A set of questions I get from kids and adults alike while doing my Astronomy in Action planetarium shows consists of the following: Does the Universe have an end? How big is the Universe? Where is the center of the Universe? What is the ‘Observable Universe?’ How is it different from just saying ‘the Universe?’ First of all, let me say that it is really hard to imagine the Universe as it is, even with a solid understanding of large-scale Physics. This is because there is no analogy in our lives, no reference point in our everyday experience. It’s very...
The Universe is big, in case you weren’t aware. It’s the biggest thing we know of, containing at least 100 Billion Galaxies, each with up to 1 Trillion of their own stars. It’s ludicrously large. How do we know its so big? A major project completed in 2001 surveyed the Galaxies of the local Universe, and what was found can be summed up in the video below, from Reddit. The data is from the 2 Micron All Sky Survey (2MASS), whose goal was to map all the galaxies in the known Universe in Infrared. The colours in the above map show...
Quasars are Galaxies with incredibly massive Black Holes at their centre. These Black Holes are fuelled by a swirling disc of material that can be ejected in a long jet along their axis of rotation, all due to the conservation of angular momentum. This accretion disc can be so hot that it causes the central region of the Galaxy to shine more brightly than the entire Galaxy of stars surrounding it. A Belgian team using the Very Large Telescope (VLT) studied a population of 93 Quasars spread over Billions of Light-Years, and noticed that the rotation axes of the Quasars...
I’ve talked about black holes previously, and only in our own Galaxy, and only the big one in the middle, Sag A*. When I speak with the public and with kids about Black Holes, most people never really understand that there aren’t just one or two kicking around, but potentially there are as many as a Billion Black Holes in our own Galaxy! The problem is, we are not very good at finding them. It makes sense, they give off no light, and we can only find them through indirectly measuring their effects on the surrounding environment. We can sometimes see...
Dark Matter; Dark Energy; We basically use the term ‘dark’ as a cool sounding version of ‘We have no clue what this is.’ But Dark Matter is a better name than ‘We haven’t a clue’ Matter. Over the years, Astronomers have been trying to pinpoint what the stuff actually is that seems to permeate the universe and makes up 26.8% of the entire total energy-mass (Compare this to a paltry 4.9% of ordinary matter, ie the stuff we can see). But now, as per usual, theorists have come up with another possibility for the source of dark matter: moderately sized,...
If you’re in Astronomy circles you may have heard about a big cloud of Hydrogen heading toward the supermassive black hole in the centre of our galaxy, Sagittarius A*. The lead up to the cloud approaching the black hole had astronomers buzzing this year, as it would be a direct opportunity for us to see the black hole ‘devour’ the cloud. The black hole would show us some celestial fireworks and give us a huge opportunity to study their behaviour. Astronomers watched closely, and then the cloud passed right by…. We should have seen the cloud torn apart as matter spiralled...
I’ve seen a lot of lovely images from the Spitzer Space Telescope. It takes infrared images and can see the fine structure of galaxies, where stars are forming and where they are not forming. The photos paint a picture of the history and evolution of a galaxy. The latest image released last week shows some amazing features. The Cyan light in the image is a combination of blue and green coloured light representing infrared wavelengths of light at 3.4 and 4.5 microns. This wavelength shows the stellar population in the galaxy. The red light is representing dust features that glow...
Okay so 100 million years seems like a big mistake on the part of Astronomers, but in the astronomical community its a small adjustment. Today the most detailed map of the CMBR ever captured was released by the Planck telescope group at the ESA. Based on 15.5 months of data, it shows the tiny temperature variations that were present when the universe had a temperature of 2700 degrees Celsius and an age of just 380,000 years (trust me that’s small on astronomical scales). This is the point when the dense soup of protons and electrons formed hydrogen atoms, and the universe became transparent. As...
