|
Korean Job Discussion Forums "The Internet's Meeting Place for ESL/EFL Teachers from Around the World!"
|
View previous topic :: View next topic |
Author |
Message |
mithridates

Joined: 03 Mar 2003 Location: President's office, Korean Space Agency
|
Posted: Mon Oct 31, 2005 4:37 pm Post subject: Pluto has three moons, not one |
|
|
Weird!
Quote: |
Two More Moons Discovered Orbiting Pluto
By Robert Roy Britt
Senior Science Writer
posted: 31 October 2005
01:01 pm ET
Two small moons have been discovered orbiting Pluto, bringing the planet's retinue of known satellites to three and leaving scientist to wonder how it could be.
The newfound moons orbit about 27,000 miles (44,000 kilometers) from Pluto, more than twice as far as Charon, Pluto's other satellite. They are 5,000 times dimmer than Charon.
Preliminary observations suggest they are in circular orbits around Pluto and in the same plane as Charon, said Hal Weaver of the Johns Hopkins Applied Physics Laboratory.
"That suggests they probably formed at the same time as Charon," Weaver told SPACE.com in a telephone interview Friday. NASA planned a teleconference with reporters Monday at 1 p.m. ET to announce the discovery.
While scientists had predicted there might be more moons, the newfound setup is surprising nonetheless, in part because Pluto is smaller than our own Moon.
"It's almost like a mini solar system," Weaver said. "How can something about 70 percent the size of Earth's Moon have all these satellites? How can that happen? We're going to have to explain that."
The leading theory for the formation of Charon involves a large object striking Pluto. The debris from that collision could have formed the two smaller moons, Weaver speculates. It can't be ruled out that they might have been captured into the system, but that seems very unlikely, he said.
The two new moons are between 30 and 100 miles (45 to 160 kilometers) in diameter, Weaver said. There is not enough data to pin their size down exactly, however. Pluto is 1,430 miles wide and Charon's diameter is about 730 miles.
The moons were found using the Hubble Space Telescope.
Piece of the puzzle
The discovery represents one more piece of an increasingly complex puzzle in the outer solar system, a place that astronomers look to for clues in understanding how it all formed 4.5 billion years ago in the wake of the Sun's birth.
Lately, so many objects have been found in so many configurations out there, that astronomers can't even agree on what to call them.
Though popularly considered a planet, Pluto is now viewed by most astronomers to be a member of the Kuiper Belt, a vast sea of frozen worlds beyond Neptune that hadn't been discovered when Pluto was found 75 years ago. The region includes other round objectswith moons, and one recently discovered world is larger than Pluto.
For now, Pluto is the only Kuiper Belt object known to have more than one companion.
"Our result suggests that other bodies in the Kuiper Belt may have more than one moon as well," said team co-leader Alan Stern of the Southwest Research Institute in Boulder, Colo.
Stern heads up the New Horizons mission to Pluto and the Kuiper Belt, slated for launch early next year. He had long predicted other moons around Pluto.
There could be more moons to find, too, but they would be small.
"These Hubble images represent the most sensitive search yet for objects around Pluto," said team member Andrew Steffl of the Southwest Research Institute, "and it is unlikely that there are any other moons larger than about 10
miles across in the Pluto system."
Easy to find
The moon-hunting project was denied by Hubble planners several times and took years to get approved, and only then after a failed instrument on Hubble last year caused project leaders to add several previously unaccepted observing programs to fill the schedule.
For Hubble, this one was easy.
Unlike many observing projects that require several Hubble orbits – often 15 or more and sometimes many dozens -- Weaver's team needed just two orbits. On the first set of observations they spotted the two points of light, then on the second orbit they found them again and made sure they moved against the background of relatively fixed stars.
The presumed moons are 23rd magnitude, far to dim to be seen with a typical backyard telescope but "relatively easy to see with Hubble," Weaver said.
Then the astronomers dug up old Hubble observations done by colleague Marc Buie of the Lowell Observatory, to see if the same objects had been imaged before.
Weaver said they are pretty sure they've located the moons in the archived photos, and the combination of data is what suggests the moons' circular orbits in the plane of Charon's path.
More Hubble observations are planned for February to confirm the discoveries and pin down the orbits.
The moons are catalogued as S/2005 P1 and S/2005 P2 for now. Once they are confirmed, the discoverers will suggest names, to be approved by the International Astronomical Union. |
|
|
Back to top |
|
 |
rapier
Joined: 16 Feb 2003
|
Posted: Mon Oct 31, 2005 8:12 pm Post subject: |
|
|
What is the purpose of space exploration mith?
It seems a brutal waste of time and money. Is it an act of vanity on the part of developed western nations who will boast "we have pictures of some far off inhospitable planet, we put a man on the moon".
is it to discover an inhabitable planet for us to escape to as we destroy our own?
Is it for wonderment, entertainment?
is it to try and learn some lessons from the cosmos to better enable us to live on earth? if so, I think we have all we need here already, infinitely more wondrous life all around us, in extraordinary complexity. No need to look at billions of lifeless stars.
So..many new planets and moons have been discovered? Yawn....I just don't see the purpose of it all. with respect... whats the attraction, whats the point exactly? |
|
Back to top |
|
 |
Wrench
Joined: 07 Apr 2005
|
Posted: Mon Oct 31, 2005 8:56 pm Post subject: |
|
|
seeing beyond our own little area is always good. Plus there is a lot of information that can be aquired by looking at the stars. |
|
Back to top |
|
 |
mithridates

Joined: 03 Mar 2003 Location: President's office, Korean Space Agency
|
Posted: Mon Oct 31, 2005 11:52 pm Post subject: |
|
|
R, are you serious? I've talked about the subject many times before, but the 8 to 1 return on investment into space technology is all you need to know. IOW, every $1 invested into NASA brings $8 in benefits to a nation's people.
Case #1: you're from Africa. Lots of Malaria there. Good weather satellites can predict when and where rain is going to fall so that you can take out mosquitoes before they breed. Otherwise you're going to just be spraying willy-nilly and wasting money. That in itself is worth the money.
If you want a few dozen other examples I have them, or you can check yourself. |
|
Back to top |
|
 |
mithridates

Joined: 03 Mar 2003 Location: President's office, Korean Space Agency
|
Posted: Mon Oct 31, 2005 11:55 pm Post subject: |
|
|
And sorry if I'm curt; I'm in a bit of a hurry. But investment into space technology is definitely worth the money. However, it should be done mostly by private companies. |
|
Back to top |
|
 |
Manner of Speaking

Joined: 09 Jan 2003
|
Posted: Tue Nov 01, 2005 3:55 am Post subject: |
|
|
mithridates wrote: |
R, are you serious? I've talked about the subject many times before, but the 8 to 1 return on investment into space technology is all you need to know. IOW, every $1 invested into NASA brings $8 in benefits to a nation's people.
Case #1: you're from Africa. Lots of Malaria there. Good weather satellites can predict when and where rain is going to fall so that you can take out mosquitoes before they breed. Otherwise you're going to just be spraying willy-nilly and wasting money. That in itself is worth the money.
If you want a few dozen other examples I have them, or you can check yourself. |
And along those same lines, the more that is known about other objects in the Solar System, the more we know about the Earth, at least in terms of geophysics and planetary geology. Our understanding of tides and tidal mechanics, and their relationship to tidal species and ecosystems, started with Astronomy. HST has more than paid for itself, in terms of scientific knowledge gained. |
|
Back to top |
|
 |
skconqueror

Joined: 31 Jul 2005
|
Posted: Tue Nov 01, 2005 5:42 am Post subject: |
|
|
mithridates wrote: |
R, are you serious? I've talked about the subject many times before, but the 8 to 1 return on investment into space technology is all you need to know. IOW, every $1 invested into NASA brings $8 in benefits to a nation's people.
Case #1: you're from Africa. Lots of Malaria there. Good weather satellites can predict when and where rain is going to fall so that you can take out mosquitoes before they breed. Otherwise you're going to just be spraying willy-nilly and wasting money. That in itself is worth the money.
If you want a few dozen other examples I have them, or you can check yourself. |
There is a big difference between how many moons does pluto have and weather satellites predicting the weather. I hope you seriously werent trying to make that leap  |
|
Back to top |
|
 |
mithridates

Joined: 03 Mar 2003 Location: President's office, Korean Space Agency
|
Posted: Tue Nov 01, 2005 6:20 am Post subject: |
|
|
There's no leap to be made. If you knew anything about the observation of space you'd know that the more results we have the easier it is to refine our tactics the next time. Also, using the Hubble to view other planets and moons helps us compare their environment to ours and make more accurate predictions about the weather here. The Hubble itself has also been a wonderful case study into doing repairs on things we've already put into orbit, and you never know when that might come in handy. IOW, just about everything in space development contributes to something else both within the industry and in others as well. |
|
Back to top |
|
 |
Leslie Cheswyck

Joined: 31 May 2003 Location: University of Western Chile
|
Posted: Tue Nov 01, 2005 6:48 am Post subject: |
|
|
Who knows, mith, maybe someday we can put a man on Uranus.
Last edited by Leslie Cheswyck on Tue Nov 01, 2005 2:18 pm; edited 1 time in total |
|
Back to top |
|
 |
mithridates

Joined: 03 Mar 2003 Location: President's office, Korean Space Agency
|
Posted: Tue Nov 01, 2005 7:09 am Post subject: |
|
|
Who knows. Anything's possible.
I wish everybody knew how it was really pronounced though. YER-a-nis.  |
|
Back to top |
|
 |
Leslie Cheswyck

Joined: 31 May 2003 Location: University of Western Chile
|
Posted: Tue Nov 01, 2005 2:40 pm Post subject: |
|
|
I understand rapier's point. Maybe space exploration is nothing more than an expensive hobby for Mankind. Yet, I know there are side benefits and perhaps even progress in science that can be advanced in no other way.
http://news.yahoo.com/s/space/20051101/sc_space/martiandustmajorrisktomannedmission
Martian Dust Major Risk to Manned Mission
Bjorn Carey
Staff Writer
SPACE.com
Tue Nov 1,10:00 AM ET
This past weekend, Mars swung closer to Earth than it will for the next decade, and coincidentally a dust storm kicked up and gave skywatchers something special to view.
While the red planet looks close enough to grab through a telescope, NASA doesn��t plan to send people there until after 2020, and even that far-off date could be pushed back by something as seemingly insignificant as dust.
According to a NASA report that evaluates the risks of sending a manned mission to Mars, Martian dust poses as one of the biggest potential problems.
Compared to here, dust on Mars is thought to be larger and rougher, like the dust that covers the Moon. When Apollo astronauts landed there, they were covered in just a few minutes. Within hours, rough lunar dust had scratched up lenses and degraded seals.
While the lunar stays were short, if astronauts make the six-month journey to Mars, they��ll likely be expected to stay a while. That would give potentially hazardous dust plenty of time to accumulate in equipment, cause airlock malfunctions, or even infiltrate astronauts�� lungs.
��Martian dust is a number one risk,�� says Jim Garvin, NASA chief scientist at the Goddard Space Flight Center. ��We need to understand the dust in designing power systems, space suits and filtration systems. We need to mitigate it, keep it out, figure out how to live with it.��
Perfect dust storm
Dust on Mars doesn��t just sit on the ground – it gets furiously swept about in dust devils and massive dust storms. This past weekend skywatchers could easily spot an 800-mile-wide dust storm as it spun across Mars at 35 mph.
Every once and a while, Mars experiences the ��perfect dust storm,�� where powerful winds kick dust up into the atmosphere where it is spread around until it eventually clouds the entire planet.
One of these rare storms would obviously make it difficult for a spacecraft to land or take off from the planet��s surface, but even smaller storms like the one this past weekend are a substantial mission risk, making atmospheric wind forces the number two mission risk, according to the report.
While dust and wind are two major mission risks, the team of scientists that contributed to NASA��s Mars Exploration Program Analysis Group report believe that future orbiters and robotic missions could help us better understand the planet and reduce these risks.
��We could observe Martian wind speeds at different altitudes, which is vital both for targeting accuracy when a mission lands, and for reaching the right orbit when the mission departs,�� said David Beaty, Mars Program Science Manager and the report��s lead author.
Lively dust?
Although signs of life haven��t been discovered on Mars, that might be a different story in 25 years. The possibility that microbial organisms, or their remains, could exist in Martian soil is ranked as the number three mission risk.
Having never been exposed to these forms of alien life, they could stand as a substantial health risk to astronauts. The biggest concern to scientists, though, is that these life forms might hitch a ride back to Earth, where they could replicate, prosper, and do unknown damage.
Scientists say they need more robotic missions and soil sample return to truly evaluate this risk. Even a couple pounds of Martian dirt would be of tremendous value, Beaty said.
Bodily harm?
Once on Mars, exposure to radiation is a relatively low risk, even for a long mission, according to the report. This evaluation is supported by data from the Mars Odyssey spacecraft.
However, during the year spent traveling between planets, astronauts will not be protected by a planet��s atmosphere and will be exposed to a greater dose of radiation. NASA says this amount falls within the lifetime safety limits, and protective spacesuits and ships are in the works.
Not mentioned in the report, however, are the physiological effects to bone and muscle from time spent in reduced gravity environments. Astronauts returning from long missions on the International Space Station have suffered massive muscle and bone loss. These losses would be slowed by Mars��s gravity, which is 3/8 of Earth��s, but it could be disastrous if a crewmember broke their leg during the mission.
Scientists are currently exploring methods of slowing muscle and bone deterioration, including an exercise device that creates its own gravity.
Useable water?
The roundtrip journey to the red planet and back will take about a year. The mission spacecraft can carry only so much water. Every gallon takes up space that could be used for other supplies or equipment and raises the total mission cost.
However, reducing the water load on the spacecraft could force the astronauts into a situation where they would run out of water before they returned to Earth, especially if their stay on Mars is longer than anticipated.
For a long mission, potable water in some form that��s accessible near the landing site could address this risk, scientists write in the report. Future orbiter and robotic missions could help identify a region on Mars where water might be available to astronauts, which could reduce the risk of astronauts running out of water.
Water is also a source of breathable oxygen, which, for a yearlong stay on the planet, would be expensive to transport.
|
|
Back to top |
|
 |
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
|