November 19, 2017

Review Magnificent Mistakes in Mathematics by Alfred S. Posamentier & Ingmar Lehmann

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We’ve all be there. Standing at the chalkboard, (remember chalkboards?) we’ve all forgotten to “carry the two,” or made the cardinal sin of mathematics by attempting to divide by zero. Hey, it happens to the best of us sometimes.

So it’s comforting to realize that the rock stars of mathematics are prone to slip up on occasion as well. Only in their case, their mistakes may be so monumental as to approach greatness.   [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...]

2010: The Year in Science

2010 has been a tumultuous year in space and astronomical science. We’ve seen the beginning of a huge transition for manned space flight, as well as a look ahead at what astronomers would wish for if they had their say. What follows are a baker’s dozen of the biggest, weirdest, and most controversial science articles that made our astro-radar in 2010;

[Read more...]

Review: Agora

Agora Movie Poster.

Agora Movie Poster.

 

This week, I thought I’d give a quick Astroguyz shout-out to a historical astronomy movie that recently graced our Netflix inbox. Agora tells the tale of the astronomer and mathematician Hypatia and the last days of the library of Alexandria. The movie quietly came and went earlier this year, but it tells a tale that’s as timely as ever. [Read more...]

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!

24.04.10-Our Existence: Justified.

(Credit: NASA/JPL).

(Credit: NASA/JPL).

 Earth: Safe & Sound?

   The formation of the Earth poses a key dilemma to planetary accretionary theory; namely, why are we here at all? Standard models would say that the Earth and other planets coalesced out of the proto-solar nebula to form. However, spiral density waves within the same nebula should have drawn down orbital energy to shorten the planets orbit, slowly drawing it in. Looking at other “hot Jupiter” systems, that’s just what we see; large gas giant worlds that formed further out, only to migrate inward into tight orbits… just how did we end up in our nice, neat orbit?

Now, computational astrophysicist Mordecai-Mark Mac Loc at the American Museum of Natural History may have the answer. Accounting for temperature and spin variability, resonance key holes can occur; planets like Earth may simply spiral inward and get hung up in these safe zones between dragging pressure waves. Of course, a majority of proto-planets don’t make the cut and simply spiral inward to a fiery end, but they’re not around for us to see today. One discovery that would perhaps give observational weight to this theory would be the discovery of exo-Earths also parked in nice neat orbits… the Kepler space telescope may pave the way for this discovery as it stares off into Cygnus. For now, thank computational mathematics that you’re here reading this, just as it says you should be!

Space Telescopes, Part I: Optical.

 
(Credit: NASA/ESA/S. Gallagher/J. English).
(Credit: NASA/ESA/S. Gallagher/J. English).
 

 Hickson Group 31 of galaxies as imaged by Hubble.

   This weeks’ expose will kick off our four part series on orbiting space telescopes. For starters, we’ll begin with the most familiar; the optical wavelength. True, we as humans are biased towards this narrow band of the spectrum; we love to see pretty pictures that we can relate to.  But beyond this, telescopes that operate in the visual wavelengths have no less than revolutionized astronomy, as well as laid promise for perhaps giving us images of exo-Earths in our lifetimes. What follows is a rapid fire list of what was, is, and what to look for up and coming in the realm of optical astronomy in space: [Read more...]

19.10.09: 32 New Exoplanets Revealed!

Anybody notice the exoplanet tally on our front page hop up to 402 this morning? That’s because the European Southern Observatory (ESO) revealed a stunning 32 (count em!) new exoplanets identified this morning at their conference at Porto, Portugal. The discoveries were thanks to HARPS, the High Accuracy Radial Velocity Planet Searcher, a sensitive spectrograph attached to the 3.6 meter telescope at La Silla. First installed in 2003, HARPS has thus far discovered 75 of the 400+ worlds now known, or nearly 25%! today’s haul represents the largest single day release. Any special firsts? Well, the grab bag of exo-worlds substantially increases the pool of “super-earths”, as well as three planets found orbiting metal deficient stars, something that may be cause for tweaking planetary formation theory a bit. HARPS is capable of measuring radial shifts as small as 2 miles per hour, an impressive feat. The gauntlet has now been thrown; will the Kepler space telescope rise to the challenge as it stares into Cygnus looking for exo-transits? Do we sense a “exoplanet-war” brewing on mountain tops and chat boards across the world? Stay tuned!

21.9.9 Will Kepler spot “exo-moons?”

Let the staring begin… the Kepler spacecraft has its shutters open and is now ready for business. Just out the gate, the results have been astounding. First, there was the discovery of HAT-P-7b, a transiting exo-planet that was spotted last month, complete with atmosphere. Now, calculations have shown that Kepler may be sensitive enough during the span of its four year mission to detect another first; exo-moons, or Earth-mass moons orbiting Saturn-mass planets. Kepler is in an Earth trailing orbit and sports a 0.95 meter 95 mega pixel (that’s an array of 42 2200×1024 pixel each CCDs!) aperture camera that will stare at the star-rich Cygnus-Lyra region looking for tiny dips in the apparent brightness of over a 100,000 stars. Expect the tally of new exo-planets to climb in the coming months!

 

September 2009:News & Notes.

Is Betelgeuse shrinking? Everyone’s favorite candidate for a nearby supernova has been exhibiting some alarming behavior as of late. The red giant star Betelgeuse, located in the shoulder of Orion, has decreased in size by 15 percent since 1993, equating to a loss of 1% of diameter per year. The finding comes from monitoring conducted by researchers at the University of Berkeley using the Infrared Spatial Interferometer atop Mount Wilson. This shrinkage is all the more stupefying when one considers that recent research places Betelgeuse at a distance of 640 light years, making this bloated star over 5 astronomical units in diameter! AAVSO volunteers that have been monitoring the star have noted that the shrinkage has not been accompanied by a magnitude drop. [Read more...]

April 2009 News & Notes.

The Successful Launch of Kepler: The Kepler space telescope launched successfully last month on March 6th, during a spectacular night launch. Sporting one of the biggest CCD imagers ever to leave Earth, Kepler is bound for an Earth-trailing, heliospheric orbit. Kepler will spend several months staring at a patch of sky in the direction of Cygnus looking for one of the holy grails in astronomy; Earth-sized, terrestrial planets. Stay tuned! This could be one of the potential discoveries of the year!

[Read more...]