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Dark matter bothers me. It also bothers scientists.

Galaxies don’t rotate by the same physics that we know and understand. Scientists noticed that stars at a galaxy’s edge rotate faster than expected. How can we explain that? There must be matter that is invisible to us that is there.

In 1998 and the Hubble Space Telescope observations of a very distant supernovae showed that a long time ago the universe was actually expanding more slowly than it is today. We once believed that gravity was causing the slowing expansion of the universe, but this showed that it was accelerating.

expansion of universe

A diagram reveals showing the rate of expansion since the universe’s birth 15 billion years ago. The curve changes noticeably about 7.5 billion years ago, when objects in the universe began flying apart at a faster rate. Astronomers theorize that the faster expansion rate is due to a mysterious, dark force that is pulling galaxies apart. Credit: NASA/STSci/Ann Feild

Astronomers know more about what dark matter is not than what it actually is. Roughly 68% of the universe is dark energy. Dark matter makes up about 27%. The rest is, well, everything on Earth. This “normal matter” is less than 5% of the universe. Actually, that hardly makes it qualify as the”norm.”

Most of the universe is made up of dark energy, and that mysterious force drives the accelerating expansion of the universe. The next largest ingredient is dark matter, and that only interacts with the rest of the universe through its gravity.

At one time, the theory was that MACHOs (Massive Compact Halo Objects) was the cause.  A MACHO, such as a brown dwarf, would be so massive that it would bend light around them. We know they exist, and we know they are out there, even though they are too dark for us to see. But this theory fell out of favor because there are not enough of them to make the galaxy-rotation math work.

Astrophysicists next came up with the WIMP (Weakly Interacting Massive Particles – the scientists do have a sense of humor). Maybe the universe is full of very small things we can’t see.

And maybe dark matter is made up of a different object we have never observed. One candidate is the neutralino.

We keep looking. The Large Hadron Collider, one of the most expensive science experiments ever built, is looking, but hasn’t found them.

But we do know that the universe is “heavier” than what we can see.

There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
– Hamlet (1.5.167-8)

Dark matter doesn’t keep me up at night. But it did bother Alvy in the film Annie Hall.

Have a mooncake this weekend.

The Autumn Equinox occurs every year between September 21 and 24. On the two equinoxes every year the Sun shines directly on the Equator and the length of day and night is nearly equal – but not exactly. Then, our planet tilt away from the Northern Hemisphere.

Today is the day for 2018 that the Sun will cross the celestial equator. That is the imaginary line in the sky above the Earth’s equator from north to south. And we in the Northern Hemisphere will enter autumn.

We don’t celebrate the equinox as formally as it was celebrated in ancient times.  Most of our ways of marking the day come from our European ancestors. In Britain, they marked autumn on the Sunday closest to the Harvest Moon. The Harvest Moon is the Full Moon closest to autumnal equinox. This year that will be the Full Moon on Tuesday the 25th, so be a Brit and celebrate this Sunday.

During the French Revolution, the fall equinox marked the start of a new calendar year.

Japanese Buddhists celebrate Higan during both the Spring and Autumnal Equinox. The tradition came from celebrating the mild weather that usually occurs during the time of the equinoxes.

In China, the celebration also occurs with the Harvest Moon rather than the day of the equinox and the harvest of rice and wheat. Family celebrations also include lanterns and special foods including mooncakes.

Your autumn tradition may include apple picking, a hayride, raking leaves, apple cider donuts and, of course, pumpkin spice everything.

Venus and Earth size comparison

Tonight and Friday night are when Venus will be at its brightest. When we see the planet’s daytime/illuminated side is when it is bright and right now is when we see the maximum amount of it.

Venus is the third-brightest celestial body in Earth’s sky (after the Sun and Moon) and is often mistaken for a star.  Tonight you would see it low in the sky with Jupiter, Saturn and Mars above it in a fairly straight line.

When Venus passes between the Earth and Sun (October 26), it will leave the evening sky and move into our morning sky. That passing is known to astronomers as an inferior conjunction of Venus, after which its day side is facing away from us.

I love the stories of the Pioneer and Voyager spacecraft taking their messages from Earth out into universe. Humanity’s farthest and longest-lived spacecraft, Voyager 1 and 2, achieve 40 years of operation and exploration this August and September. Despite their vast distance, they continue to communicate with NASA daily, still probing the final frontier.

Both Pioneers carry a plaque, but the Voyager spacecrafts carry a “phonograph record.” But I have always wondered what an alien finding it would be able to figure out about us. A lot of thought was given to what was included, but could it be understood? How might it be misunderstood?

Just on the basis of technology, if the Voyager’s “Golden Record” dropped into your backyard, could you “play” it? Chances are that you don’t even have the equipment to play a vinyl record any more.

Of course, we always seem to imagine the aliens as being way more advanced than us, so they could figure it out, right?

Besides a turntable and speakers, this record requires the aliens to have ways to hear and see similar to the ways we do those things. A lot of science-fiction tales have not shown us aliens with our ears and eyes. Can they interpret the record by just using their mind?

The Voyager record has a cover illustration and about 90 minutes of audio on the reverse side.

Looking at the cover illustration image of hydrogen and a pulsar map (the same as found on the Pioneer plaques) and important instructions on how to play them. It tells the aliens how to use the included stylus and what rate of rotation the record must be used and the proper waveform of signals generated by the record. These are similar instructions to those we would need to give to a Generation Z kid confronted with a record player.

Let’s assume they get the record to play and they have ears to hear it. What will they think about us when listening to the 50+ greeting messages in different languages? Again, I think of a Gen Z or almost any Earthling hearing 50+ different messages in different languages. Confusion. They might wonder why we don’t all speak in the same way. Or maybe they think all 50 messages are in the same language but are just different creatures speaking.

Then there is the music. I can’t imagine how they would react to hearing Chuck Berry’s “Johnny B. Goode.” Are these dancing aliens?  I would guess that they might deal better with the Beethoven and Stravinsky without lyrics, though it is doubtful that music developed in the same way out there in the universe.

The record also contains 115 images. If they can decode the first ones, they will have technical data for the reader regarding mathematical definitions, scales and sizes, and information about our location and how to find us. There are images of our Sun and some of the planets in our solar system. Some pretty famous scientists have said that we really shouldn’t be telling them that because we don’t want them to find us.. These scientists are believers in the “aliens are evil” school of thought.

The images seem to me to be the part they might understand. Didn’t they tell me in elementary school that math was a universal language?

Will they interpret the medical and scientific diagrams showing the structure of our DNA and detailed images of human anatomy?

I do think they will be confused by some of the others in this Earthing photo album:  people eating, looking through a microscope, on a spacewalk, a string quartet etc. I am actually a bit frightened by how they might interpret a picture of a woman licking an ice cream cone.

Voyager 1 is currently in “Interstellar space” and Voyager 2 is currently in the “Heliosheath” (the outermost layer of the heliosphere).

Though the Moon will be “fullest” in Paradelle at 01:56:12 pm today, I will (like most of us) be looking up at it tonight.

One neo-pagan name for this August Full Moon is the Lightning Moon, and around Paradelle there has been a lot of thunder, lightning and rain.

This August Full Moon is also known as the Sturgeon Moon, since that large fish of the Great Lakes and other major bodies of water were most readily caught during this month. It may be called the Red Moon because, as the Moon rises, it appears reddish through any sultry haze.

The video visualization that tops this post tries to capture the mood of Claude Debussy’s “Clair de Lune” (moonlight in French) from 1905 with images from NASA of the Moon built from the Lunar Reconnaissance Orbiter. “Clair de Lune” is the third of four movements in his Suite Bergamasque, but this section is quiet, contemplative, and melancholy. It feels right for solitary gazing at the Moon, full or not, inside or outside.

Maybe you can combine the video and music with one of these relaxation techniques tonight and ease yourself into a gentler new week ahead.

The peak of the Perseid meteor shower this year was probably this morning and the morning of August 13 – so you have another chance to see these meteors.

The moon is missing from the night sky and that darkness may bring peaks of 50 or more meteors per hour. Find the darkest sky near you late at night as you can. Even being in the shadow of a tree or building to block lights will help you spot a “shooting star.”

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