Back in the 1900s, astronomers realized they had a big problem if they were going to hold onto the notion that the solar system was billions of years old. The problem was the simple comet, a ball of ice and rock streaking between parts unknown and the sun. People have long seen comets as being omens of things to come. In fact, the Bible states that the sun, moon and stars will be used for signs and seasons. (Gen 1:14) Now comets are certainly not stars, but they do appear to be to someone without binoculars or telescopes. The big question is where do they come from? This weekend, the comet Siding Spring passed by the planet Mars necessitating the movement of several probes from possible danger. Astronomers speculate that comets, particularly “long-period” ones come from the theorized Oort Cloud. The Oort Cloud was first theorized in 1932 by Ernst Opic. Jan Oort popularized the idea in the early fifties, speculating that there were billions of comets in this cloud. To date, in spite of the advances in astronomy, we still have not see any evidence of the Oort Cloud. Without the Oort Cloud, the solar system cannot be billions of years old. With the Oort Cloud, the solar system could still be 6000 years old.
Once in a million year comet ‘Siding Spring’ will pass close to Mars on Sunday and NASA has the best seats in the house
- Comet is traveling at 126,000 mph and will pass the Red Planet on Sunday
- NASA is diverting its three Martian satellites and two rovers onto the ball of ice
PUBLISHED: 14:32 EST, 16 October 2014 | UPDATED: 05:35 EST, 17 October 2014
The heavens are hosting an event this weekend that occurs once in a million years or so. (The heavens are hosting this, to be sure, and they truly declare the glory of God.)
A comet as hefty as a small mountain will pass mind-bogglingly close to Mars on Sunday, approaching within 87,000 miles at a speed of 126,000 mph.
NASA’s five robotic explorers at Mars — three orbiters and two rovers — are being repurposed to witness a comet named Siding Spring make its first known visit to the inner solar system. So are a European and an Indian spacecraft circling the red planet.
The orbiting craft will attempt to observe the incoming iceball, then hide behind Mars for protection from potentially dangerous dusty debris in the comet tail.
Shielded by the Martian atmosphere, the Opportunity and Curiosity rovers may well have the best seats in the house, although a dust storm on Mars could obscure the view.
‘We certainly have fingers crossed for the first images of a comet from the surface of another world,’ said NASA program scientist Kelly Fast. (This is one of the coolest things I can think of for astronomers and man.)
Spacecraft farther afield, including the Hubble Space Telescope, already are keeping a sharp lookout, as are ground observatories and research balloons.
‘We’re getting ready for a spectacular set of observations,’ said Jim Green, head of NASA’s planetary science division.
Named for the Australian observatory used to detect it in January 2013, Siding Spring will approach Mars from beneath and zoom right in front Sunday afternoon, Eastern Time.
On Earth, the best viewing, via binoculars or telescope, will be from the Southern Hemisphere — South Africa and Australia will be in prime position. In the Northern Hemisphere, it will be difficult to see Siding Spring slide by Mars.
The comet — with a nucleus estimated to be at least a half-mile in diameter — hails from the Oort Cloud on the extreme fringe of the solar system. It formed during the first million or two years of the solar system’s birth 4.6 billion years ago and, until now, ventured no closer to the sun than perhaps the orbits of Jupiter, Saturn, Uranus or Neptune. It comes around every one or more million years. (The Oort Cloud is simply a theorized area assumed to be anywhere from 2,000 to 100,000AU. (Some estimates are as far as 200,000AU.) An AU is the distance from the sun to Earth – 93 million miles. This is a huge area and could not be reasonably expected to ever reveal itself with current or even future technologies. As a result, astronomers have simply taken to saying the Oort Cloud exists. For the solar system to be 4.6 billion years old, there would have to be a holding area for comet-like bodies. There would also have to be a mechanism for “kicking” the comets out of the Oort Cloud. Astronomers theorize that this could happen becasuse of gravitational forces from nearby passing stars. The closest star to us is Alpha Centauri, a 3-star cluster over 4 light years away. A light year is approximately 63,000AUs, so 4 light years is approximately 250,000AUs. To put that into perspective, the closest star, Alpha Centauri, could be closer to the Oort cloud than our sun! And gravity would pull the comet, not push it. The Alpha Centauri star cluster also has over twice the mass of our sun, and therefore twice the pull. But I believe the real problem for objects at such great distances is that the attraction between the two objects is far too small to have any significant effect. In other words, a body 93,000,000,000,000 miles from the sun is not going to be affected enough to eventually make the trek to the inner solar system. One last thing, please note how the writer – and astronomers as well – take as a given that the Earth is 4.6 billion years old, in spite of the obvious problems with the stardard naturalistic theories.)
It will be the first Oort Cloud comet to be studied up close in detail.
For comparison, the flyby distance of 87,000 miles is about one-third of the way from here to the moon. Siding Spring’s tail could extend from Earth all the way to our moon. Its gaseous coma, the fuzzy head surrounding the nucleus, might stretch halfway to the moon.
No comet has come anywhere near this close to Earth in recorded history.
‘We can’t get to an Oort Cloud comet with our current rockets … so this comet is coming to us,’ said Carey Lisse, senior astrophysicist at Johns Hopkins University’s applied physics laboratory.
By studying Siding Spring’s composition and structure, scientists hope to learn more about how the planets formed, according to Lisse. Scientists also are keen to spot any changes to the comet or Mars due to the close approach. NASA’s newly arrived Maven spacecraft, for instance, will compare the upper atmosphere before and after it passes.
‘Think about a comet that started its travel probably at the dawn of man and it’s just coming in close now,’ Lisse said. ‘And the reason we can actually observe it is because we have built satellites and rovers. We’ve now got outposts around Mars.’ (This statement demonstrates just how little we know about comets. We cannot track short or long period comets to determine what their paths will be for the next orbit. Halley’s famed comet is predicted to come every 76 years. However, one orbit took an extra year and a half due to a tug on it by Jupiter. It has taken about 80 orbits if we calculate based on 76 years and 6000 years. Since comets eject a percentage of their mass every close pass to the sun. This is why astronomers need the Oort Cloud – they need somewhere for comets like Halley and Siding Spring to magically pop out of in order for the solar system to be billions of years old.)
Scientists initially worried the spacecraft orbiting Mars would be at considerable risk from the comet’s massive trail of dust.
The nucleus itself poses no danger of impact. But the particles in the tail, hurtling through space at 126,000 mph could fry electronics, puncture fuel lines, or destroy computers, transmitters or other vital spacecraft parts.
As Siding Spring’s path became clearer, the threat level was deemed minimal. Still, space agencies are taking no chances. They’re employing the ‘duck and cover’ strategy.
NASA’s three orbiters — Mars Odyssey, Mars Reconnaissance Orbiter and newcomer Maven — will be behind the red planet at the time of peak danger. That’s a 20-minute-or-so period approximately 1½ hours after the closest approach by the comet’s nucleus.
The European Space Agency also shifted the orbit of its Mars Express as did India for its Mars Orbiter Mission, or MOM, the country’s first interplanetary spacecraft that, like NASA’s Maven, arrived last month.
The precautions are prudent, said University of Maryland senior research scientist Tony Farnham, who led a hazard-analysis team.
‘Comets are complex beasts and don’t always live up to our predictions,’ Farnham said in an email Wednesday. ‘If you don’t want surprises, then don’t study comets.’
It will take at least a few days to obtain and analyze the best spacecraft data; but images made from Earth should be forthcoming pretty quickly.
Siding Spring should pass closest to the sun six days after its Mars flyby, then swing back out, bidding goodbye, for at least another million years.