3 ms·

900000 km/h = 250 km/s. This is fast but comparable to 224 km/s that the sun moves. Our galaxy itself moves at ~600 km/s relative to local cluster center of mas

by ivalm 6y ago

900000 km/h = 250 km/s. This is fast but comparable to 224 km/s that the sun moves. Our galaxy itself moves at ~600 km/s relative to local cluster center of mass.

jojobas 6y ago
The Sun is way slower in regards to neighboring stars. 250 km/s is an order of magnitude faster than Sun/Alpha Centauri relative speed.
- Aperocky 6y ago
  Yep, there's no true reference frame in the universe - Einstein realized that more than 100 years ago and put it down as the theory of relativity.
  - ivalm 6y ago
    Microwave background provides a kind of reference frame for the universe. We are moving ~370km/s relative to it [0]. We are fairly certain CMB is homogenous so this reference frame is same everywhere. [0] https://en.m.wikipedia.org/wiki/Cosmic_microwave_background https://en.m.wikipedia.org/wiki/Cosmic_microwave_background
- ivalm 6y ago
  Edit: checked the actual paper, 250 is relative to galactic center, just like my sun number [0] [0] https://watermark.silverchair.com/staa1761.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAApkwggKVBgkqhkiG9w0BBwagggKGMIICggIBADCCAnsGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMQjn01zD6JL4iHVhBAgEQgIICTC5U1KkQ8V28pu0e5ywTUXk7yyPjV0xKga4ckJCYCESMESq4xQ2v4juLQfGL8U7pvZG9Qr8TTQh6lTLLYoW8hZeeG25CCDdedZq-ORuIjRmGY7OdjeVuTXcwYOE-BJt5adB9QRjLw9mOtzLB3hrQuqrqfQf_Ddi5w0YKboESJTM2q9z3K8Gws7vmov4La4FJ6pg8Y0qBMzG-khSXhyr1Qaili203WHJUZo1iaFa_LZqN0AqjMJAs6dPduY6CRAarUXrCvpVWIpPYecwOX_YkLXWXVPZ9htz7W_UBHhXtjIYduJ8svRn6YscdOZyKEQktZ7NG_ufbPTLtZY1T_wO5sQdSLPHIyJSlDZBCk_mhSlcuekAmKEViDrxzRxYb7oWuLy5JUVX7qiLZXWRovQB_MEusQc8uOjg-76-pkTM3ouibG2yzmic_HR4S9jQYpyLzMr5cy3VdE-ROdOOadS6z9wBHQ8ZK2phteGYEGVOgoJephcc5Zy-4jueg4TVXInenn74kySZJv1rwEY6bojhe3uqirPre6UwQhdm8yfSyU8-uk3HlZZkUOS439zZDZ-HhXS4CEwQKzHlT_6azPBBgGYF1-y0bax34nF5JbNT577DqFSGYAvlW21sX7ip8fSLHKGdhctBHfpvbllCf1-FGGeTQt9qSpZ1NeTq6naPGGFLv1D158MKTpkj0ZgrHcBC69hkhLP9GChdigiH5NUwnInQxM3ux4Z8t3ufaR9q2GqVttathEL13c40t0Ou_cu2Eg0SJgep6j5DYb8xdLQ https://watermark.silverchair.com/staa1761.pdf?token=AQECAHi... We are in a milky way, it is reasonable to look at the speed relative to the galactic nucleus, which is what I did. Kind of how we talk about speed of earth/comets/etc around the sun.
lmilcin 6y ago
Those speeds are not comparable. If you search for high speed differences, you just look for far enough target. It is much more impressive for any body to generate its own delta V than to follow an orbit. This is the reason why you discuss cars moving at tens of meters per second forgetting that they are already moving at over 200km/s around our Galaxy. Because some reference frames just aren't interesting.
- ivalm 6y ago
  The velocity of the star in the paper, and our star, are both with respect to galactic nucleus. The star is still following orbit, just presumably a very eccentric one. I never said it is not impressive, just that it is similar to typical orbital velocities in our galaxy. The eccentricity of the orbit is the atypical thing here.

by ivalm 6y ago

900000 km/h = 250 km/s. This is fast but comparable to 224 km/s that the sun moves. Our galaxy itself moves at ~600 km/s relative to local cluster center of mass.

jojobas 6y ago

The Sun is way slower in regards to neighboring stars. 250 km/s is an order of magnitude faster than Sun/Alpha Centauri relative speed.

Aperocky 6y ago
Yep, there's no true reference frame in the universe - Einstein realized that more than 100 years ago and put it down as the theory of relativity.
- ivalm 6y ago
  Microwave background provides a kind of reference frame for the universe. We are moving ~370km/s relative to it [0]. We are fairly certain CMB is homogenous so this reference frame is same everywhere. [0] https://en.m.wikipedia.org/wiki/Cosmic_microwave_background https://en.m.wikipedia.org/wiki/Cosmic_microwave_background
ivalm 6y ago
Edit: checked the actual paper, 250 is relative to galactic center, just like my sun number [0] [0] https://watermark.silverchair.com/staa1761.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAApkwggKVBgkqhkiG9w0BBwagggKGMIICggIBADCCAnsGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMQjn01zD6JL4iHVhBAgEQgIICTC5U1KkQ8V28pu0e5ywTUXk7yyPjV0xKga4ckJCYCESMESq4xQ2v4juLQfGL8U7pvZG9Qr8TTQh6lTLLYoW8hZeeG25CCDdedZq-ORuIjRmGY7OdjeVuTXcwYOE-BJt5adB9QRjLw9mOtzLB3hrQuqrqfQf_Ddi5w0YKboESJTM2q9z3K8Gws7vmov4La4FJ6pg8Y0qBMzG-khSXhyr1Qaili203WHJUZo1iaFa_LZqN0AqjMJAs6dPduY6CRAarUXrCvpVWIpPYecwOX_YkLXWXVPZ9htz7W_UBHhXtjIYduJ8svRn6YscdOZyKEQktZ7NG_ufbPTLtZY1T_wO5sQdSLPHIyJSlDZBCk_mhSlcuekAmKEViDrxzRxYb7oWuLy5JUVX7qiLZXWRovQB_MEusQc8uOjg-76-pkTM3ouibG2yzmic_HR4S9jQYpyLzMr5cy3VdE-ROdOOadS6z9wBHQ8ZK2phteGYEGVOgoJephcc5Zy-4jueg4TVXInenn74kySZJv1rwEY6bojhe3uqirPre6UwQhdm8yfSyU8-uk3HlZZkUOS439zZDZ-HhXS4CEwQKzHlT_6azPBBgGYF1-y0bax34nF5JbNT577DqFSGYAvlW21sX7ip8fSLHKGdhctBHfpvbllCf1-FGGeTQt9qSpZ1NeTq6naPGGFLv1D158MKTpkj0ZgrHcBC69hkhLP9GChdigiH5NUwnInQxM3ux4Z8t3ufaR9q2GqVttathEL13c40t0Ou_cu2Eg0SJgep6j5DYb8xdLQ https://watermark.silverchair.com/staa1761.pdf?token=AQECAHi... We are in a milky way, it is reasonable to look at the speed relative to the galactic nucleus, which is what I did. Kind of how we talk about speed of earth/comets/etc around the sun.

lmilcin 6y ago

Those speeds are not comparable. If you search for high speed differences, you just look for far enough target. It is much more impressive for any body to generate its own delta V than to follow an orbit. This is the reason why you discuss cars moving at tens of meters per second forgetting that they are already moving at over 200km/s around our Galaxy. Because some reference frames just aren't interesting.

ivalm 6y ago
The velocity of the star in the paper, and our star, are both with respect to galactic nucleus. The star is still following orbit, just presumably a very eccentric one. I never said it is not impressive, just that it is similar to typical orbital velocities in our galaxy. The eccentricity of the orbit is the atypical thing here.