If You Are Against Nuclear Power

The threat of nuclear war and the increasing rate of climate change means we must walk a thin line when it comes to nuclear power.

When you are told what someone is against, ask them what they are for. If you against nuclear power, what kind of power are you for? Reasonable answers include coal, natural gas, biomass, wind, solar, hydro, or geothermal. However, not all of these answers are equally genuine given the constraints of our world. Renewable energy sources have not historically been economically or technologically viable. Our energy landscape is changing today. A future with more renewables and no nuclear power is possible, yet it may not be the best choice if we are serious about climate change. Nuclear power has often been eschewed out of fear, not practicality or rationality.

Read the rest of this post on the complexities of nuclear power over at at 3 Quarks Daily...

Pale Terraqueous Globes

Imagine the closest star beyond the Sun has a planet orbiting it about the size of Earth. Visualize what your sunset would look like on this distant planet. Perhaps there would be two stars at the center of this solar system. Your sunset would be breathtaking. You could even visualize what the Sun would look like from this planet – just another unassuming star in the sky. You don't have to merely imagine that such a planet might exist. A planet like this really does exist – of course you'd still have to imagine the part where you are on the surface of this world. The Alpha Centauri star system, which is essentially a triple star system of Alpha Centauri A, Alpha Centauri B, and Proxima Centauri has just such a planet. There is a planet in the sky waiting for us at a distance that is just two hundred and seventy thousand times further than the Earth is from the Sun. This planet is near 1500 degrees on the surface, so we wouldn't want to be there, but nonetheless the fact is that astronomers are finding similar planets commonly. There may be a planet just the size of Earth at a nice temperature quite near us galactic speaking. We are searching.

Most planets don't seem to be much like Earth. In fact so far we haven't found a single planet that has a temperature and size similar to Earth, but part of the problem with finding planets is that finding big giant planets – like Jupiter is easy – while small rocky planets like Earth are elusive. But we are on the edge of discovery. All in all Earth-like planets likely abound. In fact with 95% confidence there is an Earth size planet in the habitable zone of a small star within 23 light years of us. The habitable zone is the place where a planet would not be too hot or too cold. A place where a planet wouldn't see its oceans boiled off or frozen into desolate ice tundra. Habitable planets are common in our galaxy and by galactic standards not very far apart. On average Earth-like planets are only 13 light-years apart.  

Continue reading my essay on planets over at 3 Quarks Daily...

Galaxy Formation in the Cosmic Web

The research group I work with has made a fantastic poster about how galaxies form in the cosmic web and how we use computer simulations to understand such a complex process. We made the poster as a form of outreach and in particular for students who may be interested in astronomy research. Please feel free share or print the poster and if there is interest we may consider printing and sending out full size version of the poster for public display. Here is a large pdf version of the poster "Galaxy formation in the Cosmic Web". See a bit more over at Common Observer...

A Comet Unnoticed

Comets have long been portents of change. They challenge the rote repetition of our skies. An astute observer of the sky will perhaps have recently noticed a new object in the sky, a comet, present for the last few weeks (you would have had to look east just before sunrise near the star Spica). This was the comet ISON. But comet ISON, having strayed too close to the Sun, has been mostly annihilated. If there is a comet in the sky and no one sees it, was it ever really there?  

William Carlos William's poem, Landscape with the Fall of Icarus, captures the essence of comet ISON's elusive journey around the Sun. Brueghel, the Felmish Renaissance painter, carefully recorded the event like a faithful astronomer, but the worker is not keen on the sky and Icarus goes wholly unnoticed. It is just the same to the worker, for had they noticed Icarus or not it would likely make no difference to their toils in the field. And similarly ISON went largely unnoticed.

According to Brueghel
when Icarus fell
it was spring

a farmer was ploughing
his field
the whole pageantry

of the year was
awake tingling
with itself

sweating in the sun
that melted
the wings' wax

unsignificantly
off the coast
there was

a splash quite unnoticed
this was
Icarus drowning

ISON made a brief appearance to the unaided eye for a few days before it grazed the sun and then uncoiled itself. But to the learned astronomer ISON is still interesting. Comets are rare objects in the inner solar system so even a dead comet is a chance to learn something, in fact, further spectroscopic observations of this dead comet's remains will continue to tell us exactly what it was made of. There is a legacy here.

I am a contributor over at 3 Quarks Daily now so you can read the rest of the story of this lost comet over there...

Comet ISON in the Sky

There is a new object in the sky. Comet ISON is an icy wanderer making its first and probably last last trip into the solar system from its previous home in the Oort cloud. It will graze by the Sun brilliantly and then depart. As it approaches the inner solar system, it is now inside the orbit of Earth, astronomers have been watching its outbursts of ice and volatile materials which then reflect sunlight and make the comet very bright. It is just visible to the naked eye according to some reports now.  Comet ISON has increased in brightness many times over in the last few days.

We don't know how bright it will get. Astronomers generally just don't know as much about comets as we would like. The comet has undergone outbursts of brightening and dimming, while generally tending to get brighter as it enters in to the inner solar system ISON may become entirely disrupted or get brighter and brighter - the comet of the century. The reason for all this uncertainty is that comets and this object in particular are not well studied. But also it is that comets are not dense rocks, but rather they are loose aggregations of dust, rubble, and ices. Tidal forces and heating of the ices can literally unbind entire comets. I haven't been able to see it for myself yet, it hasn't been quite visible because it rises so late I think.  Currently, if you want to see comet ISON from North America look east right before dawn as it passes Mercury. Read the rest of my post on comet ISON over at Common Observer...

Common Observer, uncommon observations

I have a new online project and venue that I have launched! Common Observer is a collaborative online venue of science, art, philosophy, and culture. The tagline is "Common Observer, uncommon observations." The idea is that we must reason as if we are the most common observer, but that doesn't preclude uncommon observations. An uncommon observation is something that challenges our human condition of common observation. A poem, a theorem, a dance, an equation, a painting, a story, a novel, or a theoretical truth may all be uncommon observations about the world we inhabit.

Yet fear not, I will still post on The Astronomist, in particular I will cross post any original scientific content I create. The reason for this shift of focus is at least two fold. First, it is hard to find time to generate original thoughtful content while finishing a PhD so Common Observer will have more aggregated content. Second, while so many people love astronomy, I feel a broader forum of wider interests will better grip reader's attention, as well as my own attention.

I hope that Common Observer can be a successful collaborative project. In order to realize that goal I am currently searching for culture, art, philosophy, or poetry contributors. So please check out the new project, share it with friends and colleagues, or contact me if you have inclinations to collaborate. Follow Common Observer on twitter, subscribe to the RSS, or just visit the site often. Thanks for the continued support. 

In the Dark

Dark matter is the commonest, most elusive stuff in the universe. Can we grasp this great unsolved problem in physics?

The world we see is an illusion, albeit a highly persistent one. We have gradually got used to the idea that nature’s true reality is one of uncertain quantum fields; that what we see is not necessarily what is. Dark matter is a profound extension of this concept. It appears that the majority of matter in the universe has been hidden from us. That puts physicists and the general public alike in an uneasy place. Physicists worry that they can’t point to an unequivocal confirmed prediction or a positive detection of the stuff itself. The wider audience finds it hard to accept something that is necessarily so shadowy and elusive.

I just published this article in Aeon Magazine, read on!

ALMA in Search of Our Cosmic Origins

ALMA (the Atacama Large Millimeter/submillimeter Array) is the most complex and ambitious astronomical observatory ever completed. And it is officially completed. Last week the telescope array was inaugurated at an official ceremony; all the major systems of the telescope are now operational. ALMA is an important instrument for astronomers because it allows us to see in the submillimeter wavelength band where stars formation in distant galaxies are evident. In addition to seeing distant galaxies dusty obscured regions of space can be explored with this instrument. In order to get such a fantastic view of the universe astronomers have had to build the telescope array at an elevation of 5000 meters (16,400 feet) in the dry Atacama desert because the atmosphere would otherwise (particularly water vapor) block the light at the these wavelengths. There have been many engineering and management hurdles in the completion of ALMA so the success of the project deserves recognition. ALMA is an expensive partnership between Chile, Europe, North America, and East Asia that represents what is hopefully the beginning of many more massive multinational collaborative astronomical observatories. The European Southern Observatory who does a lot of the primary management of the observatory also does a lot of great work generating public outreach. They have produced this video which presents the history of ALMA from the origins of the project decades ago to the recent first science results.

Alma means soul in Spanish. A beautiful name for the observatory that looks so serene as it gazes up at the Milky Way discovering our cosmic origins.