One Universe at a Time

We now know the scale of the universe to within 1% accuracy.  The results have been presented in an arxiv preprint.  It isn’t yet peer reviewed, but it has been submitted to the Monthly Notice of Royal Astronomical Society, and I suspect it will be accepted soon. 

In 2003 and 2004, the Hubble space telescope looked at a dark patch of sky in the constellation Fornax.  After gathering light for about 275 hours, what it found was an image of more than 10,000 distant galaxies in a patch of sky about the size of a grain of sand held at arm’s length. 

Every now and then rumors of some companion star or planet to the Sun hits the web.  The most infamous of these is the Nibiru hypothesis, which claims that a large planet will sweep into the inner solar system, sending Earth to its doom.  While claims of Nibiru have always been unfounded, there has been legitimate speculation about a possible …

I’ve talked quite a bit about planets around other stars, known as exoplanets.  Most of the exoplanets we’ve discovered are Neptune-sized worlds, but we’ve found exoplanets smaller than Mercury.  But in terms of size, that is about our limit given current technology. Given what we understand about our own solar system, we would expect that these exoplanetary systems also have …

Last year I wrote about how Neptune was discovered by analyzing the motion of Uranus.  After Neptune’s discovery, analysis of its orbit showed possible irregularities that some astronomers argued could be evidence of an even more distant planet, which came to be known as Planet X. 

A new paper in Nature (unfortunately behind a paywall) has announced the discovery of a triple star system consisting of two white dwarf stars and a neutron star.  This has the potential to be a very big deal, because it may allow us to further test general relativity. 

In 1915, Albert Einstein proposed a radical new theory for gravity.  He proposed that gravity could be described by a curvature of space and time, rather than Newton’s theory of forces between masses.  Einstein was already recognized as a prominent scientist for his 1905 papers on the photoelectric effect, brownian motion and special relativity, but no matter how established you …

When Pluto was demoted to a dwarf planet in 2006, there was quite a bit of outrage from the public.  But a similar thing occurred with Ceres in the 1800s.

There is one side of the moon that we always see, and one side that most people have only seen in photographs.  This is because the moon is tidally locked, meaning that one side of the Moon always faces the Earth.