By David Ward
Three bright planets will continue to put on a spectacular show for us in the July twilight sky. On the evenings of July 1, Jupiter and Venus slide within a hair’s width of each other. Do not miss this one. Then the pair drift apart but remain near to each other through much of the month.
During the twilight of July 18, look for brilliant Venus and a thin crescent moon floating just beneath. You will need to be able to see low into the west to catch this stunning sight. Dimmer Jupiter will be seen to the right of the pair.
If you have a small telescope or a powerful pair of binoculars, be sure to watch the changing phases of Venus during July. Yes, Venus goes through phases just like our moon because its orbit takes it between Earth and the sun. As it races closer and closer to us during July, you can easily see it as a very thin crescent, just like a tiny moon.
Late in July, Jupiter and Venus, the two brightest planets that will have graced our evening skies for months, will make their exit into the sunset glare. Look for them again in the east at dawn in September.
With Jupiter and Venus low in the west, the planet Saturn shines with a steady yellowish glow in the south. A small telescope will reveal its spectacular rings beautifully on display for us this year since they are tilted in our direction. Saturn will be with us most of the summer just to the right of the constellation Scorpius, the scorpion.
In July we have two full moons, on July 1 and then again on July 31, a phenomenon sometimes known as a Blue Moon.
If you can stay up late enough to see any stars, check out the Summer Triangle, a large configuration of three bright stars high in the east. Bright white Vega stands at the top of the triangle with Deneb to the lower north and Altair to the lower south. Below and to the left of Saturn, Antares, the heart of the scorpion, glows red-orange low in the south. Just west of overhead, Arcturus, another orange star, shines very brightly. Southwest of Arcturus, look for the star Spica in the constellation Virgo, the virgin.
One hot place
With the days and the nights so short, the celestial body that catches our attention this time of year is our own personal star, the sun. Do not ever look at it, not even a glance — it is far too bright for our sensitive eyes.
All that light and heat is generated deep inside the sun by a process called nuclear fusion. The intense pressure at the core of our star slams two tiny hydrogen atoms together to make one helium atom. Six hundred million tons of hydrogen are converted to helium in the sun every second. A small portion of that hydrogen is turned into pure energy, causing the sun to lose weight at the rate of over 4 million tons every second. If this sounds alarming and you are worried that the sun might disappear right before your eyes, remember that the sun weighs a hefty 2 octillion tons. That is a 2 followed by 27 zeros. It has plenty of gas left to keep us warm for quite a while longer.
One curious by-product of the nuclear fusion going on within our sun is the creation of lots of neutrinos, tiny sub-atomic particles that fly at us through space traveling at the speed of light. It is estimated that 20 trillion of these ghost-like particles zoom through each of our heads every second, and I bet you never even noticed!
The July sun can feel very intense shining down on you while you are enjoying all the outdoor activities we like in the summer. Here is an interesting fact to contemplate on these warm days. Our own neighborhood star produces and emits the equivalent energy of 6 trillion Hiroshima- sized nuclear bombs every second. Be sure to put on plenty of sunscreen!
There is a good reason that there just does not seem to be enough night to see the stars this time of year. On June 21 in Winthrop, astronomical twilight — when the sky gets really dark — ended at 12:30 a.m. Then it starts to get light again at 1:34 a.m. That only gives us one hour and four minutes of real darkness at night. No wonder it is so hard to see the stars up there now!
On July 6, Earth reaches that point in its orbit known as aphelion, our farthest distance from the sun. Why is it so darn hot these days? Because the northern hemisphere where we live is tilted towards the sun, but I am sure you knew that!