I’m sure you’ve heard the phrase ‘extraordinary claims require extraordinary evidence.’ Such is the case with the search for life. Any scientist who finds direct evidence for the existence of extraterrestrial life had better be sure. And then once they are sure they had better find too much evidence because people will still not believe them. It’s because alien life would be such a monumental, paradigm-shifting discovery, and our entire way of life and system of beliefs would be compromised. For this reason, I simply shake my head every time I see some sensationalized news article about the ‘potential for...
As warm as the temperatures have been recently, it may shock you to learn that today marks the Earth’s Aphelion, or its greatest distance from the Sun in its orbit. This may confuse those that think the Earth has seasons due to its proximity to the Sun. The seasons of Earth are actually due to the tilt of the Earth’s axis, and is a result of how much direct sunlight we receive at any given time of year. It’s one of my favourite trivia questions to ask kids in my planetarium shows, and have them guess when the Earth is...
When the Rosetta spacecraft entered orbit around comet 67P/Churyumov-Gerasimenko, first images captured deep circular depressions among the other surface features. Now that the orbiter has taken significant observations of the comet’s surface, the science team has concluded that these depressions are actually sinkholes that form by the same processes that form sinkholes 500 Million kilometers away here on Earth. Sinkholes on Earth form when subsurface material is eroded away. Though not initially visible on the surface, the material falls deep underground leaving a circular cavern. Once enough material has eroded away, the top of the cavern collapses, leaving a large...
As is the case with any final approach to a new object, the early images, with their horrible resolution, pixelated appearance, and possibly false features due to processing, lead to significant speculation on what we will see as the craft approaches. It was the same a few months ago with Ceres. I personally love the blurry images. It’s a mystery waiting to be solved, and we see it unfold as we move ever closer to our destination. It also reminds me of the early days of the internet I grew up with, using a good old 28.8K modem and waiting 2...
For the last few months, Venus and Jupiter have been visible in the night sky. Venus makes it’s usual 584 day cycle, becoming an ‘evening star’ once again, reaching far from the Sun in the West, while still following our central star. Jupiter has slowly worked its way westward over the past few months, due more in part to Earth’s orbit than Jupiter’s. Finally, the long-awaited conjunction of the planets is nigh, and it offers the best views and photographic opportunities of the year for professional and amateur astronomers alike. What is the brightest object in the sky? The Sun...
It’s not fuzzy caterpillars or any small creatures interacting in a Petri dish. The strange growing and twisting creatures are not creatures at all. Today’s NASA APOD shows a time lapse view of a cluster of sunspots as they pass along the surface of the Sun during its rotation. The total time is about 12 hours for the sunspots to cross the solar surface, yet the video is shortened to a quick minute and a half. The amazing thing to notice is the amazing dance of the sunspots as they shift, twist, merge, separate, and interact with the granular convection cells...
I presume that you know what a leap year is. A year is the amount of time the Earth takes to orbit the Sun, and is measured as 365 days, or 365 rotations of Earth. It is, in reality, a little bit longer. Each orbit of the Sun takes 365.25 days, or 365 days and six hours. So what do we do with that six hours? We ignore it for 3 years. On the fourth year we add up those extra hours and we get 24 hours, an extra day! So we add in February 29th every four years. This...
The Rosetta orbiter lies in a vast empty space, inhabited only by its orbital companion – a 4 Km wide ball of ice and dust, spitting out gases and other material as it is warmed by the Sun’s rays. It’s next mission milestone comes on August 13th, 2015, when the duo reaches perihelion, the closest point to the Sun in their orbit. It will be the first time a spacecraft has the opportunity to study the outgassing and behaviour of a comet as it orbits close to the Sun. So far the comet 67P/ Churyumov-Gerasimenko has been slowly increasing in...
If there’s one true fact about every single gas giant planet ever observed, around the Sun or other stars in the Galaxy, it’s that they all are mainly composed of Hydrogen. Even though the giants of our solar system such as Neptune and Jupiter seem very different, it is Hydrogen that primarily composes them. The difference is in the details though. The blue colour of Neptune is due to the presence of Methane, and even then it only makes up 1.7% of Neptune’s mass. But Hydrogen is light. Wouldn’t giant planets like hot Jupiters lose their Hydrogen from being blasted...
The surface of the Sun is around 5500 degrees Celsius. It’s hot, and it’s a completely different state of matter than the solid, liquid, and gas states that we are used to. However, this is a pretty balmy temperature compared to the solar atmosphere, which is heated to over a million degrees. But how does it get so hot compared to the surface? We know the core of the Sun, where fusion happens, is where temperatures can reach 14 Million degrees, but how is that energy radiated outward? And more importantly, how does it bypass the solar surface and make...
