Andrew

Postcard from the Reef – Crown Toby

Postcard from the Summit – A Very Cold Day

Getting to and from the vehicles was done as quickly as possible, running from door to door. Not only were the temperatures as low as anyone could remember, the wind was adding to the issue, blowing at a steady 35mph. The temperatures reached -8°C (17°F) at night and never rose above freezing during the day. The ice is slowly sublimating in the dry air, but there is still too much on the domes for safe observing.

Now if the wind would obey the posted speed limit…

A Very Cold Day — The remains of heavy ice sublimating in cold, dry air with steady 35mph winds

Kepler and Keck Provide Insights on Enigmatic Planets

JPL press release…

More than three-quarters of the planet candidates discovered by NASA’s Kepler spacecraft have sizes ranging from that of Earth to that of Neptune, which is nearly four times as big as Earth. Such planets dominate the galactic census but are not represented in our own solar system. Astronomers don’t know how they form or if they are made of rock, water or gas.

The Kepler team today reports on four years of ground-based follow-up observations targeting Kepler’s exoplanet systems at the American Astronomical Society meeting in Washington. These observations confirm the numerous Kepler discoveries are indeed planets and yield mass measurements of these enigmatic worlds that vary between Earth and Neptune in size.

Included in the findings are five new rocky planets ranging in size from 10 to 80 percent larger than Earth. Two of the new rocky worlds, dubbed Kepler-99b and Kepler-406b, are both 40 percent larger in size than Earth and have a density similar to lead. The planets orbit their host stars in less than five and three days respectively, making these worlds too hot for life as we know it.

A major component of these follow-up observations was Doppler measurements of the planets’ host stars. The team measured the reflex wobble of the host star, caused by the gravitational tug on the star exerted by the orbiting planet. That measured wobble reveals the mass of the planet: the higher the mass of the planet, the greater the gravitational tug on the star and hence the greater the wobble.

Continue reading “Kepler and Keck Provide Insights on Enigmatic Planets”

Macro Moth

Occasionally the large local hawk moths find their way into my garage. What to do with them?

Take their portrait…

Oleander Hawk Moth — Oleander hawk moth (Daphnis nerii)

Bigeye Emperor

After identifying the juvenile bigeye emperor, I thought I recognized the adult photos in the book. Sure enough, when I looked back through the photos of the same dive there they were…

Jupiter at Opposition

Jupiter will pass through opposition at 09:49HST today.

Jove — Jupiter and the moons Europa, Ganymede and Callisto (left-right)

Jupiter orbits the Sun once every 11.86 years. As the giant planet continues on its way the Earth swings around much faster on our inside track. As a result we lap Jupiter once every 399 days, passing between the planet and the Sun. During opposition Jupiter will rise at sunset, transit at midnight, and set at dawn. This makes the planet available for observation for the entire night.

Look for a bright object rising in the eastern sky after sunset. It is difficult to mistake for anything else, shining at it’s brightest during opposition, a brilliant -2.7 magnitude. For the remainder of the winter and much of the spring, the planet will be quite prominent in the evening sky.

Juvenile Bigeye Emporer

Sometimes you see a fish that is not familiar, asking yourself “What is that?” After so many dives I probably have seen one before, but have not paid any attention to that particular fish in the swirl of color and fish on the reef.

Then comes the challenge of identifying the photo. A first run through the book provided no answers. A second run, checking any families with similar body plans… Nothing. Great, it is probably juvenile that looks nothing like the adult… The adult photo is in the book. More browsing, this time on the Stender’s website. The website often has multiple photos of the same species, including the color variations that come with differing sex and age.

Yup, a juvenile bigeye emperor, it looks absolutely nothing like the adult…

Perihelion

Today the Earth is closest to the Sun, a point called perihelion. We will be about 147,099,000km (91,403,000miles) from the Sun. Compare this to the 152,096,000km (94,508,000miles) we will be at aphelion on July 3rd, a difference of about 4,996,000km (3,104,000miles) occurs throughout one orbit.

It may seem odd that we are actually at the closest for the middle of northern winter, you just have to remember that proximity to the Sun is not the cause of the seasons. The seasons are caused by the axial tilt of the Earth, creating short and long days throughout the year, with a resulting change in the angle and intensity of the sunlight.

2014 Solstices and Equinoxes
	UT		HST
Perihelion	Jan 4	05:59UT	Jan 3	19:59HST
Vernal Equinox	Mar 20	16:57UT	Mar 20	06:57HST
Summer Solstice	Jun 21	10:52UT	Jun 21	00:52HST
Apehelion	Jul 3	22:59UT	Jul 3	12:59HST
Autumnal Equinox	Sep 23	02:30UT	Sep 22	16:30HST
Winter Solstice	Dec 21	23:03UT	Dec 21	13:03HST

Source: NASA Sky Calendar

Quadrantid Meteor Shower Reminder

A reminder that the peak of the annual Quadrantid meteor shower occurs tomorrow morning, during the predawn hours of January 3rd. There should be no moonlight to interfere, no excuse not to get out and watch the sky.