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Tag Archives: astronomy

Ludi Saeculares: the Transit of Venus

On June 5 (or June 6, depending on which time zone you are in) of 2012, Venus will be seen from the Earth passing over the disk of the Sun. This is not only a rare event, but also one which has been of great historical importance in figuring out how big the Solar System […]

far sight [Q&A]

When it comes to telescopes, a question that astronomers get asked with some regularity is, how far does it see? Abraham Lincoln was once supposedly asked how long his legs were, to which he is said to have answered, “long enough to reach the ground.” Same here. How far can the Hubble see? Far enough […]

Nearest Galaxy [Q&A]

We had a Science Day at Cambridge recently and the SAO ran an Open House where people could come and ask questions of astronomers. One question that came up repeatedly was, what is the galaxy that is nearest to us? It depends on how you define the term. If you are looking for a galaxy […]

Is Dark Matter matter? [Q&A]

Karthik asks, if we convert some Dark Matter to energy, will that be energy as we know it, or Something Elseā„¢? The history of astronomy has been a series of shocks to the ego of mankind, as the importance of our place in the Universe keeps shrinking. First it turned out that the Earth was […]

distance to the Moon [try it]

How far is the Moon? You don’t have to look up the answer in a book. You can measure it yourself, and quite easily at that. You will need an accomplice however. For this, you will need some way to record the precise location of the Moon in the sky relative to the stars in […]

parallax [try it]

How do we know how far anything is? For nearby objects, we can pace off the distance, of course, but what about places we can’t walk to? How does your brain know that that door is 10 feet away without marking it off on a ruler? Suppose you are standing at point A (see figure) […]

solar differential rotation [try it]

The Sun is giant fluid ball of gas. It is not a solid body, and it does not behave like one. In particular, it rotates at different speeds at different latitudes. The website displays daily collections of solar images ranging from visible light photospheric images to magnetic maps to high-energy X-ray images of the […]

amateur X-ray astronomy [try it]

You don’t always need a telescope to do astronomy in your backyard. Data from all the great space-borne observatories (like Hubble, Chandra, Spitzer, etc.) are publicly available for people to peer through and analyze on their own. All you need is a computer and a functional internet connection. The only things stopping people is that, […]

space is big [try it]

Astronomical numbers are difficult for human minds to grasp. And one of concepts I have had the most difficulty in conveying is that space is big. It is really really big. Even the solar system, which is quite minuscule compared to, say, the size of the Milky Way, is mindbogglingly big. And empty. There is […]

residue of stars [Q&A]

Vibha (Poornaprajna PU College) and Tilak (SDM College) ask, there is a lot of stuff in the Universe, especially Hydrogen, where did they all come from? How did they form? Hydrogen is easy (well, in a manner of speaking). It is just an electron paired with a proton. A lot of these were produced during […]