Earth's Orbit

[ramanisl]

Visualize the earth as it moves in its orbit around the Sun, Where does it's instantaneous velocity point to? What is the way to map this velocity to a relatively bright star it is roughly pointing at? The following article poses this as a question. The first person who posts a satisfactory answer will earn a simple honor. Visit 

 

http://newstudentresearch.blogspot.in/2017/02/what-are-we-hurtling-towards.html 

 

Srinivasan Ramani 

[Turtle]

Visualize the earth as it moves in its orbit around the Sun, Where does it's instantaneous velocity point to? What is the way to map this velocity to a relatively bright star it is roughly pointing at? The following article poses this as a question. The first person who posts a satisfactory answer will earn a simple honor. Visit 

 

http://newstudentresearch.blogspot.in/2017/02/what-are-we-hurtling-towards.html 

 

Srinivasan Ramani 

If you have something to discuss, post it here. Do not direct us off site.

[exchemist]

If you have something to discuss, post it here. Do not direct us off site.

Yes this seems to be a tiresome attempt to "test" members of this site, rather than to raise a point for discussion.

[OceanBreeze]

I’m not afraid of any test! :rolleyes:

 

Besides which, the question being asked is silly. The Earth has an infinite number of instantaneous velocities during each orbit and therefore can be pointing to an infinite number of different stars. Limiting the number of stars to the 92 brightest makes no sense since they are distributed randomly around us and Earth’s instantaneous orbital velocity will never be pointed directly at many of them (for example the North Star) unless something goes really wonky!

 

Oh, Srinivasan, just name my star Ernie. 

 

[exchemist]

Visualize the earth as it moves in its orbit around the Sun, Where does it's instantaneous velocity point to? What is the way to map this velocity to a relatively bright star it is roughly pointing at? The following article poses this as a question. The first person who posts a satisfactory answer will earn a simple honor. Visit 

 

http://newstudentresearch.blogspot.in/2017/02/what-are-we-hurtling-towards.html 

 

Srinivasan Ramani 

 

This seems on the face of it a pointless exercise. 

 

Can you explain why it might be of interest?

[ramanisl]

The question was 

At any moment, the earth, as a whole, has a velocity in relation to the solar system due to its orbital motion around the Sun. Consider the stars as providing a frame of reference. If you represent earth’s velocity as a vector, it is pointing roughly in the direction of some star. Given that there are 92 relatively bright stars in the sky (the Wikipedia lists 92 stars brighter than magnitude 2.49), it would be nice to find a way of mapping the earth’s orbital velocity on any given night to one of these 92 stars. Then we can tell anyone interested that the earth is hurtling that night roughly in the direction of that star.  What is a simple way to do this mapping?

(posted on the site I have referred to in this forum on my post dated 28 Feb 2017)

 

A sub-question was: Can every one of the 92 stars mentioned be mapped onto in this manner, during your lifetime? 

 

The first answer (it is by AJ) appears as a comment under my blog post. His answer is
 

My guess is that the star in that list, which is closest to the point of intersection of the ecliptic to the local meridian at sunrise would be the one we're hurtling towards. This is due to the fact that Earth's orbital motion at any instant would be perpendicular to the direction of the sun, in that direction. 

Sub answer: No, many of the stars in that list are nowhere close to the ecliptic, and earth's orbital plane doesn't precess enough in one lifetime for them to be in the direction of the vector of Earth's motion. 

 

"exchemist" had asked why this question might of interest. One answer is that it raises other questions of scientific interest. Example: Can we find meteor showers coming from the direction identified during particular days in a year? Meteors from such a shower would probably burn up better because their relative velocity to the earth is likely to be higher. On the other hand, meteors coming from a roughly opposite direction are likely to have a lower relative velocity on hitting the atmosphere. We may see more meteorites from such showers with a lower relative velocity.

[OceanBreeze]

 

The first answer (it is by AJ) appears as a comment under my blog post. His answer is

 

My guess is that the star in that list, which is closest to the point of intersection of the ecliptic to the local meridian at sunrise would be the one we're hurtling towards. This is due to the fact that Earth's orbital motion at any instant would be perpendicular to the direction of the sun, in that direction. 

Sub answer: No, many of the stars in that list are nowhere close to the ecliptic, and earth's orbital plane doesn't precess enough in one lifetime for them to be in the direction of the vector of Earth's motion. 

 

"exchemist" had asked why this question might of interest. One answer is that it raises other questions of scientific interest. Example: Can we find meteor showers coming from the direction identified during particular days in a year? Meteors from such a shower would probably burn up better because their relative velocity to the earth is likely to be higher. On the other hand, meteors coming from a roughly opposite direction are likely to have a lower relative velocity on hitting the atmosphere. We may see more meteorites from such showers with a lower relative velocity.

 

Bullshit. I was first and I want my star! :cussing:

[exchemist]

The question was 

At any moment, the earth, as a whole, has a velocity in relation to the solar system due to its orbital motion around the Sun. Consider the stars as providing a frame of reference. If you represent earth’s velocity as a vector, it is pointing roughly in the direction of some star. Given that there are 92 relatively bright stars in the sky (the Wikipedia lists 92 stars brighter than magnitude 2.49), it would be nice to find a way of mapping the earth’s orbital velocity on any given night to one of these 92 stars. Then we can tell anyone interested that the earth is hurtling that night roughly in the direction of that star.  What is a simple way to do this mapping?

(posted on the site I have referred to in this forum on my post dated 28 Feb 2017)

 

A sub-question was: Can every one of the 92 stars mentioned be mapped onto in this manner, during your lifetime? 

 

The first answer (it is by AJ) appears as a comment under my blog post. His answer is

 

My guess is that the star in that list, which is closest to the point of intersection of the ecliptic to the local meridian at sunrise would be the one we're hurtling towards. This is due to the fact that Earth's orbital motion at any instant would be perpendicular to the direction of the sun, in that direction. 

Sub answer: No, many of the stars in that list are nowhere close to the ecliptic, and earth's orbital plane doesn't precess enough in one lifetime for them to be in the direction of the vector of Earth's motion. 

 

"exchemist" had asked why this question might of interest. One answer is that it raises other questions of scientific interest. Example: Can we find meteor showers coming from the direction identified during particular days in a year? Meteors from such a shower would probably burn up better because their relative velocity to the earth is likely to be higher. On the other hand, meteors coming from a roughly opposite direction are likely to have a lower relative velocity on hitting the atmosphere. We may see more meteorites from such showers with a lower relative velocity.

I don't follow this logic. We already know on which days of the year the Earth encounters particular meteor swarms, and this has nothing to do with alignment with any stars.