime lights around many major U.S. cities shine 20 to 50 percent brighter during Christmas and New Year’s when compared to light output during the rest of the year. Not surprisingly, most it comes from suburban areas.

Christmas isn’t the only time holiday festivities spill into the cosmic night. In some Middle Eastern Cities nighttime lights shine more than 50 percent brighter during Ramadan than the rest of the year. Because snow reflects so much light, the researchers could only analyze snow-free cities lest they risk comparing apples to oranges. The team focused on the U.S. West Coast from San Francisco to Los Angeles and on cities south of a rough line from St. Louis to Washington, D.C.

The map compares the nighttime light signals from December 2012 and 2013 to the average light output for the rest of 2012 to 2014 in and around several large cities in Texas. Dark green shadings indicates increased lighting in December, primarily from outdoor holiday lights. Credit: NASA’s Earth Observatory/Jesse Allen

As someone who has spent many winter nights observing I can attest to snow being a major factor in nighttime sky brightness. Even downward shielded lighting must necessarily reflect upward and into the heavens when it strikes the snow below. Summer is a far darker time of year than winter across much of the northern U.S.

Close-ups of three cities using the Suomi-NPP satellite. Credit: NASA/ — Close-ups of three cities using the Suomi-NPP satellite data. Dark green pixels are areas where the lights are 50 percent brighter. Credit: NASA’s Earth Observatory/Jesse Allen

The orbital images were all taken by the Suomi NPP satellite, a joint NASA/National Oceanic and Atmospheric Administration mission, carries an instrument called the Visible Infrared Imaging Radiometer Suite (VIIRS) that detects light in a range of wavelengths from green to near-infrared as it flies over at roughly 1:30 a.m. and 1:30 p.m. each day. VIIRS has a low-light sensor that can distinguish night lights tens to hundreds of times better than previous satellites. In the U.S. the lights starting getting brighter the day after Thanksgiving and continued through News Year’s Day. Miguel Román, a scientist at NASA’s Goddard Space Flight Center and member of the Suomi NPP Land Discipline Team, made the discovery while researching urban energy use patterns in the context of greenhouse emissions. And you thought all those twinkly bulbs were just for fun.

NASA Sees Holiday Lights from Space

The science team found that light intensity increased by 30 to 50 percent in the suburbs and outskirts of major cities. Lights in the central urban areas didn’t increase as much as in the suburbs, but still brightened by 20 to 30 percent. This makes sense when you consider that folks in the ‘burbs not only decorate their homes but often extend Christmas displays across the yard and up into the trees.

In several cities in the Middle East, city lights brighten during the Muslim holy month of Ramadan, as seen using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where the lights are 50 percent brighter, or more, during Ramadan. Image Credit: NASA's Earth Observatory/Jesse Allen — In several cities in the Middle East, city lights brighten during the Muslim holy month of Ramadan, as seen using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where the lights are 50 percent brighter, or more, during Ramadan. Credit: NASA’s Earth Observatory/Jesse Allen

Holiday lighting – a simple joy of the season. Yet it reflects both the hopes and wishes of human culture and the mundane facts of energy use. Through satellites, we can step back and watch the world change in ways never thought possible. We truly live in the Age of the Anthopocene, a newly designated era reflecting the profound effect our species has had and continues to have on the planet. To see all the holiday space photos, check out Goddard’s Flickr page.

An overhead view of the Eastern U.S. Click for a Flick page showing all U.S. cities in the survey. Credit: NASA’s Earth Observatory / Jesse Allen

December 18, 2014December 23, 2015 by Elizabeth Howell

Kepler ‘K2’ Finds First Exoplanet, A ‘Super-Earth’, While Surfing Sun’s Pressure Wave For Control

Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech

It’s alive! NASA’s Kepler space telescope had to stop planet-hunting during Earth’s northern-hemisphere summer 2013 when a second of its four pointing devices (reaction wheels) failed. But using a new technique that takes advantage of the solar wind, Kepler has found its first exoplanet since the K2 mission was publicly proposed in November 2013.

And despite a loss of pointing precision, Kepler’s find was a smaller planet — a super-Earth! It’s likely a water world or a rocky core shrouded in a thick, Neptune-like atmosphere. Called HIP 116454b, it’s 2.5 times the size of Earth and a whopping 12 times the mass. It circles its dwarf star quickly, every 9.1 days, and is about 180 light-years from Earth.

“Like a phoenix rising from the ashes, Kepler has been reborn and is continuing to make discoveries. Even better, the planet it found is ripe for follow-up studies,” stated lead author Andrew Vanderburg of the Harvard-Smithsonian Center for Astrophysics.

Kepler ferrets out exoplanets from their parent stars while watching for transits — when a world passes across the face of its parent sun. This is easiest to find on huge planets that are orbiting dim stars, such as red dwarfs. The smaller the planet and/or brighter the star, the more difficult it is to view the tiny shadow.

Infographic showing how the Kepler space telescope continued searching for planets despite two busted reaction wheels. Credit: NASA Ames/W Stenzel

The telescope needs at least three reaction wheels to point consistently in space, which it did for four years, gazing at the Cygnus constellation. (And there’s still a lot of data to come from that mission, including the follow-up to a bonanza where Kepler detected hundreds of new exoplanets using a new technique for multiple-planet systems.)

But now, Kepler needs an extra hand to do so. Without a mechanic handy to send out to telescope’s orbit around the Sun, scientists decided instead to use sunlight pressure as a sort of “virtual” reaction wheel. The K2 mission underwent several tests and was approved budgetarily in May, through 2016.

The drawback is Kepler needs to change positions every 83 days since the Sun eventually gets in the telescope’s viewfinder; also, there are losses in precision compared to the original mission. The benefit is it can also observe objects such as supernovae and star clusters.

Kepler-62f, an exoplanet that is about 40% larger than Earth. It's located about 1,200 light-years from our solar system in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech — Kepler-62f, an exoplanet that is about 40% larger than Earth. It’s located about 1,200 light-years from our solar system in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech

“Due to Kepler’s reduced pointing capabilities, extracting useful data requires sophisticated computer analysis,” CFA added in a statement. “Vanderburg and his colleagues developed specialized software to correct for spacecraft movements, achieving about half the photometric precision of the original Kepler mission.”

That said, the first nine-day test with K2 yielded one planetary transit that was confirmed with measurements of the star’s “wobble” as the planet tugged on it, using the HARPS-North spectrograph on the Telescopio Nazionale Galileo in the Canary Islands. A small Canadian satellite called MOST (Microvariability and Oscillations of STars) also found transits, albeit weakly.

A paper based on the research will appear in the Astrophysical Journal.

December 18, 2014December 23, 2015 by Bob King

Comet Finlay in Bright Outburst, Visible in Small Telescopes

Comet Finlay on December 16th showing a bright coma and short tail. Credit: FRAM team

Short-period comet 15P/Finlay, which had been plunking along at a dim magnitude +11, has suddenly brightened in the past couple days to +8.7, bright enough to see in 10×50 or larger binoculars. Czech comet observer Jakub Cerny and his team photographed the comet on December 16th and discovered the sudden surge. Wonderful news!

While comets generally brighten as they approach the Sun and fade as they depart, any one of them can undergo a sudden outburst in brightness. You can find Finlay right now low in the southwestern sky at nightfall near the planet Mars. While outbursts are common, astronomers still aren’t certain what causes them. It’s thought that sub-surface ices, warmed by the comet’s approach to the Sun, expand until the pressure becomes so great they shatter the ice above, sending large fragments flying and exposing fresh new ice. Sunlight gets to work vaporizing both the newly exposed vents and aerial shrapnel. Large quantities of dust trapped in the ice are released and glow brightly in the Sun’s light, causing the comet to quickly brighten.

Some comets flare up dramatically. Take 29P/Schwassmann-Wachmann. Normally a dim bulb at 17th magnitude, once or twice a year it flares to magnitude 12 and occasionally 10!

Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt — Animated movie showing the expansion of the coma of Comet Holmes over 9 nights during its spectacular outburst in November 2007. Credit: 3.6-meter Canada-France-Hawaii telescope on Mauna Kea / David Jewitt

Whatever the reason, outbursts can last from days to weeks. It’s anybody’s guess how long 15P/Finlay will remain a relatively easy target for comet hungry skywatchers. While not high in the sky, especially from the northern U.S., it can be seen during early evening hours if you plan well.

By pure good chance, Comet Finlay will track with Mars through December into early January. They'll make a remarkably close pair on the evening of December 23rd. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print. Source: Chris Marriott's SkyMap software — By good luck, Comet Finlay will track with Mars through December into early January. On December 23rd, they’ll come together in a remarkably close conjunction. This map shows the nightly position of the comet from Dec. 18th through Jan. 12th. Mars’ location is shown every 5 nights. Positions plotted for 6:15 p.m. (CST) 1 hour and 45 minutes after sunset. Stars shown to magnitude 8. Star magnitudes are underlined. Click to enlarge and print for outside use. Source: Chris Marriott’s SkyMap software

Comet Finlay was discovered by William Henry Finlay from South Africa on September 26, 1886. It reaches perihelion or closest approach to the Sun on December 27th and was expected to brighten to magnitude +10 when nearest Earth in mid-January at 130 million miles (209 million km). Various encounters with Jupiter since discovery have increased its original period of 4.3 years to the current 6.5 years and shrunk its perihelion distance from 101 million to 90 million miles.

Comet Finlay appears considerably fainter in this pre-outburst photo taken on December 14th. Credit: Alfons Diepvens

Looking at the map above it’s amazing how closely the comet’s path parallels that of Mars this month. Unlike Comet Siding Spring’s encounter with that planet last October, Finlay’s proximity is line of sight only. Still, it’s nice to have a fairly bright planet nearby to point the way to our target. Mars and Finlay’s paths intersect on December 23rd, when the duo will be in close conjunction only about 10? apart (1/3 the diameter of the Full Moon) for observers in the Americas. They’ll continue to remain almost as close on Christmas Eve. Along with Comet Q2 Lovejoy, this holiday season is turning out to be a joyous occasion for celestial fuzzballs!

To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15 degrees high in the southwestern sky. Source: Stellarium — To give you a little context to make finding Comet FInlay easier, use this wide-view map. A line from bright Vega in the western sky left through Altair will take you directly to Mars and the comet. This map shows the sky at nightfall tonight when the comet will be about 15° high in the southwestern sky. Source: Stellarium

December 17, 2014May 8, 2017 by Shannon Hall

The Universe’s Tour Guide

A number companies are deploying satellites this year to create space-based internet services. Credit: AMNH.

The hazy, white horizon lifts away slowly, giving way to the blue and green, cloud-swept marble we call home. I take in a deep breath, astonished by the Earth’s staggering beauty in stark contrast to the sprinkled backdrop.

People are still shuffling into the 429-seat Hayden Planetarium at the American Museum of Natural History, their shadows projected onto the arched ceiling. A voice resonates in the dome’s spacious cavity. Brian Abbott, the planetarium’s assistant director, is welcoming everyone to the show. It’s a “highlights tour,” he says, covering most of the known universe in one fell swoop.

As we leave Earth further behind, the satellites appear, swarming above our planet like bees around a hive. Soon the curved orbits of other planets become visible and we fly toward Mars.

In minutes we are hovering above Valles Marineris, a canyon so massive it would stretch from Manhattan to Los Angeles. The projectors display six-meter resolution data from the Mars Global Surveyor. We see the canyon ridges in such incredible, 3D detail it seems we could reach out and touch the tallest peaks with our fingers.

Abbott’s voice is slow and soothing. He speaks with authority, mindful of every inflection he makes and every word he uses. He carefully constructs his sentences, but also takes the time to crack a few jokes along the way. It’s just another day at the office, and yet it sounds like he’s having the time of his life.

Abbott in his office at AMNH. Credit: Shannon Hall

Abbott never dreamed of becoming an astronomer. In high school he was on a very different path, headed toward a career in art. Then, in 1985, Halley’s comet was scheduled to appear in the night sky. “For some reason I needed to find it,” he said. So, from his backyard outside Philadelphia, he learned how to pinpoint the constellations and spot distant objects, like galaxies, nebulae and star clusters. When the comet finally came, he was able to spot it, a tiny target in the vast sky. It was a revelation that pumped him full of adrenalin on that long, dark night.

Yet while Abbott left art as a career choice behind, he has been able to integrate art with astronomy, as his planetarium show demonstrates. “I admire the niche he has created for himself in the intersection between art, visualization and science,” said colleague Jana Grcevich, a postdoctoral researcher at AMNH.

Just before starting work at the museum in 1999, however, Abbott was an unhappy graduate student in the astronomy department at the University of Toledo. “Who can explain what gets you out of bed in the morning,” he said. “It just wasn’t what moved me.” Frustrated with his lot in life, he had plans to drive his car across the country, Jack Kerouac style. But first, he attended one last meeting: the American Astronomical Society’s annual conference in Chicago.

There, among all the job listings, he saw only one that wasn’t a research or a faculty position. The AMNH needed someone to create the world’s first interactive atlas of the Universe. So Abbott started sniffing around and coincidentally ran into the planetarium’s famed director, Neil DeGrasse Tyson, in the hallway of their hotel. Yet “Neil wasn’t Neil back then,” Abbott recalled. “He was somewhat known but he wasn’t mobbed with people.”

The duo started talking, and in two weeks Abbott found himself living in New York City with a new job. But he doesn’t regret it for a second. “I feel like I’m almost divorced from the night sky living here. I’m not able to just go out in my backyard and set up a telescope and see stuff. But we have this great dome. And I can go in there and see the entire Universe far better than I can see in the night sky.”

Now, Abbott spends his days visualizing large data sets. For the past 14 years, he has been creating a three-dimensional map of the Universe. He’s constantly updating the atlas with recent data hot off the world’s biggest telescopes and best satellites. And in the planetarium, he turns this abstract data into the planets, stars and galaxies that visitors flock to see. “What we want to do is focus on the scientific story of the universe,” said Abbott. “And we want that reflected in our dome.”

As the Hayden Planetarium’s popularity suggests, there’s a surprising public appetite for such strict scientific cartography. “There’s always at least one time in the show when the air comes out of the room,” said Abbott, referring to the moment when the audience takes a collective breath, in awe of the universe above them.

I can recall easily when that moment came for me. We had just left the Milky Way galaxy. Looking back on our home galaxy, the bright yellow core was surrounded by gorgeous blue spiral arms and sweeping dust lanes. Swarms of smaller galaxies began to appear. In minutes, we saw the Tully Catalogue, which covers an astonishing 30,000 galaxies in total.

The audience gasped in awe at the sheer number of galaxies in our local neighborhood. It’s impossible not to feel small at a moment like that.

But we were nowhere near the farthest reaches of the Universe yet. In moments, we saw the total number of galaxies ever recorded in the Sloan Digital Sky Survey. A chill ran down my spine. There were over one million galaxies projected onto the dome. Each one has over 100 billion stars. And each one of those likely has 5 or even ten planets. There are so many opportunities for life in our vast Universe.

We continued to zoom out, until we reached the edges of the 46.6 billion-light-year-wide observable Universe. In just over an hour, the tour had grossly violated the speed of light. “So that’s the Universe,” Abbott said. “Any questions?”

December 17, 2014December 23, 2015 by Tim Reyes

NASA’s Curiosity Rover detects Methane, Organics on Mars

After a 20 month trek across Mars and careful analysis of data, NASA scientists have announced two separate detection of organics - in the surface and the air of Mars. (Photo Credit: NASA/JPL, Illustration - T. Reyes)

On Tuesday, December 16, 2014, NASA scientists attending the American Geophysical Union Fall Meeting in San Francisco announced the detection of organic compounds on Mars. The announcement represents the discovery of the missing “ingredient” that is necessary for the existence – past or present – of life on Mars.

Indeed, the extraordinary claim required extraordinary evidence – the famous assertion of Dr. Carl Sagan. The scientists, members of the Mars Science Lab – Curiosity Rover – mission, worked over a period of 20 months to sample and analyze Martian atmospheric and surface samples to arrive at their conclusions. The announcement stems from two separate detections of organics: 1) ten-fold spikes in atmospheric Methane levels, and 2) drill samples from a rock called Cumberland which included complex organic compounds.

The Tunable Laser Spectrometer, one of the tools within the Sample Analysis at Mars (SAM) laboratory on NASA's Curiosity Mars rover. By measuring absorption of light at specific wavelengths, it measures concentrations of methane, carbon dioxide and water vapor in Mars' atmosphere. (Image Credit: NASA/JPL-Caltech) — The Tunable Laser Spectrometer, one of the tools within the Sample Analysis at Mars (SAM) laboratory on NASA’s Curiosity Mars rover. By measuring absorption of light at specific wavelengths, it measures concentrations of methane, carbon dioxide and water vapor in Mars’ atmosphere. (Image Credit: NASA/JPL-Caltech)

Methane, of the simplest organic compounds, was detected using the Sample Analysis at Mars instrument (SAM). This is one of two compact laboratory instruments embedded inside the compact car-sized rover, Curiosity. Very soon after landing on Mars, the scientists began to use SAM to periodically measure the chemical content of the Martian atmosphere. Over many samples, the level of Methane was very low, ~0.9 parts per billion. However, that suddenly changed and, as scientists stated in the press conference, it was a “wow” moment that took them aback. Brief daily spikes in Methane levels averaging 7 parts per billion were detected.

The detection of methane at Mars has been claimed for decades, but more recently, in 2003 and 2004, independent research teams using sensitive spectrometers on Earth detected methane in the atmosphere of Mars. One group led by Vladimir Krasnopolsky of Catholic University, and another led by Dr. Michael Mumma from NASA Goddard Space Flight Center, detected broad regional and temporal levels of Methane as high as 30 parts per billion. Those announcements met with considerable skepticism from the scientific community. And the first atmospheric measurements by Curiosity were negative. However, neither group backed down from their claims.

Regions where methane appears notably localized in Northern Summer (A, B1, B2), andtheir relationship to mineralogical and geo-morphological domains. (A.) Observations of methane near the Syrtis Major volcanic district. (B.) Geologic map of Greeley and Guest (41) superimposed on the topographic shaded-relief from MOLA (42). The most ancient terrain (Npld, Nple) is Noachian in age (~3.6 - 4.5 billion years old, when Mars was wet), and is overlain by volcanic deposits from Syrtis Major of Hesperian (Hs) age (~3.1 - 3.6 billion yrs old). (Credit: Mumma, et al., 2009, Figure 3) — Regions where methane appears notably localized in Northern Summer (A, B1, B2), and their relationship to mineralogical and geo-morphological domains. (A.) Observations of methane near the Syrtis Major volcanic district. (B.) Geologic map of Greeley and Guest (41) superimposed on the topographic shaded-relief from MOLA (42). The most ancient terrain (Npld, Nple) is Noachian in age (~3.6 – 4.5 billion years old, when Mars was wet), and is overlain by volcanic deposits from Syrtis Major of Hesperian (Hs) age (~3.1 – 3.6 billion yrs old). (Credit: Mumma, et al., 2009, Figure 3)

The sudden detection of ten-fold spikes in methane levels in Gale crater is not inconsistent with the earlier remote measurements from Earth. The high seasonal concentrations were in regions that do not include Gale Crater, and it remains possible that the Curiosity measurements are of a similar nature but due to some less active process than exists at the regions identified by Dr. Mumma’s team.

This graphic shows tenfold spiking in the abundance of methane in the Martian atmosphere surrounding NASA's Curiosity Mars rover, as detected by a series of measurements made with the Tunable Laser Spectrometer instrument in the rover's Sample Analysis at Mars laboratory suite. (Image Credit: NASA/JPL-Caltech) — This graphic shows tenfold spiking in the abundance of methane in the Martian atmosphere surrounding NASA’s Curiosity Mars rover, as detected by a series of measurements made with the Tunable Laser Spectrometer instrument in the rover’s Sample Analysis at Mars laboratory suite. (Image Credit: NASA/JPL-Caltech)

The NASA scientists at AGU led by MSL project scientist Dr. John Grotzinger emphasized that they do not yet know how the methane is being generated. The process could be biological or not. There are abiotic chemical processes that could produce methane. However, the MSL SAM detections were daily spikes and represent an active real on-going process on the red planet. This alone is a very exciting aspect of the detection.

The team presented slides to describe how methane could be generated. With the known low background levels of methane at ~ 1 part per billion, an external cosmic source, for example micro-meteoroids entering the atmosphere and releasing organics which is then reduced by sunlight to methane, could be ruled out. The methane source must be of local origin.

This image illustrates possible ways methane might be added to Mars' atmosphere (sources) and removed from the atmosphere (sinks). NASA's Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere, implying both types of activity occur on modern Mars. A longer caption discusses which are sources and which are sinks. (Image Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan) — This image illustrates possible ways methane might be added to Mars’ atmosphere (sources) and removed from the atmosphere (sinks). NASA’s Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere, implying both types of activity occur on modern Mars. A longer caption discusses which are sources and which are sinks. (Image Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan)

The scientists illustrated two means of production. In both instances, there is some daily – or at least periodic – activity that is releasing methane from the subsurface of Mars. The source could be biological which is accumulated in subsurface rocks then suddenly released. Or an abiotic chemistry, such as a reaction between the mineral olivine and water, could be the generator.

The subsurface storage mechanism of methane proposed and illustrated is called clathrate storage. Clathrate storage involves lattice compounds that can trap molecules such as methane which can subsequently be released by physical changes in the clathrate, such as solar heating or mechanical stresses. Through press Q&A, the NASA scientists stated that such clathrates could be preserved for millions and billions of years underground.

The second discovery of organics involved more complex compounds in surface materials. Also since arriving at Mars, Curiosity has utilized a drilling tool to probe the interiors of rocks. Grotzinger emphasized how material immediately at the surface of Mars has experienced the effects of radiation and the ubiquitous soil compound perchlorate reducing and destroying organics both now and over millions of years. The detection of no organics in loose and exposed surface material had not diminished NASA scientists’ hopes of detecting organics in the rocks of Mars.

Comparisons between the amount of an organic chemical named chlorobenzene detected in the "Cumberland" rock sample and amounts of it in samples from three other Martian surface targets analyzed by NASA's Curiosity Mars rover. (Image Credit: NASA/JPL-Caltech) — Comparisons between the amount of an organic chemical named chlorobenzene detected in the “Cumberland” rock sample and amounts of it in samples from three other Martian surface targets analyzed by NASA’s Curiosity Mars rover. (Image Credit: NASA/JPL-Caltech)

Drilling was performed on several selected rocks and it was finally a mud rock called Cumberland that revealed the presence of organic compounds more complex than simple methane. The scientists did emphasize that what exactly these organic compounds are remains a mystery because of the confounding presence of the active chemical perchlorate which can quickly breakdown organics to simpler forms.

Examples from the Sample Analysis at Mars (SAM) laboratory's detection of Martian organics in a sample of powder that the drill on NASA's Curiosity Mars rover collected from a rock target called "Cumberland." (Image Credit: NASA/JPL-Caltech) — Examples from the Sample Analysis at Mars (SAM) laboratory’s detection of Martian organics in a sample of powder that the drill on NASA’s Curiosity Mars rover collected from a rock target called “Cumberland.”
(Image Credit: NASA/JPL-Caltech)

The detection of organics in the mud rock Cumberland required the drilling tool and also the scoop on the multifaceted robotic arm to deliver the sample into the SAM laboratory for analysis. To detect methane, SAM has an intake valve to receive atmospheric samples.

Dr. Grotzinger described how Cumberland was chosen as a sample source. The rock is called a mud stone which has undergone a process called digenesis – the metamorphosis of sediment to rock. Grotzinger emphasized that fluids will move through such rock during digenesis and perchlorate can destroy organics in the process. Such might be the case for many metamorphic rocks on the Martian surface. The panel of scientists showed a comparison between rock samples measured by SAM. Two in particular – from the rock “John Klein” and the Cumberland rock — were compared. The former showed no organics as well as other rocks that were sampled; but Cumberland’s drill sample from its interior did reveal organics.

Illustration of some of the reasons why finding organic chemicals on Mars is challenging. Whatever organic chemicals may be produced on Mars or delivered to Mars face several possible modes of being transformed or destroyed. (Image Credit: NASA/JPL-Caltech)

The analysis of the work was painstaking – harking back to the Sagan statement. The importance of discovering organics on Mars could not be understated by the panel of scientists and Grotzinger called these two discoveries as the lasting legacy of the Mars Curiosity Rover. Furthermore, he stated that the discovery and analysis methods will go far to guide the choice of instruments and their use during the Mars 2020 rover mission.

The discovery of organics completes the necessary set of “ingredients” for past or present life on Mars: 1) an energy source, 2) water, and 3) organics. These are the basic requirements for the existence of life as we know it. The search for life on Mars is still just beginning and the new discoveries of organics is still not a clear sign that life existed or is present today. Nevertheless, Dr. Jim Green, introducing the panel of scientists, and Dr. Grotzinger both emphasized the magnitude of these discoveries and how they are tied into the objectives of the NASA Mars program — particularly now with the emphasis on sending humans to Mars. For the Mars Curiosity rover, the journey up the slopes of Mount Sharp continues and now with greater earnestness and a continued search for rocks similar to Cumberland.

References:

Curiosity detects methane spike on Mars

NASA Rover Finds Active, Ancient Organic Chemistry on Mars

Research Papers, AGU Press Conerence via Ustream

Strong Release of Methane on Mars in Northern Summer 2003

Non-Detection of Methane in the Mars Atmosphere by the Curiosity Rover

Detection of methane in the martian atmosphere: evidence for life?

December 17, 2014December 23, 2015 by David Dickinson

Astro-Challenge: Taming the Pup-Can You Glimpse Sirius B?

White dwarf and companion star resolved.

Astronomy is all about thinking big, both in time and space.

The Earth turns on its axis, the Moon passes through its phases, and the planets come into opposition and solar conjunction on a routine basis.

Of course, on the other end of the spectrum, there are some events which traverse such colossal spans of time that the mere mortal life span of measly homo sapiens such as ourselves can never expect to cover them. Many comets have periods measured in centuries, or thousands of years. The axis of the Earth wobbles like a top, completing one turn every 26,000 years in what’s known as the Precession of the Equinoxes. Our solar system completes one revolution about the galactic center every quarter billion years…

Feeling puny yet? Sure, astronomy is also about humility. But among these stupendous cycles, there are some astronomical events that you just might be able to live through. One such instance is the orbits of double stars. And as 2015 approaches, we challenge you to see of the most famous white dwarf of them all, as it reaches a favorable viewing position over the next few years: Sirius B.

Sirius A and B in x-rays courtesy of Chandra. Credit: NASA/SAO/CXC.

Sirius itself is easy to find, as it’s the brightest star in Earth’s sky shining at magnitude -1.42. In fact, you can spot Sirius in the daytime sky if you know exactly where to look.

But it is one of the ultimate in cosmic ironies that the most conspicuous of stars in our sky also hosts such an elusive companion. The discovery of Sirius B awaited the invention of optics capable of resolving it next to its dazzling host. Alvan Clark Jr. and Sr. first spied the enigmatic companion on January 31^st, 1862 while testing their newly constructed 18.5 inch refractor, which was the largest at the time. The discovery was soon verified from the Harvard College Observatory, adding Sirius A and B to the growing list of multiple stars.

A 19th century refractor similar to the one used to discover Sirius B. Photo by the author.

And what a strange companion it turned out to be. Today, we know that Sirius B is a white dwarf, the cooling dense ember of a main sequence star at the end of its life. We call the matter in such a star degenerate, not as a commentary on its moral stature, but the state the electrons and the closely packed nuclei within under extreme pressure. Our Sun will share the same ultimate fate as Sirius B, about six billion years from now.

The challenge, should you choose to accept it, is to spot Sirius B in the glare of its host. The contrast in brightness between the pair is daunting: shining at magnitude +11, the B companion is more than 63,000 times fainter than -1.46 magnitude Sirius A.

The changing position angle of Sirius B. Note that the graphic is inverted, with north at the bottom. Created by the author.

A feat of visual athletics, indeed. Still, Sirius B breaks 10” in separation from its primary in 2015, as it heads towards apastron — its most distant point from its primary, at just over 11” in separation — in 2019. Sirius B varies from 8.2 and 31.5 AUs from its primary. Sirius B is on a 50.1 year orbit, meaning the time to cross this one off of your life list is over the upcoming decade. Perhaps making an animation showing the motion of Sirius B from 2015-2025 would present a supreme challenge as well.

Sirius culminates at local midnight right around New Year’s Eve, shining at its highest to the south as the “ball drops” ushering in 2015. Of course, this is only a fortuitous circumstance that is possible in our current epoch, and precession and the proper motions of both Sirius and Sol will make this less so millennia hence.

Sirius crossing the meridian at local midnight on New Year’s Eve. Credit: Stellarium.

Newsflash: there’s a very special visual treat in the offing next week, as comet C/2014 Q2 Lovejoy is currently hovering around +6^th magnitude and passes 19 degrees south of Sirius on Christmas Day… more to come!

Magnification and good seeing are your friends in the hunt for Sirius B. Two factors describe the position of a secondary star in a binary pair: its position angle in degrees, and separation in arc seconds. When it comes to stars that are a tough split, I find its better to estimate the position angle first before looking it up. A close match can often confirm the observation. Does a friend see the same thing at the eyepiece? A good star to “warm up” on is the +6.8 magnitude companion to Rigel in the foot of Orion, with a separation of 9”.

Nudging Sirius just out of view might allow the B companion to become apparent. Another nifty star-spliting tool is what’s known as an occulting bar eyepiece. Making an occultation bar eyepiece is easy: we’ve used everything from a small strip of foil to a piece of guitar string (heavy E gauge works nicely) for the central bar. An occulting bar eyepiece is also handy for hunting down the moons of Mars near opposition.

Sirius B also works its way into cultural myths and lore, not the least of which are the curious tales of the Dogon people of Mali. At the outset, it seems that these ancient people have knowledge of a small dense hidden companion star to Sirius, knowledge that requires modern technology to reproduce. Carl Sagan noted, however, that cultural contamination may have resulted in the late 19^th century discovery of Sirius B making its way into the Dogon pantheon. The science of anthropology is rife with anecdotes that have been carefully fed to credulous anthropologists only to be reported later as fact, all in the name of a good story.

All amazing things to ponder as you begin your 2015 quest for Sirius B, a bashful but fascinating star.

– Read more on the curious case of the Dogon and Sirius B.

-Want more white dwarfs? Here’s a handy list of white dwarfs of backyard telescopes.

December 16, 2014December 23, 2015 by Shannon Hall

What’s Next for the Large Hadron Collider?

A section of the LHC. Image Credit: CERN

The world’s most powerful particle collider is waking up from a well-earned rest. After roughly two years of heavy maintenance, scientists have nearly doubled the power of the Large Hadron Collider (LHC) in preparation for its next run. Now, it’s being cooled to just 1.9 degrees above absolute zero.

“We have unfinished business with understanding the universe,” said Tara Shears from the University of Liverpool in a news release. Shears and other LHC physicists will work to better understand the Higgs Boson and hopefully unravel some of the secrets of supersymmetry and dark matter.

On February 11, 2013 the LHC shut down for roughly two years. The break, known as LS1 for “long stop one,” was needed to correct several flaws in the original design of the collider.

The LHC’s first run got off to a rough start in 2008. Shortly after it was fired up, a single electrical connection triggered an explosion, damaging an entire sector (one-eighth) of the accelerator. To protect the accelerator from further disaster, scientists decided to run it at half power until all 10,000 copper connections could be repaired.

So over the last two years, scientists have worked around the clock to rework every single connection in the accelerator.

Now that the step (along with many others) is complete, the collider will operate at almost double its previous power. This was tested early last week, when scientists powered up the magnets of one sector to the level needed to reach the high energy expected in its second run.

“The machine that’s now being started up is almost a new LHC,” said John Womersley, the Chief Executive Officer of the Science and Technology Facilities Council.

With such a powerful new tool, scientists will look for deviations from their initial detection of the Higgs boson, potentially revealing a deeper level of physics that goes well beyond the Standard Model of particle physics.

Many theorists have turned to supersymmetry — the idea that for every known fundamental particle there exists a “supersymmetric” partner particle. If true, the enhanced LHC could be powerful enough to create supersymmetric particles themselves or prove their existence in subtler ways.

“The higher energy and more frequent proton collisions in Run 2 will allow us to investigate the Higgs particle in much more detail,” said Victoria Martin from Edinburgh University. “Higher energy may also allow the mysterious “dark matter” observed in galaxies to be made and studied in the lab for the first time.”

It’s possible that the Higgs could interact with — or even decay into — dark matter particles. If the latter occurs, then the dark matter particles would fly out of the LHC without ever being detected. But their absence would be evident.

So stay turned because these issues might be resolved in the spring of 2015 when the particle accelerator roars back to life.

December 15, 2014December 23, 2015 by Shannon Hall

Pluto-like Objects Turn to Dust Around a Nearby Young Star

ALMA image of the dust surrounding the star HD 107146. Dust in the outer reaches of the disk is thicker than in the inner regions, suggesting that a swarm of Pluto-size planetesimals is causing smaller objects to smash together. The dark ring-like structure in the middle portion of the disk may be evidence of a gap where a planet is sweeping its orbit clear of dust. Credit: L. Ricci ALMA (NRAO/NAOJ/ESO); B. Saxton (NRAO/AUI/NSF)

A planetary system’s early days readily tell of turmoil. Giant planets are swept from distant birthplaces into sizzling orbits close to their host star. Others are blasted away from their star into the darkness of space. And smaller bodies, like asteroids and comets, are being traded around constantly.

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have seen the latter: swarms of Pluto-size objects turning to dust around a young star. And the image is remarkable.

“This system offers us the chance to study an intriguing time around a young, Sun-like star,” said coauthor Stuartt Corder and ALMA Deputy Director in a news release. “We are possibly looking back in time here, back to when the Sun was about 2 percent of its current age.”

The young star, HD 107146, is located roughly 90 light-years from Earth in the direction of the constellation Coma Berenices. Although the star itself is visible in any small telescope, ALMA can probe the star’s radically faint protoplanetary disk. This is the star’s dusty cocoon that coalesces into planets, comets and asteroids.

ALMA’s image revealed an unexpected bump in the number of millimeter-size dust grains far from the host star. This highly concentrated band spans roughly 30 to 150 astronomical units, the equivalent of Neptune’s orbit around the Sun to four times Pluto’s orbit.

So where is the extra dust coming from?

Typically, dust in the debris disk is simply left over material from the formation of planets. Early on, however, Pluto-size objects (otherwise known as planetesimals) will collide and blast themselves apart, also contributing to the dust. Certain models predict that this leads to a much higher concentration of dust in the most distant regions of the disk.

Although this is the case for HD 107146, “this is the opposite of what we see in younger primordial disks where the dust is denser near the star,” said lead author Luca Ricci from the Harvard-Smithsonian Center for Astrophysics. “It is possible that we caught this particular debris disk at a stage in which Pluto-size planetesimals are forming right now in the outer disk while other Pluto-size bodies have already formed closer to the star.”

Adding to this hypothesis is the fact that there’s a slight depression in the dust at 80 astronomical units, or twice Pluto’s average distance from the Sun. This could be a slight gap in the dust, where an Earth-size planet is sweeping the area clear of a debris disk.

If true, this would be the first observation of an Earth-size planet forming so far from its host star. But for now that’s a big if.

The results will be published in the Astrophysical Journal and are available online.