The Naked Scientists
  • Login
  • Register
  • Podcasts
      • The Naked Scientists
      • eLife
      • Naked Genetics
      • Naked Astronomy
      • In short
      • Naked Neuroscience
      • Ask! The Naked Scientists
      • Question of the Week
      • Archive
      • Video
      • SUBSCRIBE to our Podcasts
  • Articles
      • Science News
      • Features
      • Interviews
      • Answers to Science Questions
  • Get Naked
      • Donate
      • Do an Experiment
      • Science Forum
      • Ask a Question
  • About
      • Meet the team
      • Our Sponsors
      • Site Map
      • Contact us

User menu

  • Login
  • Register
  • Home
  • Help
  • Search
  • Tags
  • Recent Topics
  • Login
  • Register
  1. Naked Science Forum
  2. Non Life Sciences
  3. Physics, Astronomy & Cosmology
  4. If the Sun travelled at c towards Earth, how long before it arrives?
« previous next »
  • Print
Pages: [1]   Go Down

If the Sun travelled at c towards Earth, how long before it arrives?

  • 12 Replies
  • 6655 Views
  • 0 Tags

0 Members and 1 Guest are viewing this topic.

This topic contains a post which is marked as Best Answer. Press here if you would like to see it.

guest39538

  • Guest
If the Sun travelled at c towards Earth, how long before it arrives?
« on: 30/06/2016 10:42:07 »
As title question.

added - after pausing for thought, another question, what time does it arrive?

 [ Invalid Attachment ]

added - I may have it a bit backward, but relatively we see the sun in its past, so how can the past catch up with the present?


added- I think the Sun would show 12:08 am while the Earth clock shows 12, but hopefully you get the question.

* sun.jpg (34.98 kB, 719x446 - viewed 826 times.)
Logged
 



Offline jeffreyH

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6996
  • Activity:
    0%
  • Thanked: 192 times
  • The graviton sucks
Re: If the Sun travelled at c towards Earth, how long before it arrives?
« Reply #1 on: 30/06/2016 11:03:34 »
The relativistic mass of the sun would be infinite so I suggest throwing the laws of physics out of the window and taking up a creative writing course.
Logged
Even the most obstinately ignorant cannot avoid learning when in an environment that educates.
 

guest39538

  • Guest
Re: If the Sun travelled at c towards Earth, how long before it arrives?
« Reply #2 on: 30/06/2016 11:08:19 »
Quote from: jeffreyH on 30/06/2016 11:03:34
The relativistic mass of the sun would be infinite so I suggest throwing the laws of physics out of the window and taking up a creative writing course.

I am not quite sure how that answers the question , I was rather hoping for some maths for the answer.

Seemingly the Sun could strike the Earth and we would not notice it had even moved because of the light/sight delay of 8 minutes.  Something seems to be flawed unless I am misunderstanding something?

Logged
 

Offline jeffreyH

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6996
  • Activity:
    0%
  • Thanked: 192 times
  • The graviton sucks
Re: If the Sun travelled at c towards Earth, how long before it arrives?
« Reply #3 on: 30/06/2016 11:17:51 »
Quote from: Thebox on 30/06/2016 11:08:19
Quote from: jeffreyH on 30/06/2016 11:03:34
The relativistic mass of the sun would be infinite so I suggest throwing the laws of physics out of the window and taking up a creative writing course.

I am not quite sure how that answers the question , I was rather hoping for some maths for the answer.

Seemingly the Sun could strike the Earth and we would not notice it had even moved because of the light/sight delay of 8 minutes.  Something seems to be flawed unless I am misunderstanding something?

You are absolutely correct. Since the sun would be traveling at the same speed as the photons it would appear to an observer (at a safe distance. ie another universe  [;D]) that the sun had moved instantaneously from its initial position to its final position next to the earth.
Logged
Even the most obstinately ignorant cannot avoid learning when in an environment that educates.
 

guest39538

  • Guest
Re: If the Sun travelled at c towards Earth, how long before it arrives?
« Reply #4 on: 30/06/2016 11:27:39 »
Quote from: jeffreyH on 30/06/2016 11:17:51
Quote from: Thebox on 30/06/2016 11:08:19
Quote from: jeffreyH on 30/06/2016 11:03:34
The relativistic mass of the sun would be infinite so I suggest throwing the laws of physics out of the window and taking up a creative writing course.

I am not quite sure how that answers the question , I was rather hoping for some maths for the answer.

Seemingly the Sun could strike the Earth and we would not notice it had even moved because of the light/sight delay of 8 minutes.  Something seems to be flawed unless I am misunderstanding something?

You are absolutely correct. Since the sun would be traveling at the same speed as the photons it would appear to an observer (at a safe distance. ie another universe  [;D]) that the sun had moved instantaneously from its initial position to its final position next to the earth.
Hmm, interesting somebody agrees with something I said, thanks.  You have failed to discuss the times though?


If it is 12am on Earth I see the Sun as it were at 11:52pm?

So at example 12:000000000000000000000000000001am, the Sun could instantly kill me by collision and I would not see it coming literally because it is already on its way and as already travelled most of the distance I am not even aware of?




Logged
 



Offline jeffreyH

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6996
  • Activity:
    0%
  • Thanked: 192 times
  • The graviton sucks
Re: If the Sun travelled at c towards Earth, how long before it arrives?
« Reply #5 on: 30/06/2016 11:36:27 »
If we wish to move a mass at 1 metre in 1 second then the force can be derived from the mass alone. So that increasing the mass is a direct reflection of the increase in the required force. If we make the mass infinite then the force required to move it is infinite. Since the gamma function produces an infinite mass at the speed of light we can show a relationship between these two situations. In the first we are increasing the inertial mass in order to affect the magnitude of the force required. In the second we are increasing the relativistic mass which achieves a similar result. The difference between the two is that the first is governed by newtonian mechanics and the second by relativistic mechanics.
Logged
Even the most obstinately ignorant cannot avoid learning when in an environment that educates.
 

Offline jeffreyH

  • Global Moderator
  • Naked Science Forum King!
  • ********
  • 6996
  • Activity:
    0%
  • Thanked: 192 times
  • The graviton sucks
Re: If the Sun travelled at c towards Earth, how long before it arrives?
« Reply #6 on: 30/06/2016 11:39:18 »
Quote from: Thebox on 30/06/2016 11:27:39
Quote from: jeffreyH on 30/06/2016 11:17:51
Quote from: Thebox on 30/06/2016 11:08:19
Quote from: jeffreyH on 30/06/2016 11:03:34
The relativistic mass of the sun would be infinite so I suggest throwing the laws of physics out of the window and taking up a creative writing course.

I am not quite sure how that answers the question , I was rather hoping for some maths for the answer.

Seemingly the Sun could strike the Earth and we would not notice it had even moved because of the light/sight delay of 8 minutes.  Something seems to be flawed unless I am misunderstanding something?

You are absolutely correct. Since the sun would be traveling at the same speed as the photons it would appear to an observer (at a safe distance. ie another universe  [;D]) that the sun had moved instantaneously from its initial position to its final position next to the earth.
Hmm, interesting somebody agrees with something I said, thanks.  You have failed to discuss the times though?


If it is 12am on Earth I see the Sun as it were at 11:52pm?

So at example 12:000000000000000000000000000001am, the Sun could instantly kill me by collision and I would not see it coming literally because it is already on its way and as already travelled most of the distance I am not even aware of?

The mathematics for this situation are undefined by definition but technically you are going in the right direction.
« Last Edit: 30/06/2016 11:42:03 by jeffreyH »
Logged
Even the most obstinately ignorant cannot avoid learning when in an environment that educates.
 

guest39538

  • Guest
Re: If the Sun travelled at c towards Earth, how long before it arrives?
« Reply #7 on: 30/06/2016 11:43:04 »
Quote from: jeffreyH on 30/06/2016 11:36:27
If we wish to move a mass at 1 metre in 1 second then the force can be derived from the mass alone. So that increasing the mass is a direct reflection of the increase in the required force. If we make the mass infinite then the force required to move it is infinite. Since the gamma function produces an infinite mass at the speed of light we can show a relationship between these two situations. In the first we are increasing the inertial mass in order to affect the magnitude of the force required. In the second we are increasing the relativistic mass which achieves a similar result. The difference between the two is that the first is governed by newtonian mechanics and the second by relativistic mechanics.

Sorry Jeff I am struggling to see the relationship to your post and the topic, I am also struggling today to understand what you are on about, I do understand when you say a infinite force to move an infinite mass but other than that I am lost to your intent and the relationship.

added - or are you trying trying to say it is impossible to move the Sun type thing?



Logged
 

Marked as best answer by on 05/07/2025 22:58:17

Offline Alan McDougall

  • Naked Science Forum King!
  • ******
  • 1285
  • Activity:
    0%
  • Thanked: 16 times
  • Undo Best Answer
  • Re: If the Sun travelled at c towards Earth, how long before it arrives?
    « Reply #8 on: 30/06/2016 12:44:31 »
    It would arrive later than expected, how much later , that is a moot point.
    Logged
    The Truth remains the Truth regardless of our beliefs or opinions the Truth is always the Truth even if we know it or do not know it (The Truth remains the Truth)
     



    Offline IAMREALITY

    • Sr. Member
    • ****
    • 275
    • Activity:
      0%
    • Thanked: 11 times
    Re: If the Sun travelled at c towards Earth, how long before it arrives?
    « Reply #9 on: 30/06/2016 15:57:37 »
    Quote from: Thebox on 30/06/2016 11:27:39
    Quote from: jeffreyH on 30/06/2016 11:17:51
    Quote from: Thebox on 30/06/2016 11:08:19
    Quote from: jeffreyH on 30/06/2016 11:03:34
    The relativistic mass of the sun would be infinite so I suggest throwing the laws of physics out of the window and taking up a creative writing course.

    I am not quite sure how that answers the question , I was rather hoping for some maths for the answer.

    Seemingly the Sun could strike the Earth and we would not notice it had even moved because of the light/sight delay of 8 minutes.  Something seems to be flawed unless I am misunderstanding something?

    You are absolutely correct. Since the sun would be traveling at the same speed as the photons it would appear to an observer (at a safe distance. ie another universe  [;D]) that the sun had moved instantaneously from its initial position to its final position next to the earth.
    Hmm, interesting somebody agrees with something I said, thanks.  You have failed to discuss the times though?


    If it is 12am on Earth I see the Sun as it were at 11:52pm?

    So at example 12:000000000000000000000000000001am, the Sun could instantly kill me by collision and I would not see it coming literally because it is already on its way and as already travelled most of the distance I am not even aware of?

    Pretty much...

    Thankfully, as Jeffrey has referenced, such a scenario need not keep us up at night, since it would take an infinite amount of force to move the sun that fast to begin with...

    I would also wager that the sun would've killed you long before 12:00000000...1 am...  But you still wouldn't have seen it comin...
    Logged
     

    Offline Colin2B

    • Global Moderator
    • Naked Science Forum King!
    • ********
    • 6476
    • Activity:
      0%
    • Thanked: 708 times
    Re: If the Sun travelled at c towards Earth, how long before it arrives?
    « Reply #10 on: 30/06/2016 21:37:23 »
    I'm assuming the sun starts its journey at 1152 - that is the time on both the sun and earth. At 1152 Earth is seeing the light which left the sun at 1144.
    If we assume the sun accelerates instantaneously to light speed and ignoring relativistic mass effects, then the sun along with its light and heat will all arrive together at 1200. There would be no warning.

    Of much greater interest is the question "what caused this?"

    PS I'm ignoring the photosphere which would arrive marginally before the sun's surface.

    « Last Edit: 30/06/2016 21:40:27 by Colin2B »
    Logged
    and the misguided shall lead the gullible,
    the feebleminded have inherited the earth.
     

    guest39538

    • Guest
    Re: If the Sun travelled at c towards Earth, how long before it arrives?
    « Reply #11 on: 01/07/2016 10:13:27 »
    Quote from: Colin2B on 30/06/2016 21:37:23


    Of much greater interest is the question "what caused this?"



    I am subjecting you to my thinking............................caused ''this''
    Logged
     

    Offline alancalverd

    • Global Moderator
    • Naked Science Forum GOD!
    • ********
    • 21159
    • Activity:
      68%
    • Thanked: 60 times
    • Life is too short for instant coffee
    Re: If the Sun travelled at c towards Earth, how long before it arrives?
    « Reply #12 on: 01/07/2016 10:22:29 »
    Quote from: jeffreyH on 30/06/2016 11:17:51
    You are absolutely correct. Since the sun would be traveling at the same speed as the photons it would appear to an observer (at a safe distance. ie another universe  ;D) that the sun had moved instantaneously from its initial position to its final position next to the earth.


    Not true unless the observer was in the line of travel of the sun. From a position at 90 degrees to that line, the sun would be seen to move.
    Logged
    Helping stem the tide of ignorance
     
    The following users thanked this post: jeffreyH



    • Print
    Pages: [1]   Go Up
    « previous next »
    Tags:
     
    There was an error while thanking
    Thanking...
    • SMF 2.0.15 | SMF © 2017, Simple Machines
      Privacy Policy
      SMFAds for Free Forums
    • Naked Science Forum ©

    Page created in 0.699 seconds with 57 queries.

    • Podcasts
    • Articles
    • Get Naked
    • About
    • Contact us
    • Advertise
    • Privacy Policy
    • Subscribe to newsletter
    • We love feedback

    Follow us

    cambridge_logo_footer.png

    ©The Naked Scientists® 2000–2017 | The Naked Scientists® and Naked Science® are registered trademarks created by Dr Chris Smith. Information presented on this website is the opinion of the individual contributors and does not reflect the general views of the administrators, editors, moderators, sponsors, Cambridge University or the public at large.