Astronomers Reach Verdict On Distance From Earth To Sun, Finally
By Roxanne Palmer | September 19, 2012 2:21 AM EST
You can stop worrying about calculating your distance from the sun - astronomers have taken care of it.
In August, the International Astronomical Union -- which you may remember as the body that demoted poor Pluto to dwarf planet status in 2006 -- voted to fix the astronomical unit, which designates the distance between the sun and Earth, at 149,597,870,700 meters (92,955,807.273 miles). The new fixed distance replaces a complicated equation that served as the previous definition of an astronomical unit..
One might think that astronomers would have had the whole 'distance from the Earth to the sun' matter locked up a while back, but it turns out that the astronomical unit has been a contentious figure for centuries.
17th-century astronomers Giovanni Cassini and Jean Richer pegged the distance from the Earth to the sun as 140 million kilometers, just nine million kilometers off from the now-official figure. They calculated the astronomical unit by using observations of Mars from two different spots on Earth, then used the difference between those two observations to calculate our distance from Mars, which they then used to determine our distance from the sun.
But as technology advanced, scientists found even more precise ways to set the astronomical unit.
The previous formal definition of an astronomical unit, adopted by the IAU in 1976, was slightly less accessible to the layperson: "the radius of an unperturbed circular orbit a massless body would revolve about the sun in 2*(pi)/k days (i.e., 365.2568983... days), where k is defined as the Gaussian constant exactly equal to 0.01720209895."
One problem with the old definition was that it ran into complications thanks to general relativity. Observations on space-time are affected by where you measure them from, so the result you get from the previous definition of an astronomical unit differs by about 1,000 meters if you calculate it from the surface of Jupiter instead of Earth, German astronomer Sergei Klioner said in an interview with the journal Nature.
Having a fixed number for the distance between the Earth and the Sun may mess with some computer programs that use the old definition, but it won't muck up any of NASA's spacecraft, since they measure distance in space directly. The new standard, however, is easing a lot of headaches for astronomers.
"I'm happy that I don't have to explain it to my students any longer," Klioner told Nature.
To contact the editor, e-mail:
Most Popular Slideshows
- Prince William & Kate Middleton Caught Flirting In A Countryside Dinner Date [PHOTOS]
- Kate Middleton’s Mom Accused Of Being A Social Climber, Prince George Not Seen By Relatives
- Prince William & Kate Middleton Boards London Train in Casual Disguise, Royal Couple’s Incognito Plan A Huge Hit [PHOTOS]
- Angelina Jolie & Brad Pitt’s Top Secret Wedding Tramps Jennifer Aniston’s ‘Friends’ Reunion & Pregnancy Talks [PHOTOS]
Join the Conversation
- UFO Sighting in Australia: A Mysterious 'Flying' Object With Changing Colors Observed[Watch Video]
- Volcano Eruption In Iceland: Lava Erupts More Than 50 Meters High, Prompts Aviation Alert [Video]
- Artificial Micro-Humans to Replace Animals in Lab Tests: 90 Million Animal Lives Would be Saved
- Images Of Solar Flare Captured By NASA [Watch Video]
- Volatile Volcanoes Are Waking Up
- 5.5-Inch iPhone 6 is iPhone Air on Sept 19 Release Date: 5 Things to Consider Before Buying
- Pricey iPhone 6 on Release Date Likely but with 3X Retina Resolution & Mobile Payment Service – Reports
- Nexus 6 Release Date Update: Moto X+1 Look Leaked, Nexus X or Shamu Moved to Demo Phase
- Google Nexus 8 Confirmed as HTC T1 aka Volantis/Flounder with Freshly-Leaked Specs & Features – Reports
- Europe, US Next on ISIS’ Hit List, Says Saudi King; Seized ISIS Laptop Reveals Terrifying Bio-Warfare Plans
- iPhone 6 On Release Date To Feature Qualcomm MDM9625M LTE, 1GB RAM, Mobile Payment Deal With AMEX, 1334x750 Display
- Leaker of Actresses Nude Photos Accepting PayPal Donations in Exchange For Posting Alleged Sex Video of Jennifer Lawrence, Has Naked Pictures of 100 Hollywood A-Listers