Science World

Rare Astronomical Event Occurs Tuesday in US

This June 8, 2004 file photo shows the transit of Venus, which occurs when the planet Venus passes between the Earth and the Sun, is pictured in Hong Kong. (AP Photo/Vincent Yu,File)

This June 8, 2004 photo shows the transit of Venus, which occurs when the planet Venus passes between the Earth and the sun, pictured in Hong Kong. (AP Photo/Vincent Yu,File)

On Tuesday,  June 5, people in most parts of the world have a good chance of witnessing a once-in-a-lifetime astronomical event called the transit of Venus.

It’s a planetary alignment which occurs when the planet Venus passes directly between the Earth and sun.

For those of us here on Earth, it’ll look like a little black dot beginning on the edge of the sun and gliding across the face of it over a couple of hours.

The transit of Venus is expected to occur at around 2209 UTC.  Of course,  clouds could obscure the view and people in Portugal, southern Spain, western Africa, and the portions of South America are unlikely to see the occurrence because that part of the world will be in total darkness the entire time of the transit.

The striking event occurs about once a century, in pairs, with around eight years separating each twin event.  This upcoming occurrence is the second in a recent pair of events, the first of which took place in 2004.

Tomorrow’s transit will mark only the seventh time the phenomenon has been seen since it was first observed in 1639 by Jeremiah Horrocks and William Crabtree of England.

In 1627, astronomer Johannes Kepler became the first person to successfully forecast a transit of Venus when he predicted the 1631 event.

According to NASA, the 18th century astronomer, Edmund Halley – of Halley’s Comet fame – came up with a way of using the transit of Venus to determine the distance between Earth and the sun. He suggested  measuring the start and end times of the transit from different points on Earth, using methods of triangulation to make the calculation.

The method was first tried in 1761, but the international team’s efforts were unsuccessful due to poor weather and other factors.

If you want to watch the transit of Venus be sure to take precautionary measures.  These people, for example are using solar viewing glasses to safely view the Sun. (Photo: NASA)

If you want to watch the transit of Venus be sure to take precautionary measures. These people, for example are using solar viewing glasses to safely view the Sun. (Photo: NASA)

Another effort, in 1769,  with observation points all over the world, proved more successful, providing statistical data that led scientists to calculate the mean distance from the Earth to the sun was around 150,838,824 kilometers. Using more modern, technologically-advanced equipment, scientists now say the mean distance from the Earth to sun is 149,600,000 kilometers. Seems that, with Sir Edmund Halley’s help, the 18th century calculations were pretty darn close.

Speaking of NASA, the space agency announced that Don Pettit, a flight engineer on the International Space Station, will photograph the event. It’s the first time the transit of Venus has been observed from space.  The astronauts aboard the ISS in 2004 weren’t able to see the transit because they didn’t have any solar filters which would allow them to safely observe it.

Observatories and other various science-oriented institutions from around the world will be opening their doors to host transit watching parties and events.

World map show visibility of transit of Venus on June 5-6, 2012. (Map: Michael Zeiler)

World map show visibility of transit of Venus on June 5-6, 2012. (Map: Michael Zeiler)

If you’re planning on watching the transit of Venus, please make sure to take precautions, since looking at the sun directly can cause serious damage to your eyes.  Experts recommend you use protective glasses or telescope lenses with special solar filters, or better yet, watch it on TV or the Web.  Good luck with your observations because the next set of transits won’t take place until 105 years from now, in 2117.

 

Needle-free Blood Test Is on the Way

Young woman expresses her aversion to getting jabbed with a needle as a medical technician draws blood (Photo: US Navy)

Young woman gets jabbed with a needle as a medical technician draws blood (Photo: US Navy)

A new device uses light instead of needles to test blood.

Researchers in Israel are developing the pain-free test, which is expected to reveal similar information as traditional blood tests, providing the doctor with immediate results.

Besides providing the patient with a relatively stress-free experience, the optical unit,  which is no bigger than a breadbox, can also provide high-resolution images of blood flowing through our veins without the need for the harsh and short-lasting fluorescent dyes that are used in some test procedures.

“We have invented a new optical microscope that can see individual blood cells as they flow inside our body,” says Lior Golan, a graduate student at the Israel Institute of Technology, who co-authored an article in the Optical Society‘s journal Biomedical Optics Express.

While similar devices can “see” blood-flow, Golan says his team’s invention combines features which allow doctors to focus in on single cells, helping to provide additional information such as the shape and size of each cell, as well as other crucial diagnostic statistics.

An in vivo image shows red blood cells within a microvessel. (Photo: Biomedical Optics Express)

An in vivo image shows red blood cells within a microvessel. (Photo: Biomedical Optics Express)

Other units are also far less practical, according to Golan,  because they rely on bulky equipment and use potentially-harmful fluorescent dyes that must be introduced into the patient’s bloodstream.

The new microscope is based on a modest optical element and is driven by a technique called spectrally encoded confocal microscopy (SECM), which creates images by splitting a light beam into its basic colors -red, yellow, orange, green, cyan, blue, and violet- and emits them in a line of multi-colored light.

That rainbow-like light line is then focused across an appropriate blood vessel near the surface of the patient’s skin, and as flowing blood cells cross over the line it scatters the light.

The colors produced by the scattered light provide information which is interpreted by the system’s computer programs creating 2-D images of the blood cells.

The team’s device relies on a technique called spectrally encoded confocal microscopy. (Photo: Biomedical Optics Express)

The team’s device relies on a technique called spectrally encoded confocal microscopy.  (a) A single line within a blood vessel is imaged with multiple colors of light that encode lateral positions. (b) A single cell crossing the spectral line produces a two-dimensional image. (Photo: Biomedical Optics Express)

To use the device now, a doctor first attaches a small probe to the patient’s lower lip, with the patient’s blood vessels displayed on a nearby monitor.

After selecting a suitable vessel to help align and set the microscope, the doctor could begin to observe and analyze individual blood cells.

In the future, Golan says that his team is planning to miniaturize this device down to the size of a hand-held probe, devising a system that would automatically analyze the images, providing the doctor with valuable parameters and statistics to diagnose the patient.

Lior Golan joins us on this week’s radio edition of “Science World” to talk about how the device could one day become one your doctor’s most important diagnostic tools.  Check out the right column for scheduled air-times or listen to the interview with Mr. Golan below.

[audio://blogs.voanews.com/science-world/files/2012/06/One-On-One-Lior-Golan-Needle-less-Blood-Tests.mp3|titles=One On One – Lior Golan – Needle-less Blood Tests]

Other stories we cover on the “Science World” radio program this week include: