Jared May: What's Up, August 12-19

What’s Up This Third Week of August

It will be rainy and cloudy leading up to the weekend, but Saturday and Sunday may have some partially clear nights for us stargazers. The weekdays following may also be plagued by cloudy skies.

On the few clear nights coming up, the temperature will be in the mid-sixties, which is perfect for stargazers and amateur astronomers alike.

Sunset this week is around 8:30 PM, so be ready with your telescopes and binoculars by 9:30 PM. This week be on the lookout for fireballs of the Perseid meteor shower, the first quarter moon, a Mercury-Mars, meetup, and play a game with the first stars to shine after sunset. I will also include a short section on what the scientific data suggests about the ultimate fate of the universe.

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Almost everywhere online ,and almost every news network, has mentioned the Perseid meteor shower at some point this past week. This meteor shower is arguably the most famous of the year – it is during a warm time of the year, it produces up to 100 meteors per hour, and the meteors are pretty bright! The peak was technically during the very early morning of August 12, however, there are still huge numbers of fireballs that can be seen over the next few days. These shooting stars that you see will likely appear to originate from a part of the sky near the famous Cassiopeia constellation- that “w” shape in the northeast sky. This falling space dust burns up in the atmosphere just 50 miles above your head as it slams into Earth’s atmosphere at roughly 37 miles per second!

The location of the radiant (the place from which the meteors appear to emanate) of the Perseid meteor shower is, as the name suggests, in the constellation Perseus, just below the famous “W” of Cassiopeia in the northeast sky. Meteors, however, can appear all over the sky and will do so well into the weekend.

The moon is getting brighter over the next several days. It will be finishing off its waxing crescent phase and achieving its first quarter phase this Sunday, August 15. This weekend, during the potentially clear nights, will be a great time to view the moon under the magnification of a telescope or binoculars. The dark gray and ancient lava seas will be visible, the contrasty craters will be easy to spot, and just after sunset, you may be able to see “earthshine” where the unlit side of the moon stands out against the sunset skies.

The “first quarter” moon, appears a week after new moon.

If you have a stargazing spot with a clear western horizon, you will be able to spot Mercury approaching Mars heading into Wednesday, August 18. This will be a tricky observation to make, considering these two planets are so low to the horizon this time of year and the sky will still be bright from the recently set sun.

As you prepare to stargaze, the time of greatest anticipation is between sunset and all the stars becoming visible against the darkening night sky. After the sun sets, it just becomes a waiting game. You can play “I spy” with different stars. After the sun sets, the first “star” you will see is Venus, which hangs low in the western skies and closely follows the sun. Soon after, start looking for Vega and Arcturus which hang almost directly over your head. These two stars will eventually become the brightest in the night sky as it continues to get darker. Then Altair and Deneb will become visible, and the Summer Triangle will be complete. Try not to get Saturn or Jupiter confused with one of these stars as they will be hanging out in the eastern skies. Lastly, look for Polaris, the North Star. By this point, you can start running your telescope’s alignment process and stargazing can begin. (IMAGE)

If skies are very clear, Mercury and Mars might be seen in heavy twilight a half hour after sunset.

In last week’s blog, I shared how the future of the universe may be a cold, empty, and dark. I want to now talk about some of the physics and data that govern this outcome. First, we must understand some terminology and background.

The space inside our universe on the large scale is expanding and the state of the universe is described as being flat, open, or closed, or in other words, “steady” expansion, accelerating expansion, and slowing expansion. The state of the universe is dictated, we think, by the ratio of “normal gravity” (like gravity produced by the earth, sun, galaxy, dark matter, etc.) to “non-normal gravity” (like dark energy that may be driving the expansion of the universe). Recent measurements performed by several ground- and space-based telescopes have revealed that the universe is flat to within 0.4% error. In other words, our universe once showed signs of slowing expansion but now shows signs of continuous expansion into that dark and cold universe I talked about last week.

The state of the universe is still a highly researched and debated field, but the implications are not yet fully understood, and may never be fully understood by our feeble human minds.

http://www.astro.sunysb.edu/rosalba/ast101/LECT22.pdf

A graph showing the possible fate of the universe given constant expansion, expansion that is slowing down (due to gravity alone) and expansion that is speeding up due to some as-yet not understood force which has been given the name “dark energy”. This last fate seems the most likely outcome.

Hopefully, the weather is nice to us stargazers and amateur astronomers this weekend. Enjoy the warm summer skies this weekend while you look for the fireballs of the Perseids under the first quarter moon. If the clouds are forgiving, look for Mars and Venus while you play “I spy” with the first stars of the night. Clear Skies!