First, I’d like to say I am a big fan of your blog. I’ve always been fascinated with space…and as an “artist”, one of my central themes has been…space (though usually within the context of the Space Race and Cold War era propaganda and advertising) Anyway, I thought I’d share this painting I made, hope you enjoy.
How do you know the EXACT answer to the distance of a light year? Is there no uncertainties anywhere? Could I see the conversion to how an answer came about? Thank you.
The speed of light in a vacuum has been established as exactly 299,792,458 m/s using laser interferometry. Funny thing is, scientists where trying to figure out the exact speed of light before they could decide on a set definition of a meter. In 1983 the General Conference on Weights and Measures decided to let the speed of light itself define the meter as “the length of the path travelled by light in vacuum during a time interval of 1/299,792,458th of a second" Once those standards were established, its a simple conversion from 1 second to 1 year, using a Julian year of exactly 365.25 days (or 31,557,600 seconds)
i was recently talking with a friend and they claim our solar system is neither expanding or contracting because of the way the planets formed in orbit around the sun? i may not be quoting that exact, but i'd like to know if they are right and how is it possible that the rest of the universe is expanding and we are not? i can't imagine how anything could be staying in the same place without expanding or contracting?
The universe (in theory) started with a bang, an explosion, expanding outward, but the sun and planets of solar system began from a spinning cloud of dust and gas that got pulled together by gravity, the Sun’s gravity obviously being strong enough to hold it all together. The solar system can’t be expanding because there was no initial outward velocity (from the Sun out) during it’s formation.
Some of these are a couple years old, so maybe you’ve posted about them before. But these images and informative videos are absolutely beautiful. They’re infrared images from the Spitzer Space Telescope at the California Institute of Technology.
What will NASA do to Discovery, Atlantis and Endeavour as soon as they retire the ships? One of them should be available to visit; would love to see from the inside!
Discovery, the oldest of NASA’s shuttles, has already been promised to the Smithsonian Air and Space Museum in Washington, D.C., leaving Atlantis and Endeavour available for other institutions… The earliest that NASA is expected to announce the final homes for Atlantis, Endeavour and Enterprise is July 2010, which would give the selected museums approximately one year to raise funds and build the required indoor housing for the shuttles.
I’ve heard rumors that the Adler Planetarium in Chicago might put in a very a competitive bid for one of the shuttles. That would be nice, being my home town - there are, after all, quite a few astronauts from around here (Cernan and McDivitt off the top of my head), so who knows?
Incidentally, the is no southern counterpart to the North Star:
It’s just a coincidence that there happens to be a bright star (Polaris) close to the Celestial North Pole. The Southern Hemisphere isn’t so lucky. The only star that comes close is Sigma Octans, which is 1 degree away from the South Celestial Pole. But it’s only 6th magnitude—too dim to see at all except under optimal conditions. Of course, because the stars move in the sky, the fact that we have a North Star and not a South Star is a transient phenomenon. If you wait many thousands of years the situation might be reversed. [source]
thanx for your efforts, your page is a wealth of information.
are you familiar with spaceweather.com and their NEO tracking system?
also the NEAT system (http://neat.jpl.nasa.gov/) is one of the few tangible government expenditures i am proud to be helping to pay for.
Thanks so much! Yes, I visit spaceweather.com often, such a valuable resource - how cool is it to be able to see daily photos of sunspot activity? And I agree, it’s a fantastic use of public money.
Researchers say Pioneer 10, which took the first close-up pictures of Jupiter before leaving our solar system in 1983, is being pulled back to the sun by an unknown force. The effect shows no sign of getting weaker as the spacecraft travels deeper into space, and scientists are considering the possibility that the probe has revealed a new force of nature.
Scientists initially suspected that gas escaping from tiny rocket motors aboard the probes, or heat leaking from their nuclear power plants might be responsible. Both have now been ruled out. The team says no current theories explain why the force stays constant: all the most plausible forces, from gravity to the effect of solar radiation, decrease rapidly with distance.
I am continuously astounded by how little we know about the universe (and planet) that we inhabit. Its humbling.
Using the properties of previously discovered exoplanets, we developed a simple metric of habitability for each planet that uses its mass and temperature to rate it on a scale of 0 to 1, where 1 is Earth-like, and 0 is so very not Earth-like. Plotting these values over time and taking the upper envelope yields a nice march towards habitability.
Using a simple bootstrap sampling analysis, we calculated when a logistic curve fit to such an upper envelope would get to a habitability of approximately 1. And the likeliest time is early to mid-2011, or more precisely, early May 2011. Of course, there are precision considerations, but we are heartened by recognizing that our method shows a 75% chance of such an announcement by the end of 2013 (which is when many astronomers predict such a discovery), and that February 2011 is when we are due for a large release of data and announcement by NASA’s Kepler mission.
An essay in the Ideas section of the Boston Globe this weekend, entitled The Me-Sized Universe, discusses how to bridge the gap between the scale of the universe and the scale within which humans exist. It’s an exploration of some fun facts about the cosmos that are within our grasp and that don’t threaten to overwhelm us too much.
I saw a meteor breaking in two a few weeks ago. I live in a neighbourhood full of houses and trees, so there's not much artificial light invading the night sky. I accidentally looked up and saw something resembling a torch in the dark sky and I could see an equal piece coming out of it. Both pieces burned a few seconds til them were gone. It was very fast and I was very lucky to see it. And I live in a big city!
I think your post are way more interesting that some of the stuff on my dashboard :) so i'm pretty happy to follow you! Also, i saw on t.v. that the moon is getting smaller, is that true? is that possible?! :O
Thanks! We posted about the moon shrinking here. But cut him some slack, he just got out of the pool!