The Gravity Wave Era

I saw an article last night about gravitational waves, that a black hole merger was detected by not just the Laser Interferometer Gravitational Wave Observatory (LIGO), but by another project altogether, the Virgo collaboration.  This is the first gravitational wave detection confirmed by two separate groups, and it marks the beginning of a new era of experimental science, the first in astronomy in over two decades. Around 1.8 Billion years ago, to black holes merged in a faroff galaxy.  They had masses of 31 and 25 times that of the Sun, though with their incredible density they would each be...

Einstein’s Final Riddle

Why does the Universe expand the way it does? Why does it accelerate? Einstein’s equations offer an explanation of gravity that works on the scale we know, but do they work on the grandest scales of space and time? Humanity now has a way to find out. The General Theory of Relativity predicts the behaviour of gravity, and includes a term known as the cosmological constant.  Einstein added this term to make the universe static and unchanging, as he believed it was.  But when the expansion of the universe was discovered by Edwin Hubble, Einstein regarded it as ‘the greatest blunder...

Astrophotography: Sagittarius and the Galaxy

The challenge of learning astrophotography, and photography in general, is two-fold.  There’s the work you do at the eyepiece, requiring you to choose the right settings for the right shot.  Then there’s the work you do at the computer screen, the post-processing and adjustments.  Ultimately the more important one is the camera work.  If you take a bad photograph, no amount of post-processing will help you, even if you are an expert at it.  It’s like the image is the cake, and the processing is the icing.  No matter how much icing you cover it with, a bad cake is...

Reflection in a Dark Universe

Like lighthouse beacons in a dark ocean, stars act as tiny islands in the vast universe.  Producing light at the atomic level from the powerful release of energy through fusion, they are the engines that drive the formation of new elements.  But in the darkness there are plenty of other hidden objects that are cold and give off little to no light.  Yet many of them are easily seen.  Here’s Why! The first thing to think about is infrared light, the radiation given off by warm objects.  Large planets and brown dwarf stars are very bright in infrared, much brighter...

Atmospheric Spectral Shift

Why does the Sun seem red near the horizon? Why does the Moon do the same?  We know the Moon isn’t actually changing colour, and the Sun isn’t either.  So what is happening to the light? The first thing to note about the image above is that the size of the Moon doesn’t change, showing that the well-known ‘Moon Illusion,’ where the Moon appears larger near the horizon, is just that – an illusion.  The second is of course the gradual change in hue as the Moon rises. The reason for the colour shift really has nothing to do with the Moon...

Everlasting Light

Light is beautiful.  It illuminates a world of beauty for us to appreciate while giving us a tool to decipher the riddles of the universe.  In astronomy, it’s always about more photons! Because more photons = more data = better results.  But in an increasingly technological world, more photons can be a bad thing.  Especially when the artificial photons overpower the natural. I was lucky to spend most of my youth living away from the bright lights of the city, but with the sprawling metropolis of Toronto to the South, I could always see the orange glow that blocked out...

Black Holes ARE Dark Matter?

Dark matter could be almost anything.  With little data other than how much total dark matter mass exists, we can’t decode much about what individual chunks of dark matter might be made of.  I’ve talked before about Massive Compact Halo Objects (MACHOs) and Weakly Interacting Massive Particles (WIMPs), but these are just two possibilities.  Other theorists have talked about Modified Newtonian Gravity (MNG), where gravity may work differently on the grand scale than it does on our small Earth scales.  Or perhaps it’s something I haven’t seen before.  Maybe what we call dark matter is just a large population of ancient black holes....

New England Fireball

Space dust hits the Earth every day in the form of meteorites. As much as 300 tonnes of the stuff falls to the Earth each day.  Of course, most of it is dust or small rocks, and goes unnoticed by the majority of people.  But every so often, a larger rock plummets to Earth, and if it’s big enough, it will make it’s presence known.  One such meteor flew through the atmosphere less than 48 hours ago in the Northeast USA. The bright flashes occur when a space rock, called a meteoroid, hits the atmosphere of the Earth, which rapidly...

Twilight Rocket Trail

Have you seen a gorgeous red sky in the evening, just after sunset? If it’s cloudy, the effect becomes even more spectacular.  The Sunlight reflects off the clouds and back down to the ground, creating the calm of twilight.  Clouds only go so high, so as the Earth continues to turn and we go deeper into nighttime, the glow disappears.  But sometimes it sticks around a bit longer. During a rocket launch at dusk, the exhaust trail from the rocket climbs into the upper atmosphere, far above cloud layers.  It can reflect sunlight, with the shape of the particles refracting...

Falcon Flight to the Galaxy

In the APOD photo from May 14th, it is easy to imagine the rocket launching far away into the galactic disk.  Sadly the rocket can’t traverse the thousands of light years to reach the distant stars, and is restricted to orbiting the Earth. Another beautiful part of this image is the technique involved in producing it.  It required combining two exposures. The first, with low sensitivity to capture the orange rocket trail of the Falcon 9.  The second with high sensitivity and a longer exposure time to capture the faint light of the Milky Way galaxy beyond.  The result is...