October 24, 2017

Review: Strange New Worlds by Ray Jayawardhana.


It’s weird to stop and think that we now live in a time that we know of the existence 573 new exoplanets, and by the time this cyber-ink goes to press, that rolling number will become obsolete. “In my day,” (my halcyon youth of the 70’s) Eight-tracks where still cool and astronomers guessed that exoplanets had to be common, but no one had as of yet found definitive evidence that this was indeed the case. [Read more...]

Review: Black Holes & Baby Universes by Stephen Hawking.

A Hawking Classic!

Many know the man, but few have read his work… this week, we take a look at Black Holes & Baby Universes, a collection of essays, speeches and musings by the eminent physicist Stephen Hawking. Though his body may be revenged by Lou Gehrig’s disease or ALS, his mind is as fertile as ever. [Read more...]

17.05.11: A “Cosmic Hand.”

Pulsar PSR B1509-58. (Credit: NASA/Chandra/CXC/SAO/P. Slane et al.)

“Wow…” Of course, this word often applies itself to the jaw-dropping field of astronomy… but the picture above really merits it. The image was snapped by the Chandra X-ray observatory. It displays pulsar PSR B1509-58 within a hand-shaped nebula located about 17,000 light years distant. [Read more...]

Review: What Are Gamma-ray Bursts? by Joshua S. Bloom.

Out from Princeton Press!

In 1888, astronomer Simon Newcomb made the now infamous quip that “we are probably nearing the limit of all we can know about astronomy…” One has to wonder what these 19th century scientists would make of the wonderful cosmological menagerie of black holes, energetic galactic nuclei, and the topic of today’s review. [Read more...]

05.05.11: Simulating Dark Matter.

The tadpole galaxy UGC 10214…being strung along by dark matter?

(Credit: Hubble/NASA/H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin).

How do you study the gravitational effects of dark matter on galaxy rotation over the span of a billion plus years? Simple; you get a supercomputer to do it for you! That’s exactly what 13-year old Cole Kendrick of Los Alamos MiddleSchool did to win the 21st New Mexico Supercomputing Challenge hosted recently by Los Alamos National Laboratory in New Mexico. Using an initial Python code, he condensed what would amount to 1 billion years of rotation into a period of 15 days… [Read more...]

14.04.11: Antares: A Deep Sea Neutrino Detector.

Depiction of Antares along with a photo closeup of one of the optical detectors. 

(Credit: F.Montanet, CNRS/IN2P3 and UJF for Antares)

   A unique astrophysical observatory has taken shape on the ocean floor of the Mediterranean. ANTARES, or the Astronomy with a Neutrino Telescope and Abyss environmental RESearch project, has been fully operational since May 2008 and is in the business of detecting Cherenkov radiation flashes caused by interactions of high energy muon neutrinos with the water in the deep Mediterranean Sea. [Read more...]

Review: Gravity’s Ghost by Harry Collins.

Out from Chicago Press!

Think your latest scientific quest is an impossible challenge? Let me introduce you to the team at the twin Laser Interferometry Gravitational wave Observatories (LIGO) and show you what they face. This week’s review installment is Gravity’s Ghost: Scientific Discovery in the Twenty-first Century by Harry Collins and out from Chicago University Press. [Read more...]

07.04.11: Catching a Black Hole in the Act.

An artist’s conception of a black hole gobbling a star. (Credit: NASA/CXC/M. Weiss).

NASA’s swift spacecraft caught something interesting on the night of March 28th, 2011. Launched in 2004, the spacecraft is designed to detect extragalactic x-ray and gamma-ray flashes. And what a flash they caught in GRB 110328A; a burst four billion light years distant that peaked at a brightness one trillion times that of our own Sun. But what’s truly interesting was that the power curve seen by astronomers was consistent with a galactic mass black hole devouring a star. Word on the astro-street from the Bad Astronomer, Phil Plait is that a yet to be released set of Hubble follow up images of the region seem consistent with the burst occurring near the core of a distant galaxy. In addition, NASA’s Fermi satellite, which also watches for gamma-ray bursts, has detected no past activity from the galaxy in question; this was an individual event without precedent. Did astronomers witness a “death by black hole” of a star? Perhaps such an event could occur if a nearby passage of another star put the body on a doomsday orbit. And interesting side note; astronomers established a thread to track GRBs in another pair of science/astronomy blogs that you might have heard of, the Bad Astronomy/Universe Today bulletin board. Much of the initial discovery and follow-up action occurred here, a forum worth following. And they say, “What good is blogging…”

        

05.04.11: Student Tool Aids Astrophysicists.

  

Spectral Energy Distribution for Epsilon Aurigae. (Credit: NASA/JPL CalTech/D. Hoard).

We love it when we can put the words “students,” and “astrophysics discoveries” in the same sentence. Recently, students from San Mateo and Hillsdale High School in partnership with NASA and San Mateo College unveiled a new educational tool for budding astrophysicists. [Read more...]

16.03.11: The LIGO/Virgo Collaboration Passes “The Envelope.”

On the hunt for Gravitational Waves in the heart of Louisiana… (Photo by Author).

Amidst a week of killer-moons and earthquake paranoia, a real science story with potentially big implications was shaping up in Arcadia, California.  On March 14th, the LIGO (Laser Interferometer Gravitational Wave Observatory) and European-based Virgo scientists gathered to “pass the envelop” (their spelling!) On a hoped-for first detection of a gravitational wave. [Read more...]

19.02.11: V1647 Orionis-A Request for Observations.

This past Tuesday, a call for observations went out from the American Association for Variable Star Observers (AAVSO) for observations past and present of a very poorly understood variable. In AAVSO Special Notice #235 Dr. Colin Aspin of the University of Hawaii has requested images past and present of the area surrounding M78 and the object known as McNeil’s Nebula.

[Read more...]

AstroEvent: When will Epsilon Aurigae Brighten?

One of the strangest variable stars is worth watching this spring.  Back in 2009, we alerted viewers to monitor the curious variable Epsilon Aurigae. Once every 27.06 years, this star dips nearly a magnitude in brightness down to about +3.8, markedly discernable to the naked eye. This drop lasts for over a year before Epsilon Aurigae returns to its former self. This spring should witness such an occurrence.

[Read more...]

13.02.11: A Monster in M87.

NASA’s Chandra X-Ray observatory recently peered into the heart of the M87 galaxy in the constellation Virgo. Well known to backyard observers as one of the highlights of the Virgo galaxy cluster, M87 harbors something truly spectacular; one of the most massive black holes known. In fact, researchers American Astronomical Society meeting in Seattle Washington earlier last month upgraded to WOW factor of the M87, calculating a mass of 6.6 billion suns.

[Read more...]

04.02.11: A Gravitational Lensing Exoplanet.

Artist’s rendition of the gravitational lens technique MOA uses to spot exoplanets…(All Images coutesy of the MOA Consortium: Used with Permision).

Amid the sexier transiting exoplanet discoveries released earlier this week by the NASA Kepler team came an exoplanet discovered by a lesser known technique; that of gravitational lensing. MOA, or Microlensing Observations for Astrophysics, is a joint Japan/New Zealand venture looking for dark matter objects passing in front of stars and bending their light via gravitational lensing. First predicted by Einstein and famously observed during the total solar eclipse of 1919, several gravitational lenses are now known and documented in nature, from stellar type objects to massive galaxy clusters. [Read more...]

Death by…Gamma-Ray Burst!


An artist’s impression of a very bad day…(Credit: ESO/A. Roquette).

Sure, we’ve all seen the movies with the impending death by asteroid or comet. You might have even heard of the havoc that can be wrecked by the Sun or an errant black hole, but have you ever heard of death by… gamma ray burst? Very much outside of public consciousness, this was but one of the more exotic ways humanity could have an official bad day that was outlined in Phil Plait’s outstanding Death from the Skies! But what are these exotic beasties, and just how likely are they? [Read more...]

01.06.10: Do Primordial Magnetic Fields Roam the Cosmos?

An artist's conception of a blazar. (Credit: NASA/Goddard Space Flight Center).

An artist's conception of a blazar. (Credit: NASA/Goddard Space Flight Center).

 

   NASA’s Fermi Gamma-ray Space Telescope may have uncovered a new high energy mystery. Like our own Earth, galaxies and even large scale galaxy clusters have magnetic fields shrouding them. The fields of mature galaxies such as our own Milky Way should have been seeded during the early formation of their weaker ancient counterparts. Perhaps these got their start from early supernovae, which spewed charged particles forth into the cosmos. These galactic magnetic fields may even help control the modern era rates of star formation, as well as regulate interstellar gas and guide cosmic rays. [Read more...]

23.05.10-Are Black Holes the Key to Dark Matter?

Artist's impression of a torus surrounding a massive black hole. (Credit V. Beckmann.NASA).

An artist’s conception of a gas torus surrounding a super-massive black hole. (Credit: V.Beckmann/NASA).

   For the past few decades, astronomers have been hot on the trail of the “missing” part of our universe. About 23 percent of our universe appears to be comprised of dark matter, non-luminous material that gives itself away only via gravitational interaction. Pinning down dark matter has been the name of the cosmological game, and researchers have looked at everything from MACHOs (Massive Compact Halo Objects) to WIMPs (Weakly Interacting Massive Particles) to everything conceivable, however bizarre or mundane, in between. Now, researchers at the National Autonomous University of Mexico may have gained a key insight into the nature of dark matter, as well as the evolution of galaxies and how the super-massive black holes at their heart are formed. Researchers William Lee and Xavier Hernandez studied the absorption rates of these massive beasts, noting how simulations stacked up with what we observe in the universe we see today. Their findings suggest that dark matter at the cores of galaxies should be fairly homogonous; at a critical mass larger than seven solar masses per cubic light year, a runaway effect occurs, twisting and altering galaxies from the stately whirlpool we see today. Of course, with this mass limit constraint, one could easily ask the question; how did these black holes reach multi-million solar mass status in the first place?  Further studies and data gathered by platforms such as the James Webb Space Telescope will no doubt shed “new light” (bad pun intended) on dark matter as well as tweak standard models and refine the nature of its role in the evolution of the cosmos.

12.05.10- White Dwarf Lite?

 

A comparison of Kepler's latest planetary finds. (Graphic Credit: NASA).

A comparison of Kepler's latest planetary finds. (Graphic Credit: NASA).

 

   The Kepler space telescope may have bagged an unexpected prize during its hunt for exo-planets. Along with five published exoplanets illustrated above, Kepler snared two potentially bizarre objects. Dubbed KOI (Kepler Objects of Interest) -81 and 74, these companions actually appear dimmer passing behind the parent star rather than in front of it. This suggests a bright luminous object(s) with an Earth-like diameter but much more massive… a white dwarf? Possibly, but the objects seem to be physically too large to fit this class of objects. White dwarfs have an upper limit of about 1.4 solar masses, also known famously as the Chandrasekhar limit. Recently, scientist Jason Rowe of NASA Ames research center has been able to directly measure the masses of these companions by measuring the way the companions physically warp, or distort the bodies of their primary companions. The result; these stars are in the realm of 0.1 solar masses, which would make them some the lightest white dwarfs known. Obviously, this also becomes a problem because although small and luminous, KOI-81 and -74 probably aren’t supported solely by electron degeneracy pressure that characterizes standard classical white dwarfs. The situation just got stranger and stranger… were these objects large super-heated planets or light white dwarfs?

Enter an international team of astronomers meeting at Kavli Institute in Peking (Beijing) China. Using an innovative technique known as Doppler boosting, they were able to pinpoint the mystery objects mass at 0.2 solar masses, on the low end but still in the realm of a white dwarf. This makes even more sense if one considers a white dwarf accreting mass from a primary companion, ala a Type 1A supernovae candidate…(hey, didn’t we write in this space last week about the lack of these beasties?)   Doppler boosting works in terms of catching subtle fluctuations in the brightening of an approaching object as measured by photons received over a given unit of time and dimming as it recedes…altogether a complicated affair, considering this must be untangled from a flurry of other signals. This unexpected find illustrates that surreptitious discoveries are often the norm in astronomy, if only someone is willing to look for them!