Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.
  • Home Home Home, current page.
  • Moments Moments Moments, current page.

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
neiltyson's profile
Neil deGrasse Tyson
Neil deGrasse Tyson
Neil deGrasse Tyson
Verified account
@neiltyson

Tweets

Neil deGrasse TysonVerified account

@neiltyson

Astrophysicist

New York City
haydenplanetarium.org/tyson/
Joined January 2009

Tweets

  • © 2018 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    Neil deGrasse Tyson‏Verified account @neiltyson 17 Jan 2013

    .@cmirand4: Why doesn't the speed of light have an uncertainty? // It's defined, not measured. See: http://bit.ly/W7tlVF 

    11:47 AM - 17 Jan 2013
    • 233 Retweets
    • 223 Likes
    • Tommy Kristina  Ⓥ Cynthia Vera Isabella Rosa Emma Lintvelt John Greer Aaron Kreienheder 2-1 xandercoded
    48 replies 233 retweets 223 likes
      1. New conversation
      2. Miles Tougeaux‏ @milestougeaux 17 Jan 2013
        Replying to @neiltyson

        @neiltyson @cmirand4 But isnt the speed of light relative as a function of gravity?

        5 replies 1 retweet 1 like
      3. 1 more reply
      1. Steven Clark‏ @Nullcast 25 Jan 2013
        Replying to @neiltyson

        @neiltyson @cmirand4 to clarify (we cheat) the length of a meter is defined in terms of C and the time standard, also wikipedia works here

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. BlackPhysicists‏ @BlackPhysicists 21 Jan 2013
        Replying to @neiltyson

        @neiltyson @cmirand4 Speed of light has been / can be measured cf Michelson expts and Lene Hau's work

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Ed Ciecierski‏ @khorvus 18 Jan 2013
        Replying to @neiltyson

        Hmm RT @neiltyson .@cmirand4: Why doesn't the speed of light have an uncertainty? // It's defined, not measured. See: http://bit.ly/W7tlVF 

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Kurt van Krieken‏ @raevn1 18 Jan 2013
        Replying to @neiltyson

        @neiltyson had no idea pi had such an old history, or that we had tracked it. As for constants, with how little time we have been who knows

        1 reply 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Paul Grems Duncan‏ @grems8544 18 Jan 2013
        Replying to @neiltyson

        @neiltyson I would enjoy an essay on Einstein and the background of the constant of light. Your article on "...Being Constant" was great. TY

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Violin 🎶 🎶 🎶‏ @LorindaswanRad 18 Jan 2013
        Replying to @neiltyson

        @neiltyson I'm going to be stalking the Hayden planetarium tomorrow. I will be stealthy.

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Dr. Neenah Estrella-Luna‏ @nstarluna 18 Jan 2013
        Replying to @neiltyson

        @neiltyson Thank you for giving me the base for next week's discussion with my doc students: the relationship b/n social science & physics.

        1 reply 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. eddie sanchez‏ @ejsanchezjr 18 Jan 2013
        Replying to @neiltyson

        @neiltyson great read but my ? is Can we ever really know the circumference AND the radius of a circle if exact value of pi is unknown?

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. ullrsdream‏ @ullrsdream 18 Jan 2013
        Replying to @neiltyson

        @neiltyson @cmirand4 Thanks for the article - too bad it says of the speed of light only "a subject worthy of its own essay at another time"

        1 reply 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Lynn‏ @lost_sisterhood 18 Jan 2013
        Replying to @neiltyson

        @neiltyson I love how you turn physics into poetry.

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Robert Smith‏ @rsmith31415 17 Jan 2013
        Replying to @neiltyson

        @neiltyson @cmirand4 Not entirely true. See http://en.wikipedia.org/wiki/Speed_of_light#Increased_accuracy_of_c_and_redefinition_of_the_metre …: c = 299,792,456.2±1.1 m/s. However, it's 299,792,458 m/s by convention.

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. Danny Hesman‏ @dannyhesman 17 Jan 2013
        Replying to @neiltyson

        @neiltyson @cmirand4 miles, I've always wondered the speed of gravity. Perhaps it has uncertainty also.

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo
      1. CL‏ @tw1ggs 17 Jan 2013
        Replying to @neiltyson

        @neiltyson @cmirand4 great essay, but I don't think it's the right one to answer the question.

        0 replies 0 retweets 0 likes
        Thanks. Twitter will use this to make your timeline better. Undo
        Undo

    Loading seems to be taking a while.

    Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

      Promoted Tweet

      false

      • © 2018 Twitter
      • About
      • Help Center
      • Terms
      • Privacy policy
      • Cookies
      • Ads info