Rosetta’s Final Mission

Tomorrow, one way or another, the ESA’s Rosetta mission is coming to an end.  In a final maneuver, the craft will attempt to land on the surface of the comet, following in the footsteps of the Philae lander, though hopefully with more success. The video shows the final orbit plan, and really highlights how amazing mission scientists are to be able to plan a landing site when the comet is rotating so quickly, relative to the craft’s motion. You can follow the link to watch the live broadcast of the event here.  The mission will end around 7:20am EST tomorrow,...

The How and Why of Planet Nine

It hasn’t been found yet – let me make that clear.  But with evidence that it should exist, astronomers are looking more closely at the proposed planet nine and how it might have formed, and how it could have ended up in such a distant orbit. When you start to think about how a planet ten times the mass of Earth could have ended up more than ten times as far from the Sun as Neptune, a few scenarios pop into mind: It was formed in the inner solar system, where interactions with gas giants or another star pulled it out It formed...

Don’t Blink or You’ll Miss it

Have you ever seen a picture of a comet or asteroid in the sky against a background of stars? Here let me show you. Can you spot the asteroid? Okay I confess there is no asteroid in the image above, but if there was you’d believe me because an asteroid in this image would be indistinguishable from the stars.  They are all points of light, so how can you tell them apart? There’s something that separates asteroids, comets, planets, and all other solar system objects from background stars in an image. When you’re driving in a car and you look to the...

Comet or Asteroid?

What is the difference between a comet and an asteroid? The typical response is that an asteroid is rocky and a comet is icy/gassy.  Further than this, asteroids typically orbit closer to the Sun than Neptune, and comets orbit beyond this loose dividing line.  But as with everything in nature, there are often exceptions to the rule. C/2014 S3 PANSTAARS is classified as a weakly active comet, originating in the Oort cloud with an orbital period of 860 years.  As it approached the Sun, astronomers noticed that it was lacking the characteristic comet tail, resulting from the blast of solar radiation upon approach to the...

Cometary Chaos

In 2014, comet C/2013 A1, known as sliding spring, came within 140,000 Km of the planet Mars.  This is a bit more than a third of the distance from the Earth to the Moon.  Comets are small, so gravitationally this interaction was insignificant, but from an electromagnetic point of view, things were shaken up big time! Comets are small, relatively speaking.  A typical comet is a few kilometers across, about the size of a big city.  But with sunlight melting ices and liberating gases and dust from the comet’s interior, the part of the comet we see in the sky,...

1000 Things You Didn’t Know About The Universe #6: Earth’s Moon is Big

When we see the Earth’s only Moon up in the sky, we often think about how small it is.  It’s only about 1/4 the diameter of the Earth, and at a distance of 384,000 Km, it looks small in the sky.  But often size is entirely a matter of perspective.  What we compare something to, that’s what determines it’s size.  When the Moon is high in the sky we easily compare it to the size of the window we are looking through, or to a nearby tree, or our outstretched hand.  All of this can make the Moon seem pretty tiny....

More Than Just a Big Dipper

The big dipper is visible every day of the year from the Northern Hemisphere.  It’s easily recognizable and most people have spotted it at least once in their life.  But most people also assume that it is just a boring collection of stars where nothing interesting ever happens.  The big dipper is so much more than a simple spoon in the sky, especially right now. The well-known asterism, part of the much larger Ursa Major constellation, is home to many visible deep-sky objects, though right now it is visited by the comet C/2013 US10 Catalina, close to the visible binary...

This May be the End for Philae

I remember being so happy back in mid-2015 when I heard that ESA made contact with the Philae lander.  The little lander that could was thought to be lost to the cold of space, not receiving enough sunlight to power itself.  But when the comet approached the Sun, the sunlight became intense enough to wake it back up and allow it to move some of the data it captured.   But now, as the comet 67P has moved further from the Sun in its orbit, the likelihood that Philae will ever communicate again is slim. When the landing originally happened, the little...

A Comet Tale (Tail)

As we rang in the new year, we were treated to a special astronomical appearance of Comet C/2013 US10 Catalina, close to the bright star Arcturus in the image below.  Also visible near the top is the faint Comet P/19 Borrelly, and between the two comets is a bright meteor that swept through the scene. It’s remarkable to notice the clearly visible tales of Catalina, the blue ion tail sweeping directly away from the Sun due to solar wind pressure, and the dusty white tail marking the path of the comet.  The dust is too heavy to be swept away...

The Unpopular Meteor Shower

Everyone in Canada looks forward to the Perseid meteor shower each August.  The weather is warm, the skies are clear, and they have a high zenithal hourly rate (ZHR).  But once they are done, it’s not long before the weather starts to cool down, Canada moves into Autumn and eventually the deep freeze of winter sends our fine nation into hibernation.  But if you do feel like coming out of your fort this weekend, in an unseasonably warm December, you will be treated to what has often been the best meteor shower of the year: The Geminids. Under ideal conditions,...