Tag Archives: Space

Student controlled satellite sensors

I’ve been hearing about a number of interesting science/tech education projects recently, all approaching the topic in innovative and very hands-on ways. Just recently I met someone working for a new startup called Ardusat, which provides students with the opportunity to program and operate Arduino microcontrollers aboard satellites. These microcontrollers are connected to a variety of sensors, allowing students to design experiments and collect a variety of data. Here we are, barely 50 years after the launch of Sputnik, and space has become a laboratory accessible from the classroom. 

100,000 Stars

100,000 Stars is an online visualization of our solar system’s nearest neighboring stars. It was created by Google’s Data Arts Team (see a write-up of the project here). Although it is perhaps a bit difficult to extract specific useful information from this site, it provides an interesting perspective on our place in the universe, a self-portrait of our galaxy (or at least some subset of it) that could only be possible with a computer visualization.

The planets that once were

The solar system is our home, our own comfortable little neighborhood of the galaxy, and as mankind has grown as a species and become more technologically capable, we have begun to venture forth into this neighborhood and to familiarize ourselves with it. The results are far more wondrous and varied than we could have imagined when all we knew of the cosmos was what we could see with our eyes only.

The planets that have been known of since antiquity are those that are easily visible with the naked eye – Mercury, Venus, Mars, Jupiter, and Saturn. Even before we knew of these things as astrophysical objects, they were seen as bright points of light that seemed to wander independently of the background of the stars. In the 1700s and 1800s the solar system became populated with more than just these familiar few, and as these discoveries were made it became clear that it was a more diverse place than we had suspected. As Uranus (1781) and Neptune (1846) were discovered, it was clear that these objects were of the same nature, albeit a little farther and a little dimmer. But the objects Ceres (1801) and Pluto (1930) were not so clearly determined.

Pluto and Ceres share common ground in that they both have introduced us to regions of our solar system populated by hundreds of thousands of objects: the asteroid belt in the case of Ceres, and the Kuiper belt in the case of Pluto. With these discoveries came the need to further consider the nature of these objects and the proper ways to categorize them. Ceres and Pluto trailblazed the identification of asteroids and dwarf planets, but for all the discussion they have introduced, we’ve never really gotten a good look at either one. Two recent missions have set out to correct this deficit and make us a little bit more familiar with some of the Earth’s diminutive cousins.

A size comparison of different solar system bodies. [http://www.spacewallpapershd.com/wp-content/uploads/2015/03/more_planet_size_comparisons_wallpaper_free.png]

On January 1st, 1801, Giuseppe Piazzi discovered a new object orbiting at about 2.8 AU from the sun. Although it was difficult at first to ascertain the exact size of this object, dubbed Ceres, it was clear that it was not quite in the same category as the known planets. Therefore, the term ‘asteroid’ (‘star-like’) was coined. Nevertheless, some textbooks listed Ceres as a planet among the others, and continued to do so for a number of decades.

Soon after Ceres became known astronomers found other objects to populate the region of space between Mars and Jupiter, a region that has since become known as the asteroid belt. Ceres is often referred to as an asteroid, although the new designation ‘dwarf planet’ also applies.

On March 6th, 2015, the Dawn spacecraft (http://dawn.jpl.nasa.gov/) arrived at Ceres. As it approached the asteroid, it was able to achieve stunning photos of this object, revealing a pock-marked face reminiscent of the lunar surface. Dawn continues to explore the surface and atmosphere of Ceres, revealing to us information about the formation and evolution of the solar system.

Images of Ceres as taken by the Hubble Space Telescope. [http://en.wikipedia.org/wiki/File:Ceres_Rotation.jpg]

Images of Ceres as taken by the Dawn mission on its approach to the asteroid. [http://photojournal.jpl.nasa.gov/catalog/PIA19183]

The discovery of Pluto, which took place in 1930, is much more recent, and has proved to be a bit more controversial. Many people are familiar with the discussion that took place a few years ago that resulted in the re-categorization of Pluto as a dwarf planet. Some took this hard, and consider this more of a demotion than a categorization. For the entirety of the twentieth century after its discovery, Pluto was considered the ninth planet. It was only as other objects began to be discovered in the same region of space, now referred to as the Kuiper belt, that the call for reclassification came.

The deciding moment came in 2005 when the object Eris was discovered and found to be roughly the same size as Pluto, though orbiting at a greater distance. Rather than considering Eris the tenth planet, and opening the way for some as yet unknown number of similar objects to become planets, the International Astronomical Union (IAU) decided to meet and formally consider the definition of ‘planet’. They settled on the following three properties:

  1. It must be in orbit around the sun.
  2. It must be massive enough for its gravity to pull it into an approximately spherical shape.
  3. It must have “cleared its neighborhood” of similarly sized objects and become the gravitationally dominant body.

Objects that meet the first of these two requirements, such as Pluto and Ceres, but fail the third are categorized as dwarf planets.

On July 14, 2015, the New Horizons spacecraft (http://www.nasa.gov/mission_pages/newhorizons/main/) is expected to arrive at Pluto, achieving a fly-by distance of about 10,000 km. Due to the distance between the Earth and Pluto, it will have taken New Horizons over 9 years to reach its destination. When it arrives, it will be able to take images superior to those possible from Earth with even the most powerful telescopes.

Pluto and its moon Charon, as seen by the Hubble Space Telescope. [http://nssdc.gsfc.nasa.gov/photo_gallery/photogallery-pluto.html]

For all the discussion of categorization, in the end, names are just names. A dwarf planet, by any other name, would orbit just as sweet, to butcher Shakespeare. Categorizations are a useful tool to help us understand Nature and its workings, but there will likely always be natural phenomena that defy these classifications, no matter carefully we define them. The important matter is not what we call something, but what new insights into the universe it has to offer.

Wanderers

Wanderers

Wanderers, a short film from digital artist Erik Wernquist, is an amazing visual exploration of what the future may hold for the human race. Wernquist provides digital reconstructions of what various places in the solar system might look like as they are explored and settled by people, and it’s all overlaid with the voice of Carl Sagan. It’s quite beautiful.

I am reminded of a quote from Joseph Conrad’s Heart of Darkness, in which the protagonist imagines what it would be like to have approached our own home planet as someplace new:

“We were wanderers on a prehistoric earth, on an earth that wore the aspect of an unknown planet.”

The Overview Effect

Once a photograph of the Earth, taken from outside, is available… a new idea as powerful as any in history will be let loose.

Starting with this quote from astrophysicist Fred Hoyle, the film OVERVIEW explores the changes in perspective that arrived with manned space flights and accompanying images that showed, for the first time in human history, the tenuous piece of real estate on which we all reside. When viewed from this vantage point, the Earth exists as a complete and unified whole, virtually free of any arbitrary divisions created by humankind. It also appears fragile and alone, something that needs to be fought for, cherished, and protected.

It’s a brilliant and beautiful film. It may be the most wonderful thing I’ve seen so far this year.

The continuing mission of Voyager

One of the most interesting outcomes of the space exploration push in the 60s and 70s was the Voyager program. In August 1977, Voyager 2 was launched on a mission to explore the solar system, followed shortly in September by Voyager 1 (yes, Voyager 2 was launched first, but it travels slower than 1, and has been surpassed). They’ve accomplished a lot, but as Paul Gilster notes at Centauri Dreams, they’re not yet done.

Voyager 1 completed its study of the solar system in 1980 and began its interstellar mission. Voyager 2 achieved this in 1989. At the moment, almost 36 years after their launch, the spacecraft are far out there (but not quite yet out of the solar system, depending on your definition). They’re still sending back scientific information, from such a large distance that it takes light from the Sun over 12 hours to reach them (out to Pluto takes about 5.5 hours). This makes them the farthest man-made objects ever sent out from Earth.

Their scientific missions virtually over, the spacecraft have adopted a new role as artifacts of human civilization, time capsules of everything we were when we launched them. In addition to the craft themselves, which have plenty of meaning (some thoughts on that from Matthew Battle), each of the Voyagers carries on it a Golden Record, a snapshot of our world, a collection of nature images and sounds, snippets of music from a variety of different cultures, greetings in 55 different languages.

planet montage

 

But space is immense. It will be 40000 years before Voyager 1 comes close to any other planetary system, and even then it will still be 1.6 light years away. There is virtually zero chance that these records will ever reach anything intelligent enough to decode and understand them. In all likelihood they will drift alone through the darkness of interstellar space for far longer than human civilization will be around. So why did we go through the trouble of making them and sending them out? This supposedly futile act has more to do with mankind than with any attempt to contact an extraterrestrial species. In Carl Sagan’s words, 

The spacecraft will be encountered and the record played only if there are advanced space-faring civilizations in interstellar space. But the launching of this bottle into the cosmic ocean says something very hopeful about life on this planet.

Much of the space race had to do with cross-cultural competition, nationalistic displays of military and technological prowess. The Voyager Records are an attempt to acknowledge to ourselves our own impermanence, to rally around the messages of hope and goodwill. Gilster sums it up well,

I think any future archaeologist, human or otherwise, would read into the Voyager spacecraft the desire of a species to transcend itself, hopeful of finding a bridge to other intelligence but pressing on regardless as a way of building meaning into the cosmos.