Science & Mathematics

Very simply.
When Hubble looks at a star, it is literally looking into the past. Because light travels at a finite (and constant) speed, we observe things long after they actually happen.

The earth has been on its journey for 4.6 billion years.
So, if I point Hubble to a point where the earth would have been say 1 million years ago why can't I see it?

I know it has something to do with the relative position of the observer. And I know it something to do with causality... but can someone explain the physical law that governs WHY Hubble could not target earth sometime in the past?

2007-12-31 04:08:00 · 6 answers · asked by acyberwin 5 in Physics

How do you solve for X in matrixes?

For example please explain how ([-2x 11] - ([-13 -12]) + [ 0 17] = [23 28 ]


Please explain and give answer and you'll get best answer!

2007-12-31 04:07:38 · 2 answers · asked by Jaz 'ma' Taz 2 in Mathematics

Hi,
I'm sure you guys are getting tired of my equilibrium questions by now... but here's a last really quick one:
For:
NH4HS (s) <--> NH3 (g) +H2S (g)

If you add more NH4HS (s) to the container, does the partial pressure of NH3 (g):
1- Stay the same because the air is already "saturated" with the NH3 and H2S gas, so that no more of the solid can reach the gaseous state,
or
2- Increase because more NH4HS is trying to reach a gaseous state, separating into more NH3 and H2S gas particles, therefore increasing the partial pressure of NH3 gas in the air?

Thanks in advance!

2007-12-31 04:07:15 · 5 answers · asked by Alyssy 2 in Chemistry

Today I answered a simple problem of trigonometry and was the first to solve it. But someone had just posted the question only as an answer before me and edited it with the answer after seeing my answer. Now it appears that he was the first to solve. What should be done to discourage such an unethical practice?

2007-12-31 04:06:32 · 7 answers · asked by Madhukar 7 in Mathematics

I'm told that if I were to 'train' a slug to navigate a maze for food for example and then I were to liquidise that slug and feed it to another slug the second slug would know the route.
It's called chemical memory which I believe is real but I'm not sure if this 'fact' is. Anyone know?

2007-12-31 04:06:16 · 7 answers · asked by Ben C 1 in Chemistry

A.x=3
B.x= -75
C.x= -13
D.x= 35

2007-12-31 04:05:25 · 8 answers · asked by Anonymous in Mathematics

the tower has to be at least 11inches tall and i cannot roll up the index cards, i can fold them or staple them

2007-12-31 04:04:53 · 8 answers · asked by bryan t 1 in Engineering

2007-12-31 03:59:56 · 4 answers · asked by dean 4 in Physics

which variables on a weather chart would help predict the weather for the next day?

2007-12-31 03:58:56 · 2 answers · asked by Anonymous in Weather

I've heard of Saxon amongst other brands... please help?

2007-12-31 03:56:43 · 6 answers · asked by Katie 2 in Astronomy & Space

How can we detect neutrino, it has little more than 0 mass with no charge. It can pass through anything, doesn't make scintillation.
And what information we can infer from it if we detect it?
I parted with physics long ago and I have forgotten many things and all my current knowledge is corrupted by hundreds of sci-fi movies and discovery channel docs.
Thank you and a happy new year..

2007-12-31 03:54:41 · 7 answers · asked by Fantail Flycatcher 3 in Astronomy & Space

Pseudoephedrine hydrochloride (decongestant) ,with paracetamol , and diclofenac Sodium ( Dicloflex 50mg).

2007-12-31 03:54:09 · 12 answers · asked by Luke L 2 in Medicine

2007-12-31 03:51:30 · 2 answers · asked by guru r 1 in Weather

A.x= -144
B.x= -336
C.x= -7/3
D.x= -1

2007-12-31 03:49:49 · 12 answers · asked by Anonymous in Mathematics

when the motor is running 24hrs a day all year long, I am refering to a air compressor

2007-12-31 03:49:10 · 8 answers · asked by Jessyca E 1 in Engineering

2007-12-31 03:48:48 · 6 answers · asked by Andreu 2 in Earth Sciences & Geology

1) A 900kg car traveling at 105 km/h runs into a tree and comes to a stop in 700ms. what is the average force exerted on the tree?

2) A rocket mass 500kg is propelled vertically upwards by a motor producing a force of 7kN. What is its acceleration?

3) An artificial satellite is placed in a circular orbit with a peroid of 16.0 days around Larissa, a moon of neptune. An on-board altimeter measures the distance to the surface of Larissa to be 2500km, which is much greater than the radius of the moon. Estimate Larissa's mass.

Please show workings and the general equations used to work them out. Many thanks in advance

2007-12-31 03:48:26 · 2 answers · asked by marc e 1 in Physics

I've tried substituting secA for 1/cosA but not really getting anywhere. Answer is supposed to be 17.5, but I have no idea how to get there! Any help would be much appreciated.

2007-12-31 03:45:54 · 5 answers · asked by Anonymous in Mathematics

2007-12-31 03:43:23 · 7 answers · asked by Turgut y 1 in Physics

2007-12-31 03:41:20 · 5 answers · asked by Andreu 2 in Earth Sciences & Geology

you must use all four numbers. For example, the numbers 5, 5, 8, 8 can equal 24 as follows: 5*5-8/8
also, reversed order only counts as one
I already have one. (3/7+3)*7
can anyone think of any others

2007-12-31 03:41:13 · 3 answers · asked by Anonymous in Mathematics

2007-12-31 03:38:00 · 4 answers · asked by dean 4 in Physics

2007-12-31 03:36:24 · 2 answers · asked by Anonymous in Chemistry

is it possible to seperate carbon and oxygen in hot environment before production of CO or CO2 by charging oxygen and carbon ( by electric charge) and then seperate them by electric field? or by using of a another (cheap) matter(S) to react with one of them ( more desirably with carbon) to prevent of production of CO and CO2?

2007-12-31 03:35:46 · 1 answers · asked by arahmaninejad 1 in Chemistry

2007-12-31 03:29:15 · 6 answers · asked by Wallace 2 in Mathematics

2007-12-31 03:29:07 · 12 answers · asked by Anonymous in Astronomy & Space

math WAS my best subject in school. but i am really drawing a blank here. what is one-half of two-thirds? and could you please explain how you get the answer?!! thanks

2007-12-31 03:28:21 · 11 answers · asked by stevies_mom 3 in Mathematics

2007-12-31 03:27:03 · 3 answers · asked by Anonymous in Zoology

1:How many liters of oxygen (O2) are needed to convert 100 liters of hydrogen (H2) to water (H2O)?
2:How many liters of hydrogen chloride (HCl) may be produced from 100 liters of H2?
3:How many cubic feet of oxygen (O2) are needed to convert 100 cubic feet (100cf) of carbon monoxide (CO) to carbon dioxide (CO2)?
4:How many liters of oxygen (O2) must react with sulfur dioxide (SO2) to produce 50 liters of sulfur trioxide (SO3)?
5:How many liters of hydrogen (H2) are needed to produce 100 liters of ammonia (NH3) by direct combination with nitrogen?
6:How many milliliters of carbon dioxide (CO2) can be formed when carbon (C) is burned in 1 liter of oxygen (O2)?
7:If 10 liters of hydrogen (H2) weigh 1.0g, and 10 liters of oxygen (O2) weigh 16g, how much would 10 liters of water vaper weigh?
8:If 20 liters of carbon monoxide(CO) weigh 28g, and 20 liters of oxygen (O2) weigh 32g, how much would 20 liters of carbon dioxide weigh?

2007-12-31 03:21:13 · 3 answers · asked by Ashley G 1 in Chemistry

basicly what my question states.

2007-12-31 03:19:39 · 5 answers · asked by Mary G 1 in Medicine