Astronomy
esiegel | November 5, 2015"Studying whether there's life on Mars or studying how the universe began, there's something magical about pushing back the frontiers of knowledge. That's something that is almost part of being human, and I'm certain that will continue." -Sally Ride
If you came to the Solar System some 500 million years after its formation, you would've found two world with oceans of liquid water, continents and all the conditions we know of for life to begin thriving: Earth and Mars. But unlike our own world, Mars' organic history was cut short when it lost its atmosphere and became a barren, desert…
esiegel | November 5, 2015"Based on our understanding of how galaxy clusters grow from the very beginning of our universe, this cluster should be one of the five most massive in existence at that time." -Peter Eisenhardt
While deep galaxy surveys from telescopes like Hubble are great for identifying distant individual galaxies, they're not wide-field enough to find massive clusters. Similarly, wide-field surveys like SDSS don't go deep enough to find the most distant clusters.
Image credit: NASA/JPL-Caltech/UCLA, for the WISE mission.
But thanks to the all-sky infrared survey performed by NASA's WISE mission,…
esiegel | November 3, 2015"This scenario implies that the giant planet instability is not the source of the Late Heavy Bombardment and that terrestrial planet formation finished with the giant planets in their modern configuration." -Nathan A. Caib & John E. Chambers
It's a common but nonetheless spectacular occurrence when our leading scientific theories -- the ones with the best explanations for the observed phenomena -- run into conflict with what we see. Sometimes, it's the power of simulations that show us the way.
In 2005, scientists put forth the "Nice Model" to explain the configuration of the Solar…
esiegel | October 28, 2015“When you arise in the morning, think of what a precious privilege it is to be alive — to breathe, to think, to enjoy, to love.” -Marcus Aurelius
How old is life on Earth? If all you had to go on was the fossil record, you'd run into severe trouble once you went back more than one or two billion years, as all your rock would have metamorphosed, making examination and identification of fossils impossible. But recently, we've discovered another method: to measure the isotopic content of carbon deposits in ancient rock formations.
Image credit: E A Bell et al, Proc. Natl. Acad. Sci. USA, 2015,…
esiegel | October 26, 2015“No matter how ‘normal’ people look, living ‘ordinary’ lives, everyone has a story to tell. And may be, just like you, everyone else is a misfit too.” -Sanhita Baruah
Every century or so, possibly even more frequently, a supernova goes off somewhere in the Milky Way galaxy. While the explosion itself is only visible for a few months, the remnant sticks around for many thousands of years. Although it isn't always visible in the portion of the spectrum our eyes are sensitive to, X-rays, Ultraviolet light, infrared and radio observations bring them to life.
Image credit: NASA/JPL-Caltech, GALEX…
esiegel | October 21, 2015When we look at the vast expanse of stars in the night sky, we can't help but wonder what else is out there. Not just at the gas giants, rocky worlds, comets, asteroids, moons, and homeless planets strewn throughout our galaxy and all the galaxies beyond our own, but about what life -- what possibilities -- exist beyond our home world.
Illustration credit: NASA.
Very recently, a most unusual star -- KIC 8462852 -- had its light-curve data released by Kepler team, containing a series of unusually large, and inconsistent, drops in brightness around the star, fueling speculation that perhaps…
esiegel | October 20, 2015When you take a large amount of mass and put it all together in a small volume of space, you fully expect gravity to do its thing, and eventually collapse things down as far as they'll go. You can imagine that for compact masses with large distances between them -- like planets in the solar system or stars in the galaxy -- this will take a very long time: longer than the age of the Universe.
Image credit: NASA/ESA and A. Feild, of the known globular clusters around the Milky Way.
But what about globular clusters: hundreds of thousands of stars collected in a spherical region of space just…
esiegel | October 19, 2015“My Lord, the fleet has moved out of lightspeed. Com Scan has detected an energy field protecting an area of the sixth planet of the Hoth System. The field is strong enough to deflect any bombardment.” -General Veers, Star Wars: The Empire Strikes Back
Out beyond Saturn’s main rings lie a number of prominent moons: Titan, Dione, Rhea, and the subject of today’s post, Enceladus, the whitest, most reflective moon of all.
Image credit: NASA / Cassini-Huygens mission / Imaging Science Subsystem.
Unlike all the other moons in our Solar System, Enceladus’ most unique features is its active…
esiegel | October 16, 2015“In such moments, offering up his heart at the hour when the flowers of night inhale their perfume, lighted like a lamp in the center of the starry night, expanding his soul in ecstasy in the midst of the universal radiance of creation, he could not himself perhaps have told what was passing in his own mind; he felt something depart from him, and something descend upon him, mysterious interchanges of the depths of the soul with the depths of the universe.” -Victor Hugo
The night sky is a memorable, inimitable sight. With the exception of the planets, the stars that shine so brightly and…
esiegel | October 14, 2015“If I had to describe myself to an alien I’d say I was bigger than the average human, enjoy a drink or two with a good meal and have a bigger head than most. I’d also say I’m really handsome — especially if they were a female alien.” -Dwayne Johnson
The fact that Earth has not only life on it, but had the potential for life just from the raw ingredients that the Universe birthed us with should give us tremendous hope for the future. Not only might we find life like us around other stars on a planet not too different from our own, but our own backyard might offer some possibilities -- either…
esiegel | October 13, 2015“There is no kind of harassment that a man may not inflict on a woman with impunity in civilized societies.” -Denis Diderot
Last week, news broke that UC Berkeley astronomer Geoff Marcy -- perhaps the most famous single person in the field of exoplanet discoveries and study -- was found guilty by a University panel of sexually harassing at least four students over a period of 2001-2010, with allegations and further accusations extending far beyond that. I wish I could tell you it's a one-off, a rarity, or a thing that will end with the dismissal of Geoff Marcy from his position.
Image credit…
esiegel | October 12, 2015“If I want water, I’ll have to make it from scratch. Fortunately, I know the recipe: Take hydrogen. Add oxygen. Burn.” -Andy Weir
It wasn't merely one discovery that led to the announcement of liquid water on Mars, but a slew of pieces of evidence of a watery past, including dried-up riverbeds, sedimentary rock formations, martian spherules, frozen lakes and subsurface ice.
Image credit: NASA/JPL/Cornell/USGS, Mars Opportunity Rover.
Couple that with the recurring slope lineae -- and the discovery that they grow and leave salt deposits behind -- and you've got a planet with not only liquid…
esiegel | October 7, 2015We live in a Universe full of galaxies, supermassive black holes, and violence. The violence is particularly relevant here, because every so often, these galaxies merge, and if they each contain a supermassive black hole, the gravitational wave "ripples" that get sent through space will literally shake and affect everything that's in them.
Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech).
If you had a perfect clock --…
esiegel | October 5, 2015“The butterfly counts not months but moments, and has time enough.” -Rabindranath Tagore
When stars like the Sun reach the end of their lives, they all follow fairly predictable patterns:
Their cores contract, heat up, and start fusing helium into carbon.
Their outer layers expand into a luminous red giant.
When nuclear fusion ceases, they blow off their outer layers into a planetary nebula.
And the core contracts down to a hot, compact, degenerate and low-luminosity white dwarf.
Image credit: Robert Gendler, Jan-Erik Ovaldsen, Allan Hornstrup, IDA, via http://www.robgendlerastropics.com/…
esiegel | October 4, 2015“Suddenly, from behind the rim of the Moon, in long, slow-motion moments of immense majesty, there emerges a sparkling blue and white jewel, a light, delicate sky-blue sphere laced with slowly swirling veils of white, rising gradually like a small pearl in a thick sea of black mystery. It takes more than a moment to fully realize this is Earth . . . home.” -Edgar Mitchell, Apollo 14
It's arguable that we never came closer to leaving Earth than we did in the late 1960s and early 1970s, when the only humans in history ventured beyond low Earth orbit as part of the Apollo program. Have a listen…
esiegel | October 2, 2015“Birds sing after a storm; why shouldn’t people feel as free to delight in whatever sunlight remains to them?” -Rose Kennedy
It's a good thing that sunlight doesn't reach us simply from its moment of creation in the core of stars, otherwise we'd be bombarded with lethal gamma rays, rather than the life-giving UV, visible and infrared light we actually experience.
Image credit: Don Dixon of http://cosmographica.com/.
But that doesn't mean it isn't possible that the ultimate form of direct sunlight -- light from a nuclear reaction in the Sun -- to reach us, does it? Today's Ask Ethan focuses…
esiegel | October 1, 2015“The reports of the eclipse parties not only described the scientific observations in great detail, but also the travels and experiences, and were sometimes marked by a piquancy not common in official documents.” -Simon Newcomb
By far, one of the highlights of astronomy this year took place earlier this week: a total lunar eclipse featuring a perigee Moon. The sight of watching the Earth's shadow consume the Moon, eventually swallowing it whole and revealing a faint, red lunar disk, and then the process reversing itself, is unlike any other visible to the naked eye.
Image credit: Jose…
esiegel | September 29, 2015When young galaxies are first formed, they're accompanied by tremendous bursts of star formation, giving rise to billions of new stars within just a few million years. Yet how these galaxies first form in the initial stages is very much an open question. In addition, pretty much every large galaxy we find -- even in the extremely young Universe -- has a supermassive black hole at its center.
Image credit: NASA and The Hubble Heritage Team (STScI/AURA).
Is it conceivable that these black holes are the engines of newly formed galaxies? Is it even possible that these black holes preceded the…
esiegel | September 28, 2015“Bringing an asteroid back to Earth? What’s that have to do with space exploration? If we were moving outward from there, and an asteroid is a good stopping point, then fine. But now it’s turned into a whole planetary defense exercise at the cost of our outward exploration.” -Buzz Aldrin
What causes those mysterious bright spots on the Solar System's largest asteroid? Although those bright, highly-reflective features at the bottom of Occator crater on Ceres were what first jumped out at us, subsequent imaging has revealed that these features are present in many other (but not all!) locations…
esiegel | September 21, 2015“From our home on the Earth, we look out into the distances are strive to imagine the sort of world into which we are born.. But with increasing distance our knowledge fades, and fades rapidly, until at the last dim horizon we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be suppressed.” -Edwin Hubble
The deeper we look out into the Universe, the farther back in time we look. Our largest, deepest surveys have shown us not only galaxies in the very…