Questions / Suggestions

“I want to give the audience a hint of a scene. No more than that. Give them too much and they won’t contribute anything themselves. Give them just a suggestion and you get them working with you. That’s what gives the theater meaning: when it becomes a social act.” –Orson Welles

It’s like that for all forms of storytelling, including the science I write about here. Some of the best conversations happen not because I know something amazing that I want to share with you, but because there’s something you want to know about, and I know something that can help you get to where you want to be. But since the platform migration that happened last year, there hasn’t been an easy way to do it, and yet I would, as Meaghan Smith would sing,

If You Asked Me.

So, do you have questions? Do you have suggestions?

Image credit: Thao Nelson of

Image credit: Thao Nelson of

Well, have I got something for you; look at what I finally created!

Your name:

That’s right, it’s the first-ever officially Ethan-approved way to contact me directly, even anonymously (or pseudonymously) as you like. The only catch is that anything you send me may be used by me, on this blog, as I like, as a prompt for however I may respond. And I caution you in advance, that may involve a little bit of…

Image credit: created at

Image credit: created at So watch it.

So let’s give it a whirl; it’s permanently available here as our third “Page”, along with my About Page and our Comments Policy Page. I’m sure you’re all trembling before my incredible coding skills to make this happen (that was sarcasm), but seriously, this was a big deal for me!

So enjoy the new question/suggestion submission form, and I look forward to hearing some great things from all of you!


  1. #1 j0h
    September 29, 2013

    Please look through my bad english. It is not my native language.

    Here you have mij email. Plz do not spread my email. TY

  2. #2 Lynn T Fergus
    Fillmore Ut.
    December 20, 2013

    I know i’m coming into the discussion late but I can’t find an answer to this question. Since no one knows what dark matter or dark energy are, how can we know if or how they might effect red shift?

  3. #3 Michael Kelsey
    SLAC National Accelerator Laboratory
    December 21, 2013

    @Lynn #2: Ethan has lots of much better explanations than I can provide, but I think this is simple: both dark matter (DM) and dark energy (DE) are _defined_ by how they affect our cosmological observations. That is, DM _is_ “whatever the stuff is that makes galaxies and clusters much more massive than the things we see with light”, and DE _is_ “whatever the effect is that is causing the expansion rate to increase with time, instead of decrease.”

    The big research project is to try to understand what physical stuff is causing those observations.

  4. #4 Lynn T Fergus
    Fillmore Ut
    December 24, 2013

    Michael, That still doesn’t answer how or if they effect red shift.

  5. #5 Michael Kelsey
    SLAC National Accelerator Laboratory
    December 25, 2013

    @Lynn #4: I guess I’m not entirely clear on what you’re asking.

    1) The expansion of the Universe causes us to observe a redshift of light emitted by distant galaxies. To the extent that the expansion rate of our Universe (containing DM and DE) is different from what it would be if it only contained baryonic matter, the redshift we observe is “affected” by DM and DE.

    2) Concentrations of mass cause a _gravitational_ redshift of light leaving their vicinity. We observe this on Earth and on the Sun. I’m not certain whether the effect is large enough to observe for galaxies or clusters (I rather doubt it). However, if the effect is observable, then the DM present will lead to a larger effect than if only the baryonic matter were there.

  6. #6 Sinisa Lazarek
    December 26, 2013

    @ Lynn

    It’s the other way around actually. I will try to use an analogy. Imagine your friend goes to another city by car. And he tells you that he will call you once he arrives. And let’s say that the car is traveling 100km/h and the city is 200 km away. Now, under normal circumstances, you would expect him to call in 2 hours. But he calls you 1:20 min. You know his car can’t go faster than 100km/h and you now when he left, thus the only conclusion you have is that “something” made his car go quicker… or something shrunk the road.

    We observe the red/blue shift. And since “c” is constant, we can only conclude that “something” messed up the wavelenght.

    One other important thing. Redshift caused by dark matter is different than the one caused by dark energy. DE and DM act very differently.

  7. #7 Sinisa Lazarek
    December 26, 2013

    p.s. DM acts as a regular gravitational shift. With lensing and so on. DE is a peculiar one. It acts on spacetime itself.

  8. #8 Lynn T Fergus
    December 26, 2013

    Thanks guys you really cleared it up for me.

  9. #9 Sinisa Lazarek
    December 28, 2013

    I’ve noticed a very interesting optic effect today on my wall. A small object on my coffee table cast a shadow on the wall, but a reflection which is not really visible on the glass, also cast a reflection of same opacity and size at exactly 90 degrees. Table top is not a mirror, but a transparent glass.

    Would appreciate very much if someone could explain what happens to light in this scenario. Question is about reflection casting a shadow in a particular case.

    I tried googling for it, but couldn’t find anything useful. Having read much about QED lately, am really curious how this effect occurs in QED terms. From point of view of the wall and some photons, both object and reflection are really the same, they cast exactly the same shadow. How come reflection’s shadow occurs in the first place, why isn’t it i.e. lighter or darker? But also it’s a transparent glass, yes from some angles a faint reflection is observed, yet it seems there’s an angle where it’s 100% reflected.. weird a bit again..

    here is a drawing I made to help illustrate it.

    Again, thank you if someone can explain in detail, or at least point me to correct articles. Maybe this effect has a technical name, that could help also. :)

    And sorry if this isn’t an appropriate topic… :)

  10. #10 Sinisa Lazarek
    December 28, 2013

    p.s. sorry… first sentence should read ” but a reflection which is not really visible on the glass, also cast a SHADOW of same opacity and size at exactly 90 degrees, ON THE WALL”

  11. #11 Sinisa Lazarek
    December 28, 2013

    * bump :(

  12. #12 J Duffield
    December 29, 2013


  13. #13 crd2
    February 15, 2014

    Bump test.

  14. #14 faisal jaradat
    September 22, 2014

    where can i read answers ?

  15. #15 Denis Thomas
    south carolina
    December 28, 2014

    Scientists often state that they do not know what time is, but know how to measure it accurately, which is an oxymora. Time is a system of information exchange, how God and men relate events with respect to the rotation of the earth: what you plan to do tomorrow; what you did last year; how long Jesus was in the tomb; how long it took God to create the universe; or how fast something travels all relate to the rotation of the earth. While gravity may affect time-measuring instruments, that is not proof that gravity affects time. If it did then two observers of a star, both located at exactly the same latitude but at a different longitude, such that one observer is a mile higher than the other, would observe the meridian containing the star cross their zenith at different times, with that difference in time increasing each year. You should recognize that this is impossible. Time slowing down or speeding up with speed is also impossible, but a concept derived from Einstein’s fallacy. His fallacy, while observing the clock at the train station and imagining the effects of observation of the clock as the train sped up to hypothetical speeds, was to ignore the time taken for the image from the clock to reach the point of observation. The clock did not slow down, nor did time.

  16. #16 dean
    December 28, 2014

    “Time slowing down or speeding up with speed is also impossible,”

    Since gps satellites would not give correct results without accounting for the effects of time dilation, and since it has been experimentally verified in other ways, your comment was demonstrated to be false before you made it.

  17. #17 jerry anning
    deaeborn hts, mi
    February 6, 2015

    when dark matter is discussed, it almost always talks in terms of something being “the” dark matter particle. is there a reason to assume that it’s not a mix of several kinds of particle?

  18. #18 Ragtag Media
    February 22, 2015

    The more agreeable I see the way people agree only tempers my soul to double fact check.


  19. #19 Wow
    February 23, 2015

    No, nothing stops it being multiple types of matter, Jerry. It’s called “Dark Matter” rather than “THE Dark Matter”, except where the context would make it generic, such as “The library is where you go to get a book to read”.

  20. #20 DGM
    April 23, 2015

    I understand that the Inflation Theory has the expansion of the universe being driven by an Inflation field that had negative pressure and hence pushed on space (negative gravity). And that as space expanded more of the field was created which pushed more. Hence the run-away inflation event that flattened the universe.

    But, when the field collapsed to it’s zero energy state (thus releasing all the energy that eventually became matter) space continued to expand. Why? This almost feels like inertia but space itself doesn’t have inertia (does it) and the energy/matter in space would be at rest as it has nowhere to go. So why did the expansion continue?

    I realize that now (12 billion years later) dark energy is starting to dominate and cause the expansion to speed up but what happened in the first few billion years when the matter and energy should have been pulling on space and causing it to contract?

  21. #21 Michael Kelsey
    SLAC National Accelerator Laboratory
    May 30, 2015

    @Ethan — following your Comments of the Week #62, I would find an overview of the different quantum gravity options extremely educational! Please consider this a “Yes” vote :-)

  22. #22 Jason B
    June 15, 2015

    I understand that the more dense gas clouds collapse to form the largest stars, and that the larger the star, the more short-lived its life.

    My question is how, then, are there still areas that produce massive stars? Are there areas in galaxies that are super dense but have yet to collapse? That seems unlikely. Are they remnants of past supernovae? That doesn’t seem like there would be enough dust.

    What am I missing?

  23. #23 Bpeth
    June 21, 2015

    I wrote up the answer to the weighing puzzle for any number of coins (or men on an island), see