Space and astronomy news
[/caption] From a photon’s point of view, it is emitted and then instantaneously reabsorbed. This is true for a photon emitted in the core of the Sun, which might be reabsorbed after crossing a fraction of a millimetre’s distance. And it is equally true for a photon that, from our point of view, has travelled …
Continue reading “Astronomy Without A Telescope – A Photon’s Point Of View”
[/caption] History has proved time and again that mathematical modelling is no substitute for a telescope (or other data collection device). Nonetheless, some theoreticians have recently put forward a statistical analysis which suggests that life is probably very rare in the universe – despite the apparent prevalence of habitable-zone exoplanets, being found by the Kepler …
Continue reading “Astronomy Without A Telescope – The Unlikeliness Of Being”
[/caption] One model of a hypothetical multiverse has, perhaps appropriately, some similarity to a glass of beer. Imagine an eternal false vacuum – that’s a bit like a fluid, though not all that much like a fluid – since it doesn’t have volume, in fact it doesn’t have any spatial dimensions. Then imagine that this …
Continue reading “Astronomy Without A Telescope – Bubblology”
[/caption] Gravitational waves have some similar properties to light. They move at the same speed in a vacuum – and with a certain frequency and amplitude. Where they differ from light is that they are not scattered or absorbed by matter, in the way that light is. Thus, it’s likely that primordial gravitational waves, that …
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[/caption] The very small wavelength of gamma ray light offers the potential to gain high resolution data about very fine detail – perhaps even detail about the quantum substructure of a vacuum – or in other words, the granularity of empty space. Quantum physics suggests that a vacuum is anything but empty, with virtual particles …
Continue reading “Astronomy Without A Telescope – Granularity”
[/caption] One of a number of seemingly implausible features of dark energy is that its density is assumed to be constant over time. So, even though the universe expands over time, dark energy does not become diluted, unlike the rest of the contents of the universe. As the universe expands, it seems that more dark …
Continue reading “Astronomy Without A Telescope – Big Rips And Little Rips”
[/caption] You’ve probably heard of the cosmic microwave background, but it doesn’t stop there. The as-yet-undetectable cosmic neutrino background is out there waiting to give us a view into the first seconds after the Big Bang. Then, looking further forward, there are other backgrounds across the electromagnetic spectrum – all of which contribute to what’s …
Continue reading “Astronomy Without A Telescope – Backgrounds”
[/caption] Molecular clouds are called so because they have sufficient density to support the formation of molecules, most commonly H2 molecules. Their density also makes them ideal sites for new star formation – and if star formation is prevalent in a molecular cloud, we tend to give it the less formal title of stellar nursery. …
Continue reading “Astronomy Without A Telescope – Star Seeds”
[/caption] Cosmic rays are really sub-atomic particles, being mainly protons (hydrogen nuclei) and occasionally helium or heavier atomic nuclei and very occasionally electrons. Cosmic ray particles are very energetic as a result of them having a substantial velocity and hence a substantial momentum. The Oh-My-God particle detected over Utah in 1991 was probably a proton …
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[/caption] The recent WiggleZ galaxy survey data further confirming that the universe is expanding with a uniform acceleration prompted a lot of ‘astronomers confirm dark energy’ headlines and a lot of heavy sighs from those preferring not to have the universe described in ten words or less. I mean how the heck did ‘dark energy’ …
Continue reading “Astronomy Without A Telescope – Enough With The Dark Already”