I went to bed last night wondering where the Sun had gone. Then it dawned on me. A little astronomy humor to begin a serious discussion on our life-giving star—the Sun.
Our Sun coalesced out of a vast cloud of gas
and dust some 100 times the size of our solar system roughly five billion years
ago. Gravity contracted this mass until the core of this proto-star reached about
24.5 million degrees Fahrenheit. At that time nuclear fusion began, converting
about 600 million tons of hydrogen to helium per second. This process has been
ongoing since then.
Most folks take for granted that the Sun rises and sets every day due to the Earth’s almost 24-hour rotation. The only change most people recognize is the seasonal cycles caused by the fixed 23.5 degree tilt of our planet’s axis in its orbital path about the Sun. Reference this video to refresh your memory on the Earth’s annual journey.
Continue reading Solar Variability: Our Inconstant Sun
While the Geminid meteor shower of
mid-December reigns supreme as the northern hemisphere’s most productive
display of shooting stars, August’s Perseids, coming in a close second, are the most widely observed meteor shower of
the year. Why? Warm temperatures find families spending more time outdoors
during the summer season enjoying cookouts, camping, or any other assortment of
late evening activities. Normally 60+ green, red or orange Perseids can be
observed per hour during peak activity. Unfortunately, for 2019 a waxing
gibbous Moon (Full on the 15th) will severely hamper observing this
meteor shower which peaks on the night of August 12-13.
However, while moonlight will wash out all
but the brightest meteors before midnight on the night of the 12th,
once the Moon sets around 3:48 a.m. that will leave just over an hour of dark
sky observing time before dawn’s early light begins to brighten the sky.
Somewhat helpful is the fact that Perseus, the constellation from where the
meteors appear to radiate (known as the radiant point), is completely opposite
the sky from the Moon. This circumstance could help extend your window of
opportunity to an hour or two before the Moon sets! Hey, I’m trying my best to
be optimistic here!!
Continue reading Poor Prospects for the Perseids
I hope the weather gods have provided a few
clear nights since my Jupiter observing guide appeared last month. I finally
observed Jupiter at a late June star party Skyscrapers members conducted for
the Jesse Smith Memorial Library in Harrisville on June 28. The four Galilean
moons were easily visible in all the telescopes, as were Jupiter’s striking
banded cloud tops. Regrettably the Great Red Spot was not visible that night,
and my attempts to observe it since my last column have been thwarted for one
reason or another. Fortunately, we have several more months to glimpse this
perhaps dwindling storm.
I’m sure some of you couldn’t resist an
early look at Saturn, even if you had to wait much later in the evening for
this beautiful ringed-planet to rise high enough into the sky to clear summer
horizon haze. Perhaps sky conditions permitted you to obtain marginal views
despite the planet’s low altitude above the horizon within a couple of hours
after sunset. Now that another month has passed, Saturn will have risen much
higher into the southeast sky, thereby allowing for more favorable views. As
promised at the end of July’s column, here is a brief observing guide to Saturn
(our solar system’s most stunning planet.)
Continue reading Splendid Saturn
a few months have passed since the local observatories have had the opportunity
to provide detailed images of some of our planetary companions in the solar
system. When weather conditions have allowed, the Moon has been a good
substitute. When the Moon has not been available, telescope operators have
turned to double stars and faint fuzzies like star clusters, galaxies and
nebulae. However, these celestial objects don’t often elicit the wow factor
that planetary viewing can do. Add some high thin haze, atmospheric turbulence,
a little bit of moisture and light pollution, and it has been a challenge to
provide decent views of the heavens. Our observing opportunities have now greatly
amateur astronomers have been observing Jupiter and Saturn during hours when
most people are in REM dreamland, from now through November telescopes
throughout Rhode Island will focus on exquisite views of these two gas giant
worlds and all their glory. All I can say is, “It’s about time!!” This month’s
column will provide a brief observing guide to Jupiter. Next month I will feature
on June 10 Jupiter reached opposition. That means it rose as the Sun was
setting. This date was also the date of Jupiter’s closest approach to the Earth
for this year—about 397,850,855 miles. By July 1 this distance will have
increased to 403,576,313 miles as the Earth pulls out ahead of Jupiter in our
respective orbits. Fortunately, views of the Jovian system do not suffer dramatically from
rapidly increasing distance.
Continue reading The Return of Jupiter and Saturn to the Evening Sky
we approach the Summer Solstice in the northern hemisphere, this year on June
21 at 11:54 a.m. EDT (Eastern Daylight Time), here in Rhode Island many folks
revel in the extra daylight hours, especially in the evening. Astronomers are
not among those individuals because our skies do not get fully dark until about
10 p.m., and dawn’s early light starts around 4 a.m. That leaves little time to
explore the universe with telescopes and cameras to capture the beauty of the
heavens. Then as the summer months continue, we must contend with high humidity
and pesky mosquitoes.
However, there are a couple of planets we will welcome back to the evening sky over the course of this summer. They are Jupiter and Saturn. These distant worlds reveal much detail in the telescopes at the local observatories.
Continue reading Summer Stargazing