Welcome to DU!
The truly grassroots left-of-center political community where regular people, not algorithms, drive the discussions and set the standards.
Join the community:
Create a free account
Support DU (and get rid of ads!):
Become a Star Member
Latest Breaking News
General Discussion
The DU Lounge
All Forums
Issue Forums
Culture Forums
Alliance Forums
Region Forums
Support Forums
Help & Search
Science
Related: About this forumInge Lehmann: the Danish scientist who discovered Earth has a solid inner core
Between 1929 and 1939, seismologist Inge Lehmann compared various data sets from earthquakes to conclusively prove what was at the Earth's core.
By Brian Clegg
29th May, 2020 at 00:00
On 17 June 1929, at around 10:17 local time, a 7.3-magnitude earthquake struck the South Island of New Zealand. Waves from the quake were recorded on seismometers around the world, notably in Frankfurt, Copenhagen, Baku, Sverdlovsk and Irkutsk.
These devices consisted of a heavy weight, suspended from a frame.
When the Earth and the frame vibrated, the inertia of the weight prevented it from moving with them, creating a difference in motion that could be captured by a pen on a rolling sheet of paper.
The first accurate seismometers responded to up and down movements in a horizontal arm, but shortly before the New Zealand earthquake, a new kind of seismometer using a vertically suspended weight came into play, and these proved crucial in the discovery.
More:
https://www.sciencefocus.com/planet-earth/inge-lehmann-who-discovered-earth-has-a-solid-inner-core/
InfoView thread info, including edit history
TrashPut this thread in your Trash Can (My DU » Trash Can)
BookmarkAdd this thread to your Bookmarks (My DU » Bookmarks)
3 replies, 748 views
ShareGet links to this post and/or share on social media
AlertAlert this post for a rule violation
PowersThere are no powers you can use on this post
EditCannot edit other people's posts
ReplyReply to this post
EditCannot edit other people's posts
Rec (7)
ReplyReply to this post
3 replies
= new reply since forum marked as read
Highlight:
NoneDon't highlight anything
5 newestHighlight 5 most recent replies
Inge Lehmann: the Danish scientist who discovered Earth has a solid inner core (Original Post)
Judi Lynn
Jun 2020
OP
bobbieinok
(12,858 posts)1. Thanks for posting. Info about yet another 'unknown' woman scientist
bobbieinok
(12,858 posts)2. Wow! She lived to be over 104----1888 to1993 per wikipedia
soothsayer
(38,601 posts)3. Awesome