The Sun Today
The Sun Today
Astronomy Picture of the Day
Picture of the Day
McMath Pierce Solar Telescope
Solar Telescopes
Flux Emergence
Sunspot Formation

Sydney D'Silva

Biked 1291 miles in 2009. Hiked 653 miles in 2010 and 596 in 2012.
Sydney D'Silva
Biking
My Specialized Tricross hybrid has taken me over nearly all bike trails of Northern Virginia and DC. One of my best is the Rock Creek Park trail in DC. This is about a 30-40 mile round trip from . I started tracing my path on the Every Trail site using my Google phone and the Every Trail app. The Every Trail site uses Actionscript and renders the trail in Flash. I thought it would be better to have it using JavaScript because currently (as of July 2009) Flash has not yet come to iPhones, though Adobe had announced that it was in the making. So I wrote my own JavaScript by putting together the GoogleMaps API and Jquery. Here you will see my biking trails overlapped on Google maps.

See the latest trails at http://sdsilva.org/trails/biking

Virginia Trails
  1. Commuter Page
  2. Martha Custis Trail
    • 4 miles of asphalt trail joins the Mt. Vernon trail to the W&OD trail
  3. W&OD Trail
    • 45 miles from Shirlington to Purcellville (asphalt)
    • WABA link
    • Map
  4. Four Mile Run Trail
  5. Mt. Vernon Trail
    • 18.5 miles from Rosslyn to Mt. Vernon (asphalt)
    • WABA link
    • Map
  6. Fairfax County Trails
  7. Fairfax Cross County Trail
    • 40 miles of mixed trail from Potomac river at Great Falls Park to Occoquan river in Occoquan regional park
    • Map
  8. Shenandoah National Park
    • 105 miles of Skyline drive. Share the road with cars.
Maryland Trails
  1. Maryland Trails on American Trails
  2. The Great Alleghany Passage
    • 150-miles from Cumberland, MD to Pittsburgh, PA
    • Western Maryland Rail Trail
    • 21 miles of paved trail
    • To reach the eastern end of the Western Maryland Rail Trail, take exit 12, MD 56, from I-70. Turn east and go to Big Pool. The trail parking lot is across the street from the Post Office.
    • DNR link
  3. Washington and Baltimore Rail Trails
  4. Washington, Baltimore and Annapolis Trail
  5. Baltimore - Annapolis Trail
    • 13 miles of Asphalt
  6. Capital Crescent Trail
  7. C&O Canal
  8. The Northern Central & York County Heritage Trails
    • 41 miles of crushed gravel
  9. Rock Creek Trail
    • 41 miles of asphalt
    • Map
  10. BWI Trail
    • 12.5 miles of asphalt
  11. Anacostia Tributary Trail System
  12. Metropolitan Branch Trail
Washington,DC Trails
  1. DDOT Bicycle Map
    A downloadable pdf map of the DC area bike trails from the District Department of Transportation.
If you want to see your GPS trails overlayed on Google maps, upload it here:
For more flexibility create a username/password :
Hiking
We hiked a total of 653 miles in 2010.

See the latest trails at http://sdsilva.org/trails/hiking

If you want to see your GPS trails overlayed on Google maps, upload it here:
For more flexibility create a username/password :


Publications in Solar Physics and Biology.




Time-distance helioseismology is a method to study the interior of the Sun by computing travel time of individual acoustic wavepackets as they travel through the Sun between two spatially separated locations on its surface. I have contributed to the theoretical development of this field.
eg.  Theoretical Foundations of Time-Distance Helioseismology


Helioseismic tomography is a form of the tomographic techniques adapted to image the interior of the Sun from observations of the acoustic oscillations at the surface. The important adaptation is the computation of travel time through time-distance helioseismology. I have contributed in the aspects of its adaptation and improvement.
eg.  A Note on Helioseismic Tomography


This study involves the dynamics of their progenitors -- magnetic flux tubes --- from the region
of their origin (200,000 km beneath the solar surface) through a highly turbulent convectively unstable region. We modeled the flux tube to be a one-dimensional string with all properties of a magnetic flux tube allowed to move in the three-dimensional space of the convection zone. We could successfully explain a number of dynamical and morphological properties of sunspots if the magnetic field strength of the flux tubes at the region of their origin were of the order of 100,000 G. This is order of magnitude larger than the field that would be in energy equipartition with the turbulent motions.
A Theoretical Model for Tilts of Bipolar Magnetic Regions
My Experiments in Photography
Smithsonian Museum of Natural History
Birds Mammals Fishes Herps Entomology
email: sdsilva@comcast.net
Ph: (703) 346-7306
Schedule PHY220
Text: Explorations: An Introduction to Astronomy
Thomas T. Arny
Ecuador's Rain Forest

More slideshows are coming soon...

The Rain Forest

Quito, Ecuador

Trails are coming soon...

Warning: These are full resolution images and very slow to download!

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