ScienceIQ.com

Why Is Blood Pressure Two Numbers?

Blood pressure might better be called heart pressure, for the heart's pumping action creates it. To measure blood pressure, health workers determine how hard the blood is pushing at two different times: when the heart contracts, called systole; and when the heart relaxes, called diastole. The contraction of the ventricles during systole gives the ...

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WhyIsBloodPressureTwoNumbers
Astronomy

The Chandra Mission

NASA's Chandra X-ray Observatory, which was launched and deployed by Space Shuttle Columbia on July 23, 1999, is the most sophisticated X-ray observatory built to date. Chandra is designed to observe ... Continue reading

Chandra
Geology

Salty Remnants At Death Valley's Badwater

Beneath the dark shadows of the Black Mountains, a great, extraordinarily flat expanse of shimmering white spreads out before you. You are at Badwater, at -282 feet it is the lowest spot in the ... Continue reading

SaltyRemnantsAtDeathValley
Biology

What Gives Hair Its Color?

Put a single hair under a microscope, and you'll see granules of black, brown, yellow, or red pigment. What you are seeing are tiny particles of melanin, the same pigment that gives skin its color. ... Continue reading

WhatGivesHairItsColor
Medicine

When and Why is Blood Typing Done?

Fans of the popular television show ER know how important blood type is in an emergency. 'Start the O-neg,' shouts Doctor Green, and the team swings into action. Green calls for type O, Rh-negative ... Continue reading

BloodTypes

Voyager Phone Home

VoyagerAfter historic visits to Jupiter and Saturn, Voyager 1 is now on course to be the first human-made object to leave our solar system. In space for more than 25 years, it has already traveled farther than any other spacecraft. It is not clear when Voyager 1 will reach the heliopause boundary, where the influence of our Sun ends. The boundary is thought to exist somewhere from 8 to 22.5 billion kilometers (5 to 14 billion miles) from the Sun. When Voyager 1 does cross over, scientists will be able to measure the interstellar environment without the influence of the Sun for the first time.

Voyager 1 is speeding along at about 57,600 kph (35,790 mph) - fast enough to travel from the Earth to the Sun three and a half times in one year. As of March 2002, Voyager 1 was at a distance of 12.4 billion kilometers (84 Astronomical Units) from the Sun. But it could still take more than 20 years to escape our solar system. Its sister spacecraft, Voyager 2, will be the next object out of our solar system. Pioneer 10 and Pioneer 11 also are on courses that will eventually take them into interstellar space.

All four spacecraft are carrying messages from humanity. Both Voyagers carry a gold record 'greeting to the universe' containing sounds and images selected to portray the diversity of life and culture on Earth.