Friday, September 19, 2014

Autumn Equinox Marks First Day Of Fall 2014

CAPE CANAVERAL, Florida -- The 2014 Autumn Equinox falls on Monday, September 22, 2014.  The Autumn Equinox, as pictured in this NASA Earth Observatory photo, is caused by the tilt of the earth's rotating axis. 

According to the U.S. Naval Observatory, the Autumn Equinox, marking the changing of the Seasons from the last day of Summer to the first day of Fall, occurs on September 23, 2014 at 02:29 a.m. Universal Time (10:29 p.m. Eastern Daylight Time on September 22, 2014).

Equinox means "equal night" in Latin, capturing the idea that daytime and nighttime are equal lengths everywhere on the planet. That is true of the Sun's presence above the horizon, though it does not account for twilight, when the Sun's rays extend from beyond the horizon to illuminate our gas-filled atmosphere.

It is the equal amount of day and night in the northern hemisphere for locations like Melbourne, Florida, but also in the southern hemisphere for locations like Melbourne, Australia.

The apparent change in location of the sun and moon, marks important dates for hunting, fishing, and farming.

Of course, it is not the Sun that is moving north or south through the seasons, but a change in the orientation and angles between the Earth and its nearest star. The axis of the Earth is tilted 23.5 degrees relative to the Sun and the ecliptic plane. The axis is tilted away from the Sun at the December solstice and toward the Sun at the June solstice, spreading more and less light on each hemisphere. At the equinoxes, the tilt is at a right angle to the Sun and the light is spread evenly.

2014 Autumn Equinox and 2014 Daylight Savings Time

Naturally, many people think that with the changing of the seasons comes the changing of their clocks at the beginning of Fall 2014.  But this is not the case. 

It is true however, that a helpful way to remember whether to set our clocks ahead or behind one hour during the daylight savings time is to "Fall Back" and "Spring Ahead."

The beginning of Fall 2014 does not mean the end of 2014 Daylight Savings Time.  Daylight Savings Time ends after the Autumn Equinox when days become shorter and shorter heading closer to the Winter Solstice.

So if you are asking, "When does daylight savings time end?" "Do we change clocks when Fall starts?"  The answer is the date Daylight Savings Time (DST) will end for Florida is on Sunday, November 2, 2014.

The rest of the United States will also turn their clocks back on November 2, 2014 with the exception of Hawaii and most of Arizona because those states do not practice Daylight Savings Time.

This means that we gain (not lose) an hour when we turn our clocks back an hour to 1:00 a.m. when our clocks reach 1:59 a.m. on Sunday.

Sunday, September 7, 2014

September's Full Moon Is A Super Moon

CAPE CANAVERAL, Florida -- There will be a Full Moon on the night of September 8, 2014 - but not just any Full Moon - it is a Super Moon that is also known as a a full Harvest Moon.  The Moon will be technically 99.9% full at 1:24 a.m. Eastern Daylight Time on the morning of September 9th.

The moonrise over the Atlantic Ocean on Florida's east coast occurs around 7:18 p.m. EDT (with a few minutes deviation depending on your exact location) on Monday, September 8, 2014.  The full moon will set around 7:35 a.m. EDT on the morning of September 9, 2014.

For those planning a stroll along the beach to watch the Super Moon, this Full Moon brings along with it a 4.5-foot plus high tide that will occur around 7:05 p.m. Eastern Daylight Time, with a few minutes of variation depending on your exact location.

Why is it called a Harvest Moon?

The Harvest Moon gets its name from agriculture.  In the days before electric lights, farmers depended on bright moonlight to extend the workday beyond sunset.  It was the only way they could gather their ripening crops in time for market.  The full Moon closest to the autumnal equinox became "the Harvest Moon," and it was always a welcome sight.

Usually, the Harvest Moon arrives a few days to weeks before or after the beginning of fall.  This year, the Autumn Equinox and changing of the seasons will occur on September 23, 2014.  Equinox means "equal night" in Latin, capturing the idea that daytime and nighttime are equal lengths everywhere on the planet.

2014 Autumn Equinox, Harvest Moon, and Daylight Savings Time

Naturally, many people think that with the changing of the seasons comes the changing of their clocks at the beginning of Fall 2014.  But this is not the case.  
It is true however, that a helpful way to remember whether to set our clocks ahead or behind one hour during the daylight savings time is to "Fall Back" and "Spring Ahead."
The beginning of Fall 2014 does not mean the end of 2014 Daylight Savings Time.  Daylight Savings Time occurs after the 2014 Autumn Equinox and Harvest Moon when days become shorter and shorter heading closer to the Winter Solstice.

What's so special about this September 2014 Super Moon?

According to NASA, a Super Moon occurs because the Moon is in an elliptical orbit around the Earth.  When the Moon is closest, it is at its orbital perigee, which is why a Super Moon is also known as a Perigee Moon.

A full moon at its closest point to Earth definitely will be big and bright. But it won't look much, if any, different than a "normal" full moon and will not have any readily observable effect on our planet except perhaps slightly higher tides.

When is the best time to watch the Super Moon?

Low hanging moons near the horizon appear larger to humans.  So the Super Moon will appear biggest to the naked eye on the U.S east coast during and just after the moonrise around 7:18 p.m. on September 8.

If you live in a different time zones, the time would be the nearly same in your local time if you are on Daylight Savings Times - plus or minus a few minutes.

Where is the best place to watch the Super Moon?

The Super Moon will be visible around the world.  The best place to watch is wherever the viewer has a good view of the horizon, lack of artificial lighting, and no local cloud cover.

Image Credit: NASA


Sunday, August 24, 2014

SpaceX To Delay Launch After Explosion

Falcon 9.   Photo Credit: SpaceX.
CAPE CANAVERAL, Florida -- SpaceX wants to delay the launch of a Falcon 9 rocket scheduled for this Tuesday after a SpaceX test rocket exploded in midair during a test flight in McGregor, Texas last Friday.

"While Friday’s F9R three engine, single stage test article and our launch site in McGregor, Texas are very different from the planned Cape Canaveral, Florida launch of the AsiaSat 6 satellite on the Falcon 9 rocket, we are taking some additional time to review the circumstances that caused the test vehicle to auto terminate to confirm that there is not a risk to orbital flight," Spacex said in a release.   "SpaceX prizes mission assurance above all. This action is consistent with that philosophy. "

As a result, SpaceX has requested a new launch window from the U.S. Air Force for next week’s AsiaSat 6 Mission.  Pending final Air Force approval of this request, the AsiaSat 6 mission is now targeted to launch at 12:50 a.m. EDT, Wednesday, August 27 with a backup launch window on Thursday, August 28.  If approved, the new launch window will open at 12:50 a.m. EDT on August 27 and last 3 hours, 15 minutes.

If all goes as planned, the Falcon 9 rocket will deliver the AsiaSat 6 satellite to a geosynchronous transfer orbit 32 minutes after liftoff.

Launch Weather Forecast

The most recent forecast issued by the U.S. Air Force 45th Weather Squadron predicts a 70% chance of overall permissible weather conditions for the SpaceX launch.  The primary weather concerns for launch are anvil clouds and cumulus clouds. 

Where Can You Watch the SpaceX Rocket Launch?

Due to the late hour of the launch, only areas 1, 2, and 4 on the map are available for launch viewing.

1. Titusville, Florida southward along the Indian River on the east side of US Highway 1.
2. Between Merritt Island and Cape Canaveral along the north side of State Road 528.
4. Along the beaches of Cocoa Beach, Florida (there is metered parking in Cocoa Beach that only accepts quarters, so bring some quarters).

Map of Launch Complex 40 at Cape Canaveral, Florida.  Credit: Google.  Rocket launch viewing locations added by Brevard Times.

Saturday, August 23, 2014

SpaceX Test Rocket Explodes

RELATED STORY: SpaceX To Delay Launch After Explosion

MCGREGOR, Texas -- A SpaceX rocket exploded in midair during a test flight in McGregor, Texas on Friday.

During the test flight of a three engine version of the F9R test vehicle that is the successor to SpaceX's Grasshopper reusable rocket, an anomaly was detected in the vehicle and the flight termination system automatically terminated the mission, SpaceX said in a release.

"Throughout the test and subsequent flight termination, the vehicle remained in the designated flight area. There were no injuries," SpaceX stated.  "An FAA representative was present at all times."

"With research and development projects, detecting vehicle anomalies during the testing is the purpose of the program.  Today's test was particularly complex, pushing the limits of the vehicle further than any previous test.  As is our practice, the company will be reviewing the flight record data to learn more about the performance of the vehicle prior to our next test."

"Rockets are tricky," SpaceX CEO Elon Musk tweeted after the explosion.

Friday, August 22, 2014

Space Shuttle Tiles Installed On Orion Crew Module

Technicians dressed in clean-room suits install a back shell tile panel onto the Orion crew module inside the Operations and Checkout Building high bay at Kennedy Space Center, Florida.  Image Credit:  NASA/Dimitri Gerondidakis

KENNEDY SPACE CENTER, Florida -- Engineers and technicians at NASA’s Kennedy Space Center have finished installing the cone-shaped back shell of Orion’s crew module.  It’s made up of 970 black tiles that should look very familiar because they are the same tiles that protected the belly of the space shuttles as they returned from space.

But the space shuttles traveled at 17,000 miles per hour, while Orion will be coming in at 20,000 miles per hour on this first flight test.  The faster a spacecraft travels through Earth’s atmosphere, the more heat it generates.  So even though the hottest temperature that the space shuttle tiles reached was about 2,300 degrees Fahrenheit, the Orion back shell could get up to 3,150 degrees, despite being in a cooler area of the vehicle.

And heat isn’t the only concern. While in space, Orion will be vulnerable to the regular onslaught of micrometeoroid orbital debris.   Although micrometeoroid orbital debris is too tiny to track, and therefore avoid, it can do immense damage to a spacecraft.  For instance, a micrometeoroid could punch through a back shell tile.  Below the tiles, the vehicle’s structure doesn’t often get hotter than about 300 degrees Fahrenheit, but if debris breached the tile, the heat surrounding the vehicle during reentry could creep into the hole it created, possibly damaging the vehicle.

Debris damage can be repaired in space with techniques pioneered after the space shuttle Columbia accident.  A good deal of information was gathered then on what amount of damage warranted a repair.  But the heating environment Orion will experience is different than the shuttle’s was, and the old models don’t apply, NASA says.

Two one-inch-wide holes have been drilled into tiles on Orion’s back shell to simulate micrometeoroid orbital debris damage. Sensors on the vehicle will record how high temperatures climb inside the hole during Orion’s return through Earth’s atmosphere.  Image Credit:  NASA

Engineers will begin verifying new models when Orion returns from its first flight test in December 2014.  Before installing the back shell, engineers purposely drilled long, skinny holes into two tiles to mimic damage from a micrometeoroid hit. Each 1 inch wide, one of the holes is 1.4 inches deep and the other is 1 inch deep.  The two tiles with these mock micrometeoroid hits are 1.47 inches thick and are located on the opposite side of the back shell from Orion’s windows and reaction control system jets.

“We want to know how much of the hot gas gets into the bottom of those cavities,” said Joseph Olejniczak, manager of Orion aerosciences. “We have models that estimate how hot it will get to make sure it’s safe to fly, but with the data we’ll gather from these tiles actually coming back through Earth’s atmosphere, we’ll make new models with higher accuracy.”

A better understanding of the heating environment for damage on Orion’s heat shield will help scientists and engineers make future decisions about what kind of damage may require a repair in space.

Saturday, August 16, 2014

Snow Cover on Arctic Sea Ice Has Thinned 30 to 50 Percent

Matthew Sturm of the University of Alaska Fairbanks, a co-author of this study, takes a snow measurement on sea ice in the Beaufort Sea in March 2012 during the BROMEX field campaign.

New research led by NASA and the University of Washington, Seattle, confirms that springtime snow on sea ice in the Arctic has thinned significantly in the last 50 years, by about a third in the Western Hemisphere and by half near Alaska.

The new study, published this month in the Journal of Geophysical Research, tracks changes in snow depth over decades. It combines data from NASA’s Bromide, Ozone, and Mercury Experiment (BROMEX) field campaign, NASA’s Operation IceBridge flights, and instrumented buoys and ice floes staffed by Soviet scientists from the 1950s through the 1990s.

“The snow cover is like a shield that can insulate sea ice,” said Son Nghiem of NASA’s Jet Propulsion Laboratory in Pasadena, California, principal investigator for BROMEX and a coauthor of the new study. “In this study, we had thousands of measurements of snow depth on sea ice to thoroughly validate NASA’s aircraft observations. We knew Arctic sea ice was decreasing, but the snow cover has become so thin that its shield has become a veil.”

The researchers found that, since the Soviet period, the spring snowpack has thinned from 14 inches to 9 inches (35 centimeters to 22 centimeters) in the western Arctic and from 13 inches to 6 inches (33 centimeters to 14.5 centimeters) in the Beaufort and Chukchi seas, north and west of Alaska, despite notable uncertainty in the historical estimates. The authors speculate that delayed freezing of the sea surface may contribute to the thinning trend, as heavy snowfalls in September and October now fall into the open ocean.

What thinner snow cover will mean for sea ice is not certain. “The delay in sea ice freeze-up could be changing the way that heat is transported in the Arctic, which would, in turn, affect precipitation patterns. That’s going to be a very interesting question in the future,” said first author Melinda Webster, an oceanography graduate student at the University of Washington.

The research was supported by NASA and the U.S. Interagency Arctic Buoy Program.


Image Credit: U.S. Army Cold Regions Research and Engineering Laboratory 


Forest Fires Cause Melting of Greenland Ice Sheet


Tuesday, August 12, 2014

2014 Perseid Meteor Shower Peaks Tonight

CAPE CANAVERAL, Florida -- The 2014 Perseid Meteor Shower peaks tonight, August 12, 2014.  The summer's best meteor shower won't be as spectacular as previous years because a Full Moon just occurred on August 10, 2014 that will light up the night sky and make it more difficult to see the meteors.

The Perseids Meteor Shower produces more fireballs than any other meteor shower, according to Bill Cooke of NASA's Meteoroid Environment Office.  A fireball is a very bright meteor, at least as bright as the planets Jupiter or Venus.  They can be seen on any given night as random meteoroids strike Earth's upper atmosphere. One fireball every few hours is not unusual.  Fireballs become more numerous, however, when Earth is passing through the debris stream of a comet.  That’s what will happen this August.

Cooke thinks the Perseids are rich in fireballs because of the size of the parent comet. Comet Swift-Tuttle has a huge nucleus--about 26 km in diameter," comments Cooke. "Most other comets are much smaller, with nuclei only a few kilometers across. As a result, Comet Swift-Tuttle produces a large number of meteoroids, many of which are large enough to produce fireballs."


According to NASA, the Perseids have been observed for about 2,000 years.  The source of the annual meteor shower is the debris trail left behind comet Swift-Tuttle.  Each year in August, the Earth passes through a cloud of the comet's debris. These bits of ice and dust burn up in the Earth's atmosphere.  
Most of the Perseid meteors that we observe now were ejected from Swift-Tuttle about 1,000 years ago.  

2014 Perseid Meteor Shower: Where To Watch

The Perseids meteor shower will be viewable almost all over the world but will be best seen in the northern hemisphere.   The major determining factor on where a good place is to watch the Perseids meteor shower will be determined by the viewer's local cloud cover and artificial light pollution.

2014 Perseid Meteor Shower: Where To Look

You can tell if a meteor belongs to a particular shower by tracing back its path to see if it originates near a specific point in the sky, called the radiant. The constellation in which the radiant is located gives the shower its name, and in this case, Perseids appear to come from a point in the constellation Perseus.

2014 Perseid Meteor Shower: When To Watch

The meteor shower will be viewable throughout the night.  Between the hours of 3 AM to 4 AM local time is the best time to watch this meteor shower.  Before midnight the meteor rate will start out low, then increase as the night wears on, peaking before sunrise when the constellation Perseus is high in the sky.

Video and image credit: NASA