The moon orbits around the earth every 29.5 days and since our months typically have 30-31 days that leaves some leftover time (0.5-1.5 days). Eventually that adds up and we get an extra cycle in one month, and that means an extra full moon. Typically, months only get one full moon and so having two is pretty rare, happening every 2.7 years.
Hence, the phrase, “once in a blue moon,” which is a lot like saying “once in about 3 years”.
I love this stuff (orbits, planets, stars) and have been a star-gazer since I was a kid. If you are too, then you can enjoy the “blue moon” this Friday, August 31, 2012.
Yep, it’s been around three years since the last one (2.67 years to be exact, the last blue moon was on New Year’s Eve – Dec 31, 2009). I also think you should try, at whatever the cost, to say “once in a blue moon” about something. Think of something you know you won’t do or won’t happen until July 2015 (the next blue moon).
A newly discovered cluster of galaxies, more than 5 billion light years from Earth…is among the most massive clusters of galaxies in the universe, and produces X-rays at a rate faster than any other known cluster.
It also creates new stars at an “unmatched” pace of more than 700 per year, said Michael McDonald. “This extreme rate of star formation was unexpected,” he said during a NASA news conference Wednesday, noting that the Milky Way forms just one or two stars a year.
In addition to being massive, unique, and the biggest star-nursery in the universe, this area, called Phoenix, also helps theorists with something, the galactic cooling problem.
For years scientists have been coming up with explanations for how stars are formed. The earliest being a mass of molecules would collapse in on themselves as fusion begins. The mass would then accumulate until its gravity becomes strong enough to spin, turn into a sphere, and pull on everything around it, collecting planets, asteroids, and other debris into its solar system.
But, this doesn’t take into account thermodynamics, specifically why doesn’t the star expand as it heats up. Indeed, several half-stars were observed in the universe stuck in this state of expansion unable to contract into the ultra-compact ball of a star.
That’s where a new theory comes in, the galactic “cooling flow”.
**There appears to be no name for the theory, all references are to a general theory theory of star formation.
This says the creation of stars is a lot like an explosion, with an initial burst of heat which then dissipates bringing cool air back into the explosion zone. In this case, thermonuclear fusion ignites much of the galaxy and begins sucking into the center lots of mass, including the surrounding galaxies.
As the (star) forms, this plasma initially heats up due to the gravitational energy released from the infall of smaller galaxies.
As the gas cools, it should condense and sink inward, a process known as a “cooling flow.” In the cluster’s center, this cooling flow can lead to very dense cores of gas, termed “cool cores,” which should fuel bursts of star formation in all clusters that go through this process. Most of these predictions had been confirmed with observations – the X-ray glow, the lower temperatures at the cluster centers – but starbursts accompanying this cooling remain rare. – TG Daily
A step forward in our knowledge of star formation, but something tells me we are not there yet.
The largest full moon of 2012 happens this Saturday, but it’s OK if you don’t really notice. The moon doesn’t really get bigger, it just gets closer to Earth.
At 8:40 p.m. Pacific Time on Saturday, according to the Griffith Observatory Sky Report, the moon will be at its closest point in its orbit to the Earth this year. (Accounting for the time zone difference, European moon-watchers will see it Sunday.) To be precise, Earth and moon will be just 221,801 miles apart — more than 17,000 miles closer than average.
NASA’s Science News calculates the moon’s appearance Saturday will be “as much as 14% bigger and 30% brighter than other full moons of 2012.”
Some call what’s known as a perigee full moon a “supermoon.”
The peak of the Lyrid meteor shower will be viewable all over the world this Saturday night. With the best rates seen just before dawn. The Lyrids can offer a shower of activity, with peak meteor rates between 10-100 per hour. This year Dr. Cooke estimates that the rate will be around 15 per hour, though he is hoping for a surprise increase above this!
The Lyrids are pieces of debris from the periodic Comet C/1861 G1 Thatcher and have been observed for more than 2,600 years. In mid-April of each year, Earth runs into the stream of debris from the comet, which causes the Lyrid meteor shower.
Also, NASA plans to have an expert chat during the event, where you can ask questions to meteor experts and view live feeds:
If you’re looking for a fun way to spend an early spring weekend, make plans to stay “up all night” with NASA experts to watch the Lyrids brighten the skies. On Saturday, April 21, from 11 p.m. to 5 a.m. EDT, meteor experts Dr. Bill Cooke, Danielle Moser and Rhiannon Blaauw from NASA’s Marshall Space Flight Center will answer your questions about the Lyrids via a live Web chat.
Joining the chat is easy. Simply visit this page a few minutes before 11 p.m. EDT on Saturday, April 21. The chat module will appear at the bottom of this page. After you log in, wait for the chat module to be activated, then ask your questions!
A live video feed of the Lyrid meteor shower will be embedded on the page on the night of the Web chat, and there will be alternate allsky views being streamed from the allsky camera network.
The year was 1998 and two highly competitive groups of astronomers were each rushing toward the same goal: they hoped to hunt down the effects of gravitational braking in the universe. Ever since astronomers had accepted the idea of the Big Bang, they had been out hunting for its subsequent cosmic deceleration.
While the Big Bang blows space apart (it literally stretches all points of space-time away from each other), the gravitational pull of matter should, over time, slow down that initial burst of cosmic expansion.
As data was gathered and analyzed, both the Harvard and Berkeley groups were stunned to find no evidence for deceleration. Instead, everything pointed in the opposite direction.
According to observations, the expansion of the universe was speeding up — it was accelerating. Cosmic acceleration became big news.
Which means there exists a Dark Energy pushing the universe outwards:
In 1999, the newly discovered cosmic acceleration made it clear that some form of anti-gravitational energy had to exist. As nothing was known about this energy…it was called Dark Energy
The discovery of cosmic acceleration and Dark Energy upended cosmology almost overnight.