Mars Makes History - Closest To Earth Aug 27
http://img117.imageshack.us/img117/6674/hfscituearthmars0826017cb.jpg
As if executing a cosmic air kiss, Earth and Mars will come as close as they desire in the wee hours of Wednesday during an historical event that has captivated the attention of skywatchers around the globe.
The two planets will be separated by 34,646,418 miles (55,758,006 kilometers) at 5:51 a.m. ET (1051 GMT) on Aug. 27.
Not since the Neanderthals shared this planet with early humans have the two worlds been so close.
The span of space is small only in the cosmic sense, however. Despite rumors, there will be no chance of collision and no unusual or dangerous gravitational effects. It is just a wonderful opportunity for anyone to enjoy a slice of astronomical history and to see Mars as bright as it can be.
Public interest in the event has soared recently as media around the world cover the story, which was first reported by SPACE.com last November.
"It's taken on almost a mystical importance with people," said Ray Villard, news director at the Space Telescope Science Institute, which operates the Hubble Space Telescope.
Hubble, which orbits Earth, will take advantage of the proximity by snapping two pictures of Mars for release Wednesday. The first will be available on SPACE.com shortly after 6 a.m. ET (1100 GMT) that day.
Mars rises in the southeast around sunset, your local time, shimmering like an orange star so bright it could momentarily be mistaken for an airliner on final approach. It outshines all other stars in the sky. Around 1 a.m. Mars is due south and high in the sky. It sets in the southwest at about sunrise.
How to watch
No equipment is necessary to observe Mars closer than has any human in the past 59,619 years. But the best views are afforded through telescopes, which can reveal surface markings, the south polar ice cap and clouds. For this purpose, astronomers recommend at least a 70mm lens for so-called refractor telescopes, or 4.25 inches for the reflector type.
However, telescopes are in short supply at many stores, as a sort of Mars mania has folks scurrying to buy optical aids.
People in many communities will flock to local observatories and amateur astronomy outings for a chance to peek through really big telescopes. Web searches can yield contact information for local astronomy clubs, and the Planetary Society has created an extensive list of related events.
Everyone has potential ringside seats to this celestial wonder. Mars is visible to anyone on Earth with clear skies. And the exact instant of the closest approach is relatively unimportant, other than marking a curious mathematical moment.
In fact, many people will not see Mars at 5:51 a.m. ET (1051 GMT) on Wednesday. It will have sunk nearly to the southwestern horizon for residents of eastern North
America, and it will be broad daylight then in Europe and other parts of the world. Weather could ruin the view for some hopeful observers.
Mars, though, is essentially the same brightness any night or early morning now through Sept. 2, and it will remain a delightful skywatcher's target into October.
What's going on
The unusually close approach -- less than 1 percent closer than a similar event in 1971 -- is created by a confluence of orbital oddities.
Earth and Mars are like cars on a racetrack, with Earth on the inside. Every 26 months or so, Mars is at opposition -- directly opposite the Sun in relation to Earth, just as Earth "laps" Mars in the never-ending race. Mars reaches opposition this week, causing it to rise around sunset and set at sunrise.
As with any opposition of Mars, this one offers a shorter path for spacecraft, and four of them are bound for the red planet right now. NASA has two probes en route, slated to land and deploy rovers in January. Another lander was shot to Mars by the European Space Agency, and the Japanese have a Mars orbiter on the way.
For skywatchers, this opposition is particularly special.
The orbits of both planets are not quite circles. So every 15 years, a Mars opposition comes when the red planet is about as near to the Sun as its orbit ever carries it (a point called perihelion) and Earth is near its outermost point (called aphelion).
Further, the two orbits actually rotate in space, bringing Earth's aphelion and Mars' perihelion to even greater proximity at certain times -- like this week.
Imagine each orbit being shaped a bit like the outline of a football (the oblong, American variety). A smaller football is rotating freely inside a larger one. Every now and then -- as measured in cosmic time -- the pointy end of the inner football is lined up with the laces of the outer football.
With all these factors involved, the timing of the closest approach rarely if ever coincides with the moment of opposition, but they're usually within a few days of each other. Mars achieves opposition the day after this year's close approach.
There is yet another factor at work.
"Mars has been slowly getting closer to the Sun at the perihelion point of its orbit (that part of the orbit closest to the Sun)," explains Joe Rao, SPACE.com's Night Sky columnist.
Rao, who has been scrutinizing this year's close approach since last year, says this change in Mars' orbit has probably contributed to a bunching of similar events over the past few centuries.
In fact, an even closer pass is on the horizon, at least for a future generation of skywatchers. In 2287, Mars will be slightly nearer to Earth than it is this week.
Source: www.space.com
http://img117.imageshack.us/img117/6674/hfscituearthmars0826017cb.jpg
As if executing a cosmic air kiss, Earth and Mars will come as close as they desire in the wee hours of Wednesday during an historical event that has captivated the attention of skywatchers around the globe.
The two planets will be separated by 34,646,418 miles (55,758,006 kilometers) at 5:51 a.m. ET (1051 GMT) on Aug. 27.
Not since the Neanderthals shared this planet with early humans have the two worlds been so close.
The span of space is small only in the cosmic sense, however. Despite rumors, there will be no chance of collision and no unusual or dangerous gravitational effects. It is just a wonderful opportunity for anyone to enjoy a slice of astronomical history and to see Mars as bright as it can be.
Public interest in the event has soared recently as media around the world cover the story, which was first reported by SPACE.com last November.
"It's taken on almost a mystical importance with people," said Ray Villard, news director at the Space Telescope Science Institute, which operates the Hubble Space Telescope.
Hubble, which orbits Earth, will take advantage of the proximity by snapping two pictures of Mars for release Wednesday. The first will be available on SPACE.com shortly after 6 a.m. ET (1100 GMT) that day.
Mars rises in the southeast around sunset, your local time, shimmering like an orange star so bright it could momentarily be mistaken for an airliner on final approach. It outshines all other stars in the sky. Around 1 a.m. Mars is due south and high in the sky. It sets in the southwest at about sunrise.
How to watch
No equipment is necessary to observe Mars closer than has any human in the past 59,619 years. But the best views are afforded through telescopes, which can reveal surface markings, the south polar ice cap and clouds. For this purpose, astronomers recommend at least a 70mm lens for so-called refractor telescopes, or 4.25 inches for the reflector type.
However, telescopes are in short supply at many stores, as a sort of Mars mania has folks scurrying to buy optical aids.
People in many communities will flock to local observatories and amateur astronomy outings for a chance to peek through really big telescopes. Web searches can yield contact information for local astronomy clubs, and the Planetary Society has created an extensive list of related events.
Everyone has potential ringside seats to this celestial wonder. Mars is visible to anyone on Earth with clear skies. And the exact instant of the closest approach is relatively unimportant, other than marking a curious mathematical moment.
In fact, many people will not see Mars at 5:51 a.m. ET (1051 GMT) on Wednesday. It will have sunk nearly to the southwestern horizon for residents of eastern North
America, and it will be broad daylight then in Europe and other parts of the world. Weather could ruin the view for some hopeful observers.
Mars, though, is essentially the same brightness any night or early morning now through Sept. 2, and it will remain a delightful skywatcher's target into October.
What's going on
The unusually close approach -- less than 1 percent closer than a similar event in 1971 -- is created by a confluence of orbital oddities.
Earth and Mars are like cars on a racetrack, with Earth on the inside. Every 26 months or so, Mars is at opposition -- directly opposite the Sun in relation to Earth, just as Earth "laps" Mars in the never-ending race. Mars reaches opposition this week, causing it to rise around sunset and set at sunrise.
As with any opposition of Mars, this one offers a shorter path for spacecraft, and four of them are bound for the red planet right now. NASA has two probes en route, slated to land and deploy rovers in January. Another lander was shot to Mars by the European Space Agency, and the Japanese have a Mars orbiter on the way.
For skywatchers, this opposition is particularly special.
The orbits of both planets are not quite circles. So every 15 years, a Mars opposition comes when the red planet is about as near to the Sun as its orbit ever carries it (a point called perihelion) and Earth is near its outermost point (called aphelion).
Further, the two orbits actually rotate in space, bringing Earth's aphelion and Mars' perihelion to even greater proximity at certain times -- like this week.
Imagine each orbit being shaped a bit like the outline of a football (the oblong, American variety). A smaller football is rotating freely inside a larger one. Every now and then -- as measured in cosmic time -- the pointy end of the inner football is lined up with the laces of the outer football.
With all these factors involved, the timing of the closest approach rarely if ever coincides with the moment of opposition, but they're usually within a few days of each other. Mars achieves opposition the day after this year's close approach.
There is yet another factor at work.
"Mars has been slowly getting closer to the Sun at the perihelion point of its orbit (that part of the orbit closest to the Sun)," explains Joe Rao, SPACE.com's Night Sky columnist.
Rao, who has been scrutinizing this year's close approach since last year, says this change in Mars' orbit has probably contributed to a bunching of similar events over the past few centuries.
In fact, an even closer pass is on the horizon, at least for a future generation of skywatchers. In 2287, Mars will be slightly nearer to Earth than it is this week.
Source: www.space.com
