The BAO: Mother of Astronomical Rulers

By Roger Colins

1 AU  = 93 million miles (distance from the Sun to the Earth) _______________________________________________________ 1 light year =  63,000 AU (1/4 distance to nearest star) 1 baryon acoustic oscillation = 500,000 light years (1/5 distance to nearest galaxy) The last one has just been discovered by BOSS, the Baryon Acoustic Spectroscopic Survey, a useful addition to the tool set for measuring the distance between galaxies and the largest unit of measurement devised yet. For those that are unaware, AU stands for astronomical unit and is roughly the distance from the Sun to the Earth, a light year is the distance travelled by light in one year and a BAO, about four and a half times the diameter of the Milky Way. Astronomy has really been ramping up in recent years as the help of technological advances spit ever more sharply sensitive telescopes into space. Backed up with the constantly improved software to scan more space, for more wavelengths spur on the colleges, faculties and space exploration agencies. Currently, so far as is readily observable, Dark Matter has become the most popular target for study since the Higgs Boson and this new ruler; an important measuring stick to mark out the distances between the galaxies and produce practicable data on Dark Matter. Whether or not the BAO has more useful applications remains to be seen though it's entirely possible it will start appearing in high school text books of the next generation.

astronomy science ruler