November 18, 2017

June 2013: Life in the Astro-BlogoSphere: Spoilers or Just Spoiled?

For your viewing pleasure

(and to set your mind at peace)…

a rising waning gibbous Moon.

(Photo by Author).

It’s a tough vagabond life, being a science fiction critic these days. As the summer sci-fi blockbuster season rolls on, our fancy turns to movie reviews. Hey, I do it, we all do it. Science writers just can’t resist the urge to mention Harry Potter whenever a science story hints at the promise of invisibility, or segue into a sidebar about the astronomical plausibility of the worlds depicted in The Game of Thrones. We all chase after the all-mighty SEO, baby. [Read more...]

How Far? Measuring Astronomical Distances.

But a nearby stepping stone; our humble moon. (Photo by Author).

   You hear it at every star party. It’s probably the next biggest question right behind “is there life out there,” and “can you really see the flag the astronauts left on the moon with that thing?” Just how do we know how far away things are in the universe? After all, men have never ventured beyond the Moon; and it has only been in the past half century that we have sent embassaries on trajectories that will escape our solar system… just how do we measure these enormous distances with any confidence?
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20.02.11: A Snapshot of a Primordial Galaxy.

When it comes to the Hubble Space Telescope, the hits just keep on a’ comin’… earlier this year, researchers pushed the refurbished telescope to its limits, revealing what may prove to be most distant galaxy (or indeed object) yet seen. At 13.2 light years distant, the smudge pictured above would have been from a time when the universe was only about 500 million years old.

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Review: How Did the First Stars and Galaxies Form? By Abraham Loeb.

Out Now from Princeton University Press!

One of the crucial questions in modern cosmology is: why is there anything at all? Why are we here to admire the cosmos, and create books and blogs about how clever we are to figure it all out? Why didn’t the early universe promptly annihilate itself in a massive matter/anti-matter collision? [Read more...]

02.05.10- Star-birth in the Early Universe.

(Credit: NASA/Hubble StS/Steward).

(Credit: NASA/Hubble StS/Steward).

A comparision of an ancient spiral galaxy in visible (left) and Infrared (right).

   Astronomers are shedding new light across the spectrum on an old cosmological mystery. It’s well documented that the rate of star formation today is much less than what it was early on in the history of the universe; what isn’t completely understood is why. Was there simply an abundance of star forming material available, or was the process of star formation more efficient? Either trend may have a huge significance as to how the current and future evolution of the universe plays out; stars such as our Sun are metal rich and formed as a result of the recycling of cosmic material from that first primeval generation of stars. Even non-fusion sustaining bodies such as the Earth, Sandra Bullock, and your IPad owe their elemental composition largely to those original stars.  Now, a team led by Michael Cooper of the University of Arizona’s Steward Observatory is tackling the dilemma from a fresh angle. The galaxies in question are about 4 billion years old; the universe is an estimated 13.7 billion years of age. In that tender young era, the rate of observed star formation was about 10 times what we see today. Traditional surveys have looked at larger, brighter, and more easily observable galaxies in the energetic throes of star formation. But is that the best approach? This method largely ignores the vast population of fainter, harder to spot galaxies. “It is a little like studying only individuals who are seven feet tall instead of those who fall in a more common range of height,” stated Cooper. Their unique approach has been to examine a selection of average galaxies culled from 50,000 objects to study across a range of wavelengths. Instruments called into action included the Hubble and Spitzer Space telescopes as well as an array of ground-based radio telescopes. Analysis across the spectrum shows that a much greater concentration of gas and dust was available to fuel star formation than what we see today; these galaxies also really light up in the radio and infrared, as pictured above… could we be looking at snapshots resembling our galaxies’ grandparents?

Review: The Five Ages of the Universe by Fred Adams and Greg Laughlin.

A cosmological classic!

A cosmological classic!

  

   This week, we’re going to look at a classic book on cosmology that is both fascinating and frightening. About 10 years ago, I read the Five Ages of the Universe by Fred Adams and Greg Laughlin.  This book built upon information gathered in the swiftly growing field of cosmology, a science that has just come into its own from one largely of late night philosophy to one of hard science with real observational data. Five Ages does nothing short of trace the history of the universe from its first moments to its logical end, or lack thereof. The discovery that we appear to live in an open universe that will indeed expand ad infinitum holds some very bizarre and disconcerting conclusions, all of which the authors explore in vivid detail using the most up-to-date data available. It’s strange to think that we may occupy a tiny sliver of space and time where life can occur, and a vast, infinite stretch of nothing may be in store. However, the authors are careful to make every attempt to abandon their own human bias towards the current era, and instead look at subsequent epochs on their own terms.     

 

When dealing with a topic as expansive as the history and fate of the universe, one has to become accustomed to discussing extremely large numbers. Creationists aside, we live in a universe that is about 13.7 billion years old, give or take about 100 million years. But that is peanuts compared to the gargantuan timescales discussed in this book. Instead, the authors resort to what are termed cosmological decades, (henceforth called CDs) exponential scales where each decade is ten times longer than the last. Thus we are said to exist at the very beginning of the 10th decade, or 1010, which began 3.7 billion years ago and will last until decade 11 over 96 billion years from now. And trust me, the time scales just get larger from there…

The first era covered is termed the primordial epoch, from the moment time and space began until CD 6. During this time of rapid inflation matter coalesced via nucleosythesis, the cosmic microwave background separated out the cooling universe, and the first stars began to shine.

The next era explored is our own, termed the stelliferous era. This is the time we see today and are most familiar with. Stars shine via fusion, galaxies collide, and the processes that power life that is possible to contemplate the wonder of it all and write books (and blogs about books!) is possible. During this period, which is expected to last up until about CD 15, stars will pass through their life cycle until the universe is littered with white dwarfs, pulsars, and black holes. Miserly red dwarf stars, with an expected fusion producing life span of up to about 10 trillion years are expected to be the last stars to go. Then the universe gets really weird…

From CD 15-40 we enter what is known as the degenerate era, a time when white dwarfs turn black, protons decay, and dark matter annihilates the galactic halo. Perhaps an occasional brown dwarf pair will merge in this far-off time and an old school star will shine briefly in the void. But by CD 40, the start of the black hole era, only the stellar remnants of black holes will remain. Even these are anticipated to decay via the process of Hawking radiation with even one million solar mass monsters dissipating after around CD 83. Axions are also predicted to decay into photons at about this time.

 

Of course, what happens during the final dark era of about CD100 on is highly speculative. Will time itself cease to exist? Will quantum fluctuations randomly spout new universes? Will a sort of cosmological phase transition reconstruct our present universe? Keep in mind, long before this time, the edge of the observable universe will have expanded to a mindboggling point, as if it’s not brain blowing big enough now. In fact, the distance between whatever passes for individual particles in the far off dark era will be larger than the observable universe today!

Read The Five Ages of the Universe to gain a cosmic perspective on the consequences of just what living in an infinite universe might mean. Each chapter also opens with an engaging “you are there” narrative to help gain a perspective on these alien realms through the forces propelling the universe through its transitions. Perhaps I would first read Stephen Hawkings’ landmark A Brief History of Time to provide some background, and then follow up Ages with Douglas Adams Hitch-hikers Guide to the Galaxy as a way to cheer oneself up as to the inevitability of it all!           

universe1_f

You are here… (credit: NASA/WMAP).

Review: Burnham’s Celestial Handbook.

A few decades back, I mentioned to a friend at a local planetarium of my enduring interest in astronomy. “Surely, then, “ he said pulling out a three volume set, “you have these…” I did not at the time, but I had indeed heard the legends. The books were Burnham’s Celestial Handbook, a three volume compendium on observational astronomy. A few weeks back we did a piece on the man, Robert Burnham Jr. and his tempestuous life; now I’d like to break with tradition a bit a provide a review of this indispensable astronomical classic. [Read more...]

Review: Bang!

 

 

Think hard rock and astrophysics don’t mix? Think again. Recently, we had the pleasure of reading Bang! The Complete History of the Universe,” by astronomy heavyweights Brian May, Patrick Moore, and Chris Lincott… [Read more...]

December 2008: News & Notes.

Mysterious Missing Gamma Rays: Gamma rays have been “hot” (pun intended) in the news as of late. Now, decades after their initial discovery, scientists are asking themselves; where are they? Specifically, long term bursts, those lasting seconds or more seem to be missing from the universes’ earliest epochs.

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My Personal Connection with the Universe

Even since I was young, I’ve looked towards the stars. One of my earliest memories was looking up at the cresent moon, in conjunction with some bright planet (probably Venus) as my Aunt Lorraine carried me up to our apartment in Mapleton, Maine. Not that I knew what any of these objects were. I just thought that they were bright and shiny, and due my rapt attention. All these years later, a rising moon still draws me outdoors. [Read more...]