13 August 2016

THE AGE OF ASTRONOMY. 1/7 Instruments: NASA's spacecraft STEREO. Predicting the Sun's activities. 2006AD

Ancient Astronomy Series: THE AGE OF ASTRONOMY. 1/7 Instruments: NASA's spacecraft STEREO. Predicting the Sun's activities. 2006AD

What is the age of Astronomy? How old is it? Can we find some tangible evidence of it's age?
Many clues can be found in almost all civilizations on Earth before us.
In this mini series of articles we will establish the chronology of astronomy with astronomical relics, instruments, artifacts, alignments, maps, references and places in ancient periods pinpointing exactly in time, the age of Astronomy.

Ancient Astronomy Series. List of articles:
    1/7 Instruments: NASA's STEREO mission. Predicting the Sun's activities. 2006AD
    2/7 : Relics: Abù Bakr Ibn Yùsuf's medieval Moroccan astrolabes. 1216AD
    3/7: Places: El caracol, Mayan Observatory. 906AD
    4/7: Artefacts: Nebra sky disk of North Germany. 1600BC
    5/7: Astronomical References: The scarab and the Dung beetle. 1813BC
    6/7: Alignments: Megaliths of Carnac, France. 3300BC
    7/7: Maps: Prehistoric Starmap. 10500BC

Illustration 1: stereo_01 NASA/Johns Hopkins University Applied Physics Laboratory -

2006 AD. NASA's STEREO mission. Predicting the Sun's activities.
Location: Space.
The STEREO missions are fairly new in terms of astronomy methods. It is what we call space astronomy, not based on Earth, but in space. The STEREO satellites are what we investigate in this article. Our current civilization is the only known civilization that has used space based observatories (telescopes and satellites). We all know that astronomy was not invented in this century, but I wanted to start somewhere. If someone would have been born yesterday, he or she would have proof that astronomy existed from only 2006AD onward.
So here we have tangible evidence of astronomy.

STEREO (Solar Terrestrial Relations Observatory) is a solar observation mission. Two nearly identical spacecraft were launched in 2006 into orbits around the Sun that cause them to respectively pull farther ahead of and fall gradually behind the Earth. These satellites sent into space had to travel ahead or behind the Earth to position them self for the task they were ask to perform.
This enables stereoscopic imaging of the Sun and solar phenomena, such as coronal mass ejections.

Illustration 2: stereo_02 Since its launch in 2006, the STEREO spacecraft have drifted further and further apart to gain different views of the sun. Credit: NASA/GSFC

The two STEREO spacecraft were launched on October 26, 2006 into highly elliptical geocentric orbits. The apogee reached the Moon's orbit. On December 15, 2006, on the fifth orbit, the pair swung by the Moon for a gravitational slingshot. Because the two spacecraft were in slightly different orbits, the "ahead" (A) spacecraft was ejected to a heliocentric orbit inside Earth's orbit while the "behind" (B) spacecraft remained temporarily in a high Earth orbit. Spacecraft A will take 347 days to complete one revolution of the Sun and Spacecraft B will take 387 days. The A spacecraft/sun/earth angle will increase at 21.650 degree/year. The B spacecraft/sun/earth angle will change −21.999 degrees per year. Over time, the STEREO spacecraft will continue to separate from each other at a combined rate of approximately 44 degrees per year. There are no final positions for the spacecraft. They achieved 90 degrees separation on January 24, 2009, a condition known as quadrature. On February 6, 2011, the two spacecraft were exactly 180 degrees apart from each other, allowing the entire Sun to be seen at once for the first time.

Even as the angle increases, the addition of an Earth-based view, e.g. from the Solar Dynamics Observatory, will still provide full-Sun observations for several years. In 2015, contact will be lost for several months when the STEREO spacecraft pass behind the Sun. They will then start to approach Earth again, with closest approach sometime in 2023. They will not be recaptured into Earth orbit.

The principal benefit of the mission is stereoscopic images of the Sun. In other words, because the satellites are at different points along the Earth's orbit from the Earth itself, they can photograph parts of the Sun that are not visible from the Earth.

These crafts flown to space are obviously of a new era in astronomy, the space era. It gives to astronomy a new dimension. It is clear that these STEREO satellites are tangible evidence of knowledge of astronomy.

So what is the age of Astronomy, you ask? In a hypothetically scenario where i would not know nothing about astronomy, my knowledge of astronomy would only be of 9 years from 2006AD (as this article was written in 2015). So, we could say that with only the knowledge of the STEREO mission as an astronomical reference and proof, i would think that astronomy is only 9 years old. Of course everybody knows about astronomy, but let's pretend...
So what is the age of Astronomy, you ask? The knowledge of astronomy is at least 9 years old.
The search for the age of Astronomy is still out there. 

Read the next article of our series on The age of Astronomy and see how far back we can push it's age in time. Stay tuned, and continue reading Ancient Astronomy Series: THE AGE OF ASTRONOMY. 

Next Article: THE AGE OF ASTRONOMY. 2/7: Relics: Abù Bakr Ibn Yùsuf's medieval Moroccan astrolabes 1216AD.

Illustration 3: By NASA - NASA, Public Domain,

Please take time to read the links and PDF files on this subject.

Pubic outreach program  by Astronomy club Toutatis, Kustavi, Finland

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