The Hubble telescope has shown us countless billions of galaxies in areas of the universe which we once thought were empty. For example, by focusing on a small speck in the sky in an area that was thought to be void of stars, astronomers soon discovered that this small speck actually contained 1,500 galaxies! And remember that each galaxy can contain untold millions of stars and some astronomers now believe that there may be as many galaxies in the sky as there are stars in our own galaxy.
In an effort to learn more about space, mankind has put men on the moon and brought them back home safely, built a space station where astronauts can stay for months at a time. But space travel carries some great risks, and is quite costly. And these adventures of man into space are merely flying hundreds of miles into the sky—they come nowhere close to probing the true depths of space!
After reaching the moon, astronomy’s next goal is to put a man on Mars—a planet in our solar system about 150 million miles from Earth (compare to the moon at only 240,000 miles away). Even if this journey is successful, the trip of 150 million miles is a mere jog compared to the vastness of space. We might intrude into space, but we as humans cannot even begin to conquer it. Getting to Mars is only one planet of a vast solar system, part of an even larger galaxy—one of trillions of galaxies in this huge universe which are billions of light years away from Earth.
Light travels at over 186,000 miles per second; a light year is how far light can travel in a year moving at 186,000 miles per second, which figures out to be close to 6 trillion miles. (To travel just one light year at 100 miles per hour, it would take almost 7 million years.) Another measurement astronomers use is an au (astronomical unit). An au is the distance between the Earth and the sun—about 93 million miles.
The Giant Milky Way
All the space vehicles, manned or unmanned, still travel within our one galaxy—the Milky Way—one of millions or billions of galaxies. The Milky Way is considered a giant galaxy and contains about 400 billion stars. It is a spiral galaxy, which means that from a distance it looks like a pinwheel, or a big disc in the center with flat arms going out in all directions.
To get an idea of how vast this galaxy is, to travel the distance from the outer end of one disc to the outer end of another would take 100,000 years traveling at the speed of light.
Located on one of these discs—which is rotating around the center of the galaxy—is our solar system: the sun, moon, Earth and the planets. The star of our solar system, the sun, is located about two thirds of the way out from the center of the galaxy—roughly 28,000 light years from the center. Whereas it takes the Earth one year to orbit the sun, it takes the sun 250 million years to make just one orbit of the center of the galaxy.
Unmanned Spaced Probes
Voyagers 1 and 2 were launched in 1977 to explore where nothing from Earth had ever been before. Now they each are much farther from Earth than any space vehicle has ever been. Speeding outward at more than 38,000 miles per hour, both continue to send back scientific information about their surroundings through the Deep Space program.
Voyager 1 remains operational, currently pursuing its extended mission to locate and study the boundaries of the Solar System, including the Kuiper belt and beyond. Its original mission was to visit Jupiter and Saturn; and it was the first probe to provide detailed images of the moons of these planets.
“Voyager 1 is currently the farthest human-made object from Earth, and as of August 28, 2009, it is about 110.94 AU (16.596 billion km, or 10.312 billion miles) from the Sun, and has passed the termination shock, entering the heliosheath, with the current goal of reaching and studying the heliopause, which is the known boundary of the solar system. If Voyager 1 is still functioning when it finally completes the passage through the heliopause (effectively becoming the first human-made object to leave the solar system), scientists will get their first direct measurements of the conditions in the interstellar medium. Its primary targets were the planets Jupiter and Saturn and their associated moons and rings; its mission was the detection of the heliopause and particle measurements of solar wind and the interstellar medium. Both of the Voyager probes have far outlasted their originally-planned lifespan. Each probe gets its electrical power from three radioisotope thermoelectric generators (RTGs), which are expected to continue to generate enough electric power to let the probes keep communicating with Earth at least until the year 2025.” (Wikipedia)
By that time, Voyager 1 will be more than 12.4 billion miles from the sun. In some 296,000 years, if Voyager 2 was still traveling, it would pass Sirius, the brightest star in our sky, at a distance of about 4.3 light years (25 trillion miles).
Even more amazing were the Pioneer projects. Pioneers 10 and 11 were launched in 1972 and 1973—the fastest man-made objects to leave the Earth, launched at the incredible speed of 32,000 miles per hour. That is fast enough to pass the moon in 11 hours, and Mars’s orbit (50 million miles away) in just 12 weeks.
“Pioneer 10 (also called Pioneer F) was the first spacecraft to travel through the asteroid belt, which it entered on July 15, 1972, and to make direct observations of Jupiter, which it passed by on December 3, 1973. By some definitions, Pioneer 10 has become the first artificial object to leave the solar system. It is the first human-built object to have been set upon a trajectory leading out of the solar system. However, it still has not passed the heliopause or Oort cloud. The last weak signal from Pioneer 10 was received on January 23, 2003, when it was 12 billion kilometers (7.5 billion miles) from Earth. It is now heading in the direction of the star Aldebaran (about 68 light years away) in the constellation Taurus at roughly 2.6 AU per year. It will take Pioneer 10 over 2 million years to reach it. (Wikipedia)
Pioneer 11 was to go on after passing Jupiter 400 million miles away. Using this giant planet as a sling shot, Pioneer 11’s speed now reached 108,000 miles per hour. By 1979, Pioneer 11 flew within 13,000 miles of Saturn. In November 1995 the last communication from Pioneer 11 was received, as the Earth’s motion carried Saturn out of the view of the spacecraft antenna. Pioneer 11 is now headed toward the constellation of Aquila, just northwest of the constellation of Sagittarius and may pass near one of the stars in the constellation in about 4 million years.
We can barely begin to imagine how vast our universe is by how vast our own galaxy is! Manned and unmanned spacecraft can barely cover any significant ground in the area called “space.” Despite the incredible speeds of some of these vehicles, they are still millions of years away from the closest stars. The more we venture out into space, the more the immenseness of it staggers our imagination. That’s why I find it amusing when scientists make definitive statements about something that is so hard to comprehend. It’s better to keep the attitude humble, allow God to reveal truth to us and realize on our own, we really don’t know what we are talking about.