CR4 - The Engineer's Place for News and Discussion®


Engineering News

Latest news of interest to engineers. Sourced from GlobalSpec's Engineering News

Previous in Blog: Future Headlights Turn Rain Invisible   Next in Blog: How A Nano-Suit Can Be A Life-Saver
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







45 comments

What Happens if the Moon Disappeared Tomorrow?

Posted April 27, 2013 6:24 PM

From Neatorama:

In Tom Cruise's latest movie Oblivion, the Moon was destroyed by an alien being and that unleashed a series of natural disasters that wrecked the Earth. But what exactly will happen if suddenly the Moon disappeared tomorrow?

Read the whole article

Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 9609
Good Answers: 523
#1

Re: What Happens if the Moon Disappeared Tomorrow?

04/27/2013 9:54 PM

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain - possibly to become "South Scotland" or "Non-Caledonia" from September 2016. Kettle's on.
Posts: 22847
Good Answers: 591
#11
In reply to #1

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 4:41 AM

There's a lot for that damn squirrel to answer!

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru
Engineering Fields - Optical Engineering - Member Engineering Fields - Engineering Physics - Member Engineering Fields - Systems Engineering - Member

Join Date: Apr 2010
Location: Trantor
Posts: 3863
Good Answers: 409
#2

Re: What Happens if the Moon Disappeared Tomorrow?

04/27/2013 11:21 PM

If the Moon disappeared completely, the tides changing is the obvious thing. And no more lunar or solar eclipses either, obviously.

The article mentions another thought I had - that Polaris would remain the Pole star. The major component of the Earth's wobble, where it's axis precesses in a circle taking 26,000 years, would go away, since this is almost entirely due to the Moon tugging on the Earth's equatorial bulge.

Seems to me there would be decreasing numbers of earthquakes and volcanoes, since some of the heat and flexing of the Earth's crust is due to the tidal effects of the Moon.

Another effect is that more asteroids would hit the Earth. On average the long-term effect - over thousands of years - is that the Moon acts as a barrier to asteroids, either directly taking the impact or using its gravity to deflect them away.

The other scenario, where it gets destroyed and not removed, would result in a ring, much like the one around Saturn. Some of that material would likely fall into the Earth and do damage. My guess is that the Earth's axis would still precess but at a slower rate, since the net torque on the Earth's equatorial bulge, caused by the debris ring, would be less.

__________________
Whiskey, women -- and astrophysics. Because sometimes a problem can't be solved with just whiskey and women.
Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 9030
Good Answers: 584
#3

Re: What Happens if the Moon Disappeared Tomorrow?

04/28/2013 1:42 AM

A key unstated factor here is how the moon disappears.

If the moon were to collide with the Earth to make a solitary planet, then the devastation would be enormous. For a very long time (millennia?) life may not be even possible on Earth.

If the moon was gradually tugged out of orbit then a relatively benign change in the Earth would probably happen. The tides will coincide with the day. The infrequent space debris impact on Earth may become more common. Nocturnal hunting would certainly be different. There might even be a difference in weather patterns but with the stated gradual removal it might be hard to notice.

Now between each of these fantasy scenarios lies a continuum of plausible fantasies. Take your pick.

__________________
Even the paranoid get lonely sometimes.
Reply
Guru
Popular Science - Evolution - New Member Popular Science - Weaponology - New Member

Join Date: May 2006
Location: The 'Space Coast', USA
Posts: 9567
Good Answers: 758
#7
In reply to #3

Re: What Happens if the Moon Disappeared Tomorrow?

04/28/2013 7:35 AM

All remotely possible scenarios... However...

A much more likely scenario would be that the Moon would simply be confiscated by the Murthin Brothers' Intergalactic Banking Services for failure to pay on our burgeoning national debt.

That deal was struck back in the 1990s.

Reply
Guru

Join Date: Apr 2011
Posts: 4262
Good Answers: 161
#4

Re: What Happens if the Moon Disappeared Tomorrow?

04/28/2013 3:22 AM

2 out of the first 3 comments suggest the risk of being hit by asteroids is reduced by having the moon in orbit.

.

I can understand the logic. I'm curious if the statements are just musings, of if there has been some rigorous analysis....perhaps that could be linked.

.

While the moon might swing object away from earth, it might also swing objects into earth.

In fact an object that narrowly misses earth, might come close enough to the moon for the trajectory to be changed enough for the earth to be in danger a second time.

Also as the combines moon-earth system has more mass than just earth, objects might be drawn from greater distances.

__________________
On a clover if alive erupts a vast pure evil a fire volcanO
Reply
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 15472
Good Answers: 552
#5

Re: What Happens if the Moon Disappeared Tomorrow?

04/28/2013 4:17 AM

Poachers would be angry.
Del

__________________
health warning: These posts may contain traces of nut.
Reply
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 8451
Good Answers: 361
#6

Re: What Happens if the Moon Disappeared Tomorrow?

04/28/2013 6:49 AM

It would certainly be a tense situation!

__________________
"Love justice, you who rule the world" - Dante Alighieri
Reply Off Topic (Score 5)
Guru

Join Date: Jun 2009
Location: South of Minot North Dakota
Posts: 5467
Good Answers: 492
#8

Re: What Happens if the Moon Disappeared Tomorrow?

04/28/2013 1:22 PM

What would women sync their cycles to then?

Without the moon they would be dropping them in any time the please and as long as they please.

Without the moon the red rage monster would start showing up at any time it wanted and possibly never leave when it's supposed too!

__________________
"Posting information on the internet is rather like casting seeds to the wind. Once it leaves your hand you have little chances of getting it back and no control over where it may land or what may sprout from it in the future." tcmtech.
Reply Score 1 for Off Topic
Power-User
Canada - Member - New Member Popular Science - Cosmology - New Member Hobbies - Musician - New Member

Join Date: Dec 2010
Location: Up North
Posts: 490
Good Answers: 25
#16
In reply to #8

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 7:58 AM

Oh, the horror! I can plan around the regular visits and avoid knocking up Mrs. North. And no, I won't go see a doctor for a bag of peas.

__________________
Steve of the North...since 1962.
Reply
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Ketchikan, AK, USA
Posts: 15519
Good Answers: 607
#9

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 2:47 AM

A flag and a golfball would also disappear, I guess, along with a rover or two.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain - possibly to become "South Scotland" or "Non-Caledonia" from September 2016. Kettle's on.
Posts: 22847
Good Answers: 591
#10

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 4:40 AM

Disappeared, as in ceases to be visible, or disappeared, as in becomes absent from Earth orbit?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru

Join Date: Jan 2006
Location: Tamworth, UK.
Posts: 665
Good Answers: 8
#12

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 4:59 AM

Here on Earth I guess we would have enormous earthquakes, erupting volcanos and floods as the earth settled into its new shape.

__________________
If you haven't made a mistake; you haven't made anything.
Reply
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 15472
Good Answers: 552
#14
In reply to #12

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 5:44 AM

Yeah, but as the moon is orbitting us it implies it's constantly pulling us hither and yon. Thus no moon would be less pulling to and fro, and I'd guess fewer earthquakes, erupting volcanoes and floods.
maybe poor old Mother Earth could just settle down, put her slippers on and have a nice cup of tea.
Del

__________________
health warning: These posts may contain traces of nut.
Reply
Guru

Join Date: Apr 2011
Posts: 4262
Good Answers: 161
#13

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 5:36 AM

I have some doubts about whether it is possible for the moon to disappear tomorrow, or actually if we can safely assume that the moon actually exists and appears tomorrow.

I think we should hold off using terms like 'disappear' when describing events suggested to occur during wholly-in-the-future time periods, until such time as we have a good idea about things like whether the moon already regularly 'appears' during such times.

.

At the very least, it is fairly certain that if the moon does somehow disappear tomorrow, no one will notice unless the tomorrow disappearance, until such a time (if ever) that the event propagates back into our familiar now.

__________________
On a clover if alive erupts a vast pure evil a fire volcanO
Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain - possibly to become "South Scotland" or "Non-Caledonia" from September 2016. Kettle's on.
Posts: 22847
Good Answers: 591
#15

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 6:23 AM

"Tomorrow never comes" - proverb.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru

Join Date: Oct 2007
Posts: 730
Good Answers: 70
#17

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 11:22 AM

Since the Earth/Moon system orbits the sun as a two piece object, it is the center of gravity of this system that follows the elliptical path around the sun. Each piece of the system (Earth or Moon) follows a more complex path, wobbling around the ellipse every month, speeding up and slowing down. If the moon 'disappeared' presumably its mass would also disappear. Depending on what part of the monthly wobble the Earth was in at that moment we would either be heading off into interstellar space or in towards the sun. We would either be travelling too fast for our current orbit, or too fast.

A pox on Tom Cruise and his alien friends...

Reply
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 15472
Good Answers: 552
#18
In reply to #17

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 11:38 AM

I think that would be true if the mass of the moon were greater to that of the earth.
moon is only about 1% of that of the Earth so I don't think we'd sail off anywhere.
Mind as it's hypothetical who givesadamn?

Del

__________________
health warning: These posts may contain traces of nut.
Reply
Guru

Join Date: Oct 2007
Posts: 730
Good Answers: 70
#19
In reply to #18

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 12:36 PM

We might not notice the change in orbit right away. But I think however small the change would be initially, time is very long, and since there is no countervailing force the orbital shift will grow unchecked and we would eventually feel the effect. But you are right - things the size of our moon don't 'disappear' leaving no trace. This problem is very low on my personal worry list...about as likely as Tom Cruise being in a scifi movie with any basis in science.

Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 9030
Good Answers: 584
#20
In reply to #19

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 1:24 PM

I think I hear Kepler and Newton turning over in their graves. The escape velocity from the sun at the Earth's nominal distance is 42.1 km/s. The aphelion and perihelion of Earth's orbit differs only about 5,000 km per year or about 0.16 km/s. The difference between the barycenter of the Earth/Moon system and the center of the the Earth is only 4641 km and a lunar cycle is about 27.5 days. So the total deviation wobble velocity from the moon is 0.0019 km/s. You're not even close enough to worry about escaping the sun.

__________________
Even the paranoid get lonely sometimes.
Reply
Guru

Join Date: Oct 2007
Posts: 730
Good Answers: 70
#21
In reply to #19

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 2:26 PM

I believe the worst case would be during the part of the lunar cycle where the earth is moving toward or away from the sun. Using your correct figures, 0.0019 km/sec works out to 6.84 km/hr, or 58,440.96 km/yr. I don't think we'd notice. After 100 years we'd be 5,844,096 km closer to or farther from the sun. We would notice the 12% change in solar radiation. In a few centuries we would be crossing the orbit of Venus or Mars, well outside the 'goldilocks' zone. That would be significant to the cockroaches or whoever was still clinging to life on our planet.

Reply Off Topic (Score 5)
Power-User
Hobbies - Musician - New Member

Join Date: Feb 2012
Posts: 307
Good Answers: 10
#22
In reply to #21

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 5:53 PM

Earth's motion is not toward or away from the Sun, is it? I believe it is tangential to its orbit. If the forward velocity increases, the Earth will move outward from the Sun until it is stable. If forward velocity decreases, the Earth will move inward until stable. Not a rocket surgeon, but I don't think the loss of the mass of Moon to the Earth/Moon/Sun dynamic would be change the Solar System too terribly in the short or long term.

Let's write up a grant proposal and run the experiment.

Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain - possibly to become "South Scotland" or "Non-Caledonia" from September 2016. Kettle's on.
Posts: 22847
Good Answers: 591
#25
In reply to #22

Re: What Happens if the Moon Disappeared Tomorrow?

04/30/2013 10:29 AM

Er, it's actually the other way round: velocity increase and smaller solar orbit go hand-in-hand, and velocity decrease and larger orbit go hand-in-hand. That's why a Martian "year" is longer than an Earth "year", for example.

Fortunately, the amount of mass present has a bearing on neither.

However, the amount of energy needed to remove the mass of the Moon from the Earth-Moon system is unimaginably large. As with all forms of energy dissipation, there is always some waste left as heat, and such a torment the Earth has not seen since the era of planetary accretion. On that basis, it isn't anything to worry about, as there would be no life surviving on Earth able to witness it.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Reply
Guru

Join Date: Apr 2011
Posts: 4262
Good Answers: 161
#27
In reply to #25

Re: What Happens if the Moon Disappeared Tomorrow?

04/30/2013 8:26 PM

'...Er, it's actually the other way round: velocity increase and smaller solar orbit go hand-in-hand, and velocity decrease and larger orbit go hand-in-hand.....'

.

Er, err.... While stable orbits with smaller radii will have higher velocities, and vise versa, it isn't correct to say velocity increases should go hand in hand with smaller orbits.

Reaching a larger/higher stable orbit from a lower stable orbit, is not something that will be accomplished by slowing orbiting object. Note that escape velocity decreases with distance from gravitational center. Also note that escape velocity is a large number and not zero.

While a large portion of the kinetic energy is used to overcome the negative potential energy of being trapped in a gravity well, ultimately causing the magnitude of the velocity to be lower than smaller than initially, this does not mean that a smaller orbit is caused by a velocity increase.

In the case of the earth/disappearing moon, if the mass of the moon disappeared at the right time to add to the orbital velocity of the earth, this increase would cause the earth's orbit to increase slightly, as the path widened the velocity would decrease until a new equilibrium is attained.

.

To reach escape velocity the speed would have to increase by more than 40%, and making the moon simply disappear isn't enough to cause a +40% increase in the orbital velocity of the earth.

So there would be no threat of earth drifting out into interstellar space.

__________________
On a clover if alive erupts a vast pure evil a fire volcanO
Reply
Guru
Popular Science - Evolution - New Member Popular Science - Weaponology - New Member

Join Date: May 2006
Location: The 'Space Coast', USA
Posts: 9567
Good Answers: 758
#29
In reply to #27

Re: What Happens if the Moon Disappeared Tomorrow?

04/30/2013 10:29 PM

Correct, but if the Moon were to suddenly disappear the Earth's orbit would no doubt be perturbed from the sudden change in momentum.

It would be an interesting computer simulation experiment to see how that would shake out for the various Earth-Moon positions when it suddenly happened.

Reply
Power-User
Hobbies - Musician - New Member

Join Date: Feb 2012
Posts: 307
Good Answers: 10
#34
In reply to #29

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 11:35 AM

A computer simulation is probably less expensive than what I was going to write up in my grant proposal, but I was thinking of trying to get the Dept of Defense interested in it.

The Earth/Moon system waltzes around a point, a center of gravity. For my mental model, which may not be at all accurate, I assume the orbital path around the Sun is the path of this center of gravity, not the Earth's center of gravity. If the Moon were suddenly removed from the equation (good thing I write in pencil and can easily make erasures) the center of gravity shifts from somewhere beneath the Earth's surface to the center of the Earth.

So, currently the Earth's center of gravity moves closer to the Sun and farther from the Sun as the Earth/Moon system revolve around their center of gravity. Without the Moon, the Earth stops moving to and fro and begins a less variable path. The shift of center of gravity is less than one Earth radius. Would that have immediate noticable effects? Hell if I know. Might just ring like a bell for a while.

Similarly, the Earth/Moon/Sun system revolve around a center of gravity beneath the Sun's surface but not at the Sun's center. Removal of the Moon from the equation will move that center of gravity closer to the Sun's center, but still not to the center. What happens to the Sun with that shift?

Where's a good Cosmologician when you need one?

Reply Score 1 for Good Answer
Guru

Join Date: Oct 2007
Posts: 730
Good Answers: 70
#38
In reply to #34

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 1:40 PM

"Without the Moon, the Earth stops moving to and fro and begins a less variable path."

I think you are almost right about this. I'd say that without the moon the cause of the Earth's variable path is removed, but the momentum it has at that instant (movement around the Sun + movement around the center of gravity of the Earth/Moon system) will be conserved. Depending on what part of the variable path Earth is in at that instant we would see a change in Earth's orbit. It could become larger, smaller, or more eccentric.

Reply Score 1 for Good Answer
Guru

Join Date: Oct 2007
Posts: 730
Good Answers: 70
#33
In reply to #22

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 11:14 AM

The motion of the barycenter (see post #20) of the Earth/Moon system is tangential to the Sun, but taken individually the components 'wobble' relative to this tangent over a period of 29 days. The Moon's wobble is quite visible - it is what we call the Moon's orbit. Sometimes the Moon is ~240 thousand miles toward the Sun from Earth and ~14 days later it is the same distance farther from the sun. So the Moon does not follow an elliptical path around the Sun, but a slightly skewed sinusoidal path.

Earth is much more massive and so it wobbles less since the barycenter is inside (but not at the center) the Earth. It does not follow a purely elliptical orbit, but like the Moon a sinusoidal path. So I'd say that there is a component of the Earth's motion that is 'toward or away from the sun'.

Just where the Earth is in this 29 day cycle when the Moon 'disappears' determines this component of its future path. If it happens to be moving toward the sun when the Moon (and more specifically the Moon's mass) disappears, the Moon won't be there to tug it back outward. Imagine you are on a dance floor and "swinging yer partner 'round and 'round" and then suddenly your partner 'disappears'. If your partner is big and you are small you go flying. If you are the big partner you will at least lose your balance. Since there's no friction and no dance floor in space you would be permanently off balance.

Reply
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 8451
Good Answers: 361
#23
In reply to #21

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 6:20 PM

__________________
"Love justice, you who rule the world" - Dante Alighieri
Reply Off Topic (Score 5)
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 9609
Good Answers: 523
#24

Re: What Happens if the Moon Disappeared Tomorrow?

04/29/2013 9:36 PM

No more Moon over my hammy at Denny's ?

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1305
Good Answers: 28
#26

Re: What Happens if the Moon Disappeared Tomorrow?

04/30/2013 11:49 AM

I am of the view - that NOTHING WILL HAPPEN for the reason that the MOON is orbitting the earth in a Circular Path and the Gravitational Force is linked ONLY TO EARTH and not to any other point.

If the moon is catapulted from its orbit it will follow NEWTON's FIRST LAW and keep travelling. If by chance some other object comes on its way then collission will occur.

The Ocean/Sea tides height on the new moon day and full moon day will not be there.

DHAYANANDHAN.S.

Reply Score 1 for Off Topic
Guru

Join Date: Apr 2011
Posts: 4262
Good Answers: 161
#28
In reply to #26

Re: What Happens if the Moon Disappeared Tomorrow?

04/30/2013 8:38 PM

'.... MOON is orbitting the earth in a Circular Path and the Gravitational Force is linked ONLY TO EARTH and not to any other point....'

.

That's curious. Is blue cheese only affected by the earth's gravity and not by the gravity of say, the sun?

Does blue cheese create the illusion of an elliptical orbit, but all the while the moon is secretly making a perfectly circular orbit?

How is it you are privy to such astonishing revelations?

__________________
On a clover if alive erupts a vast pure evil a fire volcanO
Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1305
Good Answers: 28
#32
In reply to #28

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 10:39 AM

Dear Mr truth is not a compramise,

The Moon-Earth gravity alone is the holding force. But Earth is linked to SUN and orbit around is elliptical and governed by KEPLER's LAW, which is known to you and all CR4 MEMBERS.

I for got to add one more point - in my first posting (See Posting No.26) " What Happens if the Moon Disappeared Tomorrow?"

IF THE MOON IS NOT THERE - There won't be full moon light for one day in every month and partial night moon light for the rest of the month, and for one day no moon light at all.

Few months back, on a similar discussions - I raised one doubt - The Orbit of planet (not satellite or satellite to the Planets) is travelling or orbitting at a very high speed - for the Earth, it is 18 Miles/sec. (or) 28.8 KM/Sec. Ellipse being VERY ENORMOUSLY LARGE in SIZE, ( MAJOR AXIS and MINOR AXIS in THOUSANDS of KILOMETRES) when the motion is parallel to the MAJOR AXIS, THE TRAVEL OF EARTH is ON SRTRAIGHT LINE and ACCORDING TO NEWTON's FIRST LAW, the EARTH should continue to travel straight and go away from Sun. But it is NOT so and sticks to ELLIPTICAL PATH, and the SPEED varies according to KEPLER's Law.

DHAYANANDHAN.S

Reply
Guru

Join Date: Apr 2011
Posts: 4262
Good Answers: 161
#39
In reply to #32

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 6:22 PM

It isn't just the Earth that is held in orbit around the Sun. Matter on the moon is no different than matter on the Earth...it is affected no differently.

.

Also, there are no flat spots on an ellipse. At every point there is curvature, with the exception of a degenerate ellipse (with an infinite radius).

.

The other way to look at it would be through the model of gravitationally distorted space-time, wherein the entire path of the planet is actually a geodesic....i.e. a straight line, the shortest path between two points.

__________________
On a clover if alive erupts a vast pure evil a fire volcanO
Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1305
Good Answers: 28
#35
In reply to #28

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 12:27 PM

Dear Mr.truth is not a compramise,

In my posting No. 32, in respose to your posting No.28, I want to add the following:

EARTH - Orbital Characteristics

epoch

J2000.0[nb 3]

aphelion

152,098,232 kilometres (94,509,460 mi)
1.01671388

AU[nb 4]

perihelion

147,098,290 kilometres (91,402,640 mi)
0.98329134 AU

[nb 4]

semimajor

149,598,261 kilometres (92,956,050 mi)
1.00000261 AU

[5]

eccentricity

0.01671123

[5]

inclination

7.155° to

Sun's equator
1.57869°[6] to invariable plane

asc_node

348.73936°

[1][nb 5]

arg_peri

114.20783°

[1][nb 6]

period

365.256363004 days

[7]
1.000017421 yr

avg_speed

29.78 kilometres per second (18.50 mi/s)

[1]
107,200 kilometres per hour (66,600 mph)

MY DOUBT - NEWTON's FIRST LAW DOES NOT WORK WHEN EARTH IS TRAVELLING IN PARALLEL TO MAJOR AXIS (which is 1 astronomical unit = DISTANCE BETWEEN SUN and EARTH)

I expect CR 4 Members to explain this phenomena.

DHAYANANDHAN.S

Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 9030
Good Answers: 584
#36
In reply to #35

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 12:44 PM

Newton's laws of motion always apply. The only tricky part that occasionally fool people is recognizing what inertial frame of reference should be used. That box of tissues on the dashboard of your car that slide to the right when you make a sharp left turn are not violating Newton's first law. Your frame of reference in the car is not an inertial frame. Forces are acting on you to change your velocity. The tissue box is not provided the proportional you are in the turn to match your change in velocity.

__________________
Even the paranoid get lonely sometimes.
Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1305
Good Answers: 28
#37
In reply to #36

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 12:57 PM

Thank you Mr. redfred,

for your good explanation.

Thanks,

DHAYANANDHAN.S

Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 9609
Good Answers: 523
#30

Re: What Happens if the Moon Disappeared Tomorrow?

04/30/2013 11:00 PM

We could finally get control of this werewolf epidemic.....

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Reply
Guru
Popular Science - Evolution - New Member Popular Science - Weaponology - New Member

Join Date: May 2006
Location: The 'Space Coast', USA
Posts: 9567
Good Answers: 758
#31
In reply to #30

Re: What Happens if the Moon Disappeared Tomorrow?

05/01/2013 8:48 AM

Let this be a lesson about personal hygiene.

First, always cut and trim your nails.

Two, cut down on those sweets and sodas as it really rots he teeth.

I won't comment about all the back hair.

Reply
Commentator

Join Date: Nov 2005
Posts: 98
Good Answers: 3
#40

Re: What Happens if the Moon Disappeared Tomorrow?

06/18/2013 3:11 PM

The Moon is critical to life on earth as we know it. The immediate effect on the tides and lack of moonlight is obvious as well as the other effects as mentioned above. But the Moon has many more critical functions aside from that.

As some have mentioned already, the moon is what stabilizes Earth's "wobble". What has not been mentioned is that this wobble is what gives us our seasons and without the consistency of the wobble our seasons would drift chaotically. This will result in major crop failures as the climate predictability goes out the window. This will lead to widespread famine accompanied by droughts, melting ice caps, and generally inhospitable and unpredictable conditions everywhere on Earth. This might take some time to take effect of course but still inevitable.

There would also be immediate massive flooding along coastal areas in higher latitudes. Don't forget that the Earth bulges at the equator due to the Moon's gravitational pull. This actually causes more water to accumulate in the equatorial region of the planet. With no moon, this bulge would subside and all that extra water at the equator would settle down and would disperse in the higher latitude regions, devastating much of the populated world. Conversely, there would be significant reduction in sea level at the equator, exposing coral reefs to the air and thereby destroying whole ecosystems. This inrush of water to the poles will likely have a very negative effect on the ice sheets. Ice floats right? Well, all that oceanic ice would want to lift up as the water rises and they would pull away from the rigid terrestrial glaciers. Who knows the effect this will have on the oceanic currents that play huge roles in keeping our northern climates warm. If these currents are disrupted we might even suffer a new ice age.

These are just the effects that are easily predicted. Surely there will be many other effects we can speculate about. With no real tidal effects on earth's crust I would expect fewer earthquakes at first but Earth's tectonic plates would still build up pressure. With fewer periodic earthquakes, I think there would be much more massive seismic events but less often.

There are countless species on Earth which rely on the phases of the Moon to reproduce and navigate for migration events. Surely there would be huge die off events as a result of confused animals around the globe.

NASA has confirmed other moon's that actually have molten cores due to tidal effects of their parent planets. How much of an effect does our moon have on our planet's internal temperature and dynamics? I'm not sure but now I'm just speculating.

But look on the bright side. The length of the day on Earth will stop increasing as the rotational speed of the Earth will no longer be slowed down by the Moon's gravitational friction. Astronomers will have less light pollution at night. And those property owners near the ocean where turtles lay their eggs will no longer have to black out their ocean facing windows because the turtles will likely all be dead and the risk of confusing them with our lights will be minimal.

__________________
Once everyone is super, no one will be. - "Incrediboy"
Reply Score 2 for Off Topic
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 8451
Good Answers: 361
#41
In reply to #40

Re: What Happens if the Moon Disappeared Tomorrow?

06/18/2013 7:09 PM

" ... this wobble is what gives us our seasons ..." - OFFS.

You prob'ly won't understand that, so I'll spell (most of it) out: "Oh, for f$ck's sake". Clear?

__________________
"Love justice, you who rule the world" - Dante Alighieri
Reply
Commentator

Join Date: Nov 2005
Posts: 98
Good Answers: 3
#42
In reply to #41

Re: What Happens if the Moon Disappeared Tomorrow?

06/19/2013 8:34 AM

I do not understand your response sir. My comment was not "off topic" and your response seems a bit out of place. Why would you use profanity in response to my post? The moon indeed serves to keep our planet's wobble in check. And without it Earth's wobble would resemble something like Mars'.

__________________
Once everyone is super, no one will be. - "Incrediboy"
Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 9030
Good Answers: 584
#43
In reply to #42

Re: What Happens if the Moon Disappeared Tomorrow?

06/19/2013 10:13 AM
Really?

The tilt of the Earth's spin axis from being parallel to the normal of the plane of our orbit around the sun is what gives us our seasons. (Remember, the normal of a plane is a defining vector perpendicular to the plane.) This tilt does wobble a very little bit and is known as the Chandler wobble. This is not to be confused with the nutation of the Earth's spin axis. The nutation is a periodic, predictable precession of our spin axis that comes from the gravitational attraction with the Moon and Sun. A wobble is random, not predictable effect.

Now Earth's axial tilt is more stabilized by the Moon. Mars in a chaotic obliquity state (spin axis tilt) due predominantly to the proximity with the outer gas giants and not a lack of a major moon. The time interval for Mars chaotic tilt changes are some millions of years. In anything but geologic and astronomical concerns this would be considered stable and not a wobble.

So, while you do have a valid point, the inaccurate use of wobble for tilt lead to a dismissal of your point. The rudeness was inappropriate.

__________________
Even the paranoid get lonely sometimes.
Reply
Commentator

Join Date: Nov 2005
Posts: 98
Good Answers: 3
#44
In reply to #43

Re: What Happens if the Moon Disappeared Tomorrow?

06/26/2013 9:57 AM

Sir, I am a layman in this field and claim no expertise. That being said, I will assume that your clarification is accurate as I have no reason to suspect otherwise. Perhaps it would have been more accurate if I had said that the moon did not cause the "axial tilt" but nevertheless sustains it in a way that our ice caps can remain stable for long periods of time.

The assertion you are making about Jupiter's and other gas giants influence on Mars' tilt seems a bit far fetched though. If those planets were affecting Mars then we could expect that Mars' orbit around the sun would be drastically changing whenever Mars and Jupiter were on the same side of the sun. Even as a laymen, I would classify that comment as incorrect. Jupiter is big, but not that big.

I just thought it would be fun to imagine the Earth without a Moon and my main motivation for the post was to point out that the removal of our Moon would change Earth so drastically that we would have a lot more to worry about than werewolves going extinct.

I think we can agree that the removal of our moon would devastate the planet Earth as we know it. That is the point I was driving towards. How about that sir? Would you take issue with that point? Do you think the result would be merely fewer romantic nights or widespread destruction (short or long term).

__________________
Once everyone is super, no one will be. - "Incrediboy"
Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 9030
Good Answers: 584
#45
In reply to #44

Re: What Happens if the Moon Disappeared Tomorrow?

06/26/2013 10:48 AM

I go back to my initial point, the effect on the Earth by the loss of the Moon will depend predominately on the unstated reason how the Moon leaves orbit and not the absence itself. If the Moon "disappears" by a collision with another body imparting sufficient energy for the pair to leave Earth orbit then a host of different severe things affecting life on Earth are possible immediately after impact. (Remember when talking about planetary motions, a century can be considered a short amount of time.)

__________________
Even the paranoid get lonely sometimes.
Reply
Reply to Blog Entry 45 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Anonymous Hero (3); Del the cat (3); dhayanandhan (4); horace40 (1); JohnDG (3); johnfotl (5); PWSlack (4); redfred (5); reward54 (2); SmithsEng (3); SolarEagle (3); Steve of the North (1); tcmtech (1); Tornado (1); truth is not a compromise (5); Usbport (1)

Previous in Blog: Future Headlights Turn Rain Invisible   Next in Blog: How A Nano-Suit Can Be A Life-Saver

Advertisement