Solar sailing

Solar sails have been long-discussed as a way to propel spacecraft.  The sails exploit the fact that solar wind exerts pressure on a mirrored surface.   This can be used for propulsion in a way that is akin to sails used by sailboats.

LightSail® is a solar sail project from the Planetary Society that has championed solar sailing for decades. The Society’s LightSail-2 spacecraft, launched 25 June 2019, is the first spacecraft in Earth’s orbit propelled solely by sunlight. On 31 July 2019, the LightSail-2’s orbit was raised, showing that solar sailing is a viable means of propulsion for CubeSats—small, standardised spacecraft that are part of a global effort to lower the cost of space exploration.

 The image above shows LightSail-2's sail after its deployment.

Most Popular Posts

As you know on the first day of the new year, I publish the all-time favorites.   This year the top three from the 190 posts were:

1.    In the Land of the Cyclops

http://dgscrosscountrychronicles.blogspot.com/2016/04/in-land-of-cyclops.html

2.   Poseidon’s Temple and the Aegean Sea

http://dgscrosscountrychronicles.blogspot.com/2014/04/poseidons-temple-and-aegean-sea.html

3.   Porto Rafti

http://dgscrosscountrychronicles.blogspot.com/2014/03/porto-rafti.html

Most of the 50,000+ visitors were from the United States, followed by Greece and Russia, France, Germany, Ukraine, Ireland, Canada, United Kingdom and Australia.

I wish you all and your loved ones a healthy and happy New Year.  I also hope 2020 will bring peace on home planet Earth.

Hayabusa heading home

Japan's Hayabusa-2 spacecraft has departed from the asteroid Ryugu with samples of its soil and begun its year-long journey back to Earth. 

Hayabusa-2 was launched in 2014. Three and a half years later, it reached the asteroid Ryugu, located about 300 million km (190 million miles) from Earth.  The spacecraft is expected to return to Earth in December 2020, dropping a capsule containing the rock samples in the South Australian desert.  

Following its arrival in June 2018, the spacecraft made touchdowns twice, collecting data and rock samples from the Ryugu - a primitive space rock leftover from the early days of the Solar System

Scientists believed these would be more pristine samples, since they would not have been exposed to the harsh environment of space. They were the first underground samples collected from an asteroid in space history.

While asteroids are some of the oldest objects in space, Ryugu belongs to a particularly primitive type of space rock, and may contain clues about the conditions and chemistry of the early days of the Solar System - some 4.5 billion years ago.

The last two races of 2019

Porto Rafti’s nautical club Ν.Α.Σ.Π.Ο.Ρ organizes several sailboat races during the summer every year with the last two crossing to the second largest of the Greek Islands, Eboia (Εὔβοια,) or Evia.  Eboea derives its name from the words εὖ "good", and βοῦς "ox", meaning "the land of the well-fed oxen.  An interesting vignette is that the philosopher Aristotle died on the island of Eboea in 322 BC. 

The race on September 29, 2019 was to the coastal town of Karystos in the south coast of Evia. In antiquity Karystos’ name was Chaeronea and was famous for its wealth.

The medieval Castello Roso overlooks Karystos.  The impressive Venetian castle was built in the 13^th century, and is offering a panoramic view of the town.  

The overall winner of the race to Karystos was the legendary Okyrhoe.  In the picture we see the boat maneuvering near the starting line with my brother Nikos at the helm. 

The last race was to little port of Marmari in the southeast coast of Evia.  The boats are jockeying at the starting line.  

In this picture we see the southwest coast of Evia and the nearby Petali islets.  These two races concluded the 2019 season.  It is time for the boats and the sailors to rest and prepare for the 2020 season.  I wish you all a good winter, stay healthy and get ready for 2020! 

Achilles Island

The dying Achilles (Αχιλλεας θνησκων), a marble statue in the grounds of Achillion Palace, in the island of Kerkyra, raises the question to where Achilles the bravest of all Greeks was buried after he was killed in the Trojan War.  

In this Attic lekythos c. 510 BC we see Ajax carrying the body of Achilles.  It is exhibited at Staatliche Antikensammlungen in Munich. 

Although there are many sites claiming to be Achilles’ tomb, we have a credible story by Captain Kritzikly, who in 1824 visited the island of Leuke and discovered the ruins of a temple in which a wooden statue of Achilles was found.  Captain Kritzikly drew a map of the temple and described his findings in detail. 

In 1840s the island was visited again.  Unfortunately a lighthouse was built in the same spot and resulted in the complete destruction of the temple and the surrounding structures. (Image from Wikiwands)

The experts agree that there were many temples dedicated to Achilles on Leuke in the 6^th century BC.  Did the construction many temples on Leuke meant to honor Achilles or was it because he was buried in one of them?  Nobody knows as Achilles and Ajax likely were buried near Troy as Nestor tells Telemachus “so many battles round King Pram’s walls we fought, so many gone, our bravest and best fell.  There Ajax lies, there Achilles too, the greatest man of war. (Homer’s Odyssey Book Three 119-122), and this is why the “seabirds dip their wings in the water to sweep the temples clean”.  

Epic Journeys

In Ernest Shackleton’s epic journey to the Antarctica after their boat Endurance was trapped, he and five of his crew set sail on a 22-foot boat from Elephant island to South Georgia 800 miles away. Alfred Lansing in his novel Endurance p 278 writes that the sea is a different kind of enemy.  Unlike the land, where courage and the simple will can often see a man, through, the struggle against the sea is an act of physical combat, and there is no escape.  It is a battle against a tireless enemy in which man never actually wins; the most he can hope for is not to be defeated.  Their struggle to survive became a testament of the human spirit and how much adversity humans can endure.

We did our sailboat crossing from Spain to Greece, one hundred years after Shackleton's epic voyage.  Although we use the word Epic when we refer to our journey it was in the Mediterranean a benign Sea comparing to South Atlantic.  We battled storms after we left the strait of Bonifacio heading south in the Tyrrhenian Sea and later in the Ionian Sea. Because of my fellow mariners' skill and tenacity against the elements we were able to complete our crossing in the summer of 2015. 

The Ultimate Journey

Although black holes have been studied for decades, all the images you’ve ever seen of them have been computer simulations or artist’s conceptions, until now.

On April 10, 2019, astronomers unveiled the first photo of a black hole, which is 6.5 billion times more massive than our sun. It is located in the center of the galaxy M87, 55 million light-years from Earth. The image shows a bright ring caused by superheated gas falling into the hole as the light bends in the intense gravity around the hole.

To obtain the image, astronomers used the Event Horizon Telescope, an idea that first Prof Falcke suggested, that links eight ground based telescopes around the globe to form an Earth-sized virtual telescope. Its Earth-sized scale gives it sensitivity and resolution that’s truly unparalleled. 

Black holes have raised complex questions about the nature of space and time and therefore "their existence is making astronomers ecstatic, as they were able to see the unseeable and the one-way portal to eternity", Dr. Doeleman, a lead scientist said.  This is a remarkable accomplishment of the human species thus the term Homo Sapiens is well deserved.

It is my hope that future generations continue channeling their energies and intelligence in projects like this for the good of all species on our planet and out of respect for the cosmos.

We are in awe by the progress in science illustrated here and seen in many other scientific endeavors. When I posted this, I learned about the passing of George Paulson, a highly respected physician and renowned researcher, historian and devoted family man. A man of good will who was always helpful to his patients and fellow men. We all share his dream that progress in the sciences and medicine will reduce the suffering from disease. We also hope that the advances in science will be accompanied by progress in our society to provide for the ill and disadvantaged. I consider this as Dr. Paulson’s legacy.