Understanding the Early Universe Depends on Estimating the Lifespan of Neutrons – Universe Today
[ad_1]
When we look into the night sky, we see the universe as it once was. We know that in the past the universe was once warmer and denser than it is now. When we look deep enough into the sky, we see the microwave remnant of the big bang known as the cosmic microwave background. That marks the limit of what we can see. It marks the extent of the observable universe from our vantage point.
The cosmic background we observe comes from a time when the universe was already about 380,000 years old. We can’t directly observe what happened before that. Much of the earlier period is fairly well understood given what we know about physics, but the earliest moments of the big bang remain a bit of a mystery. According to the standard model, the earliest moments of the universe were so hot and dense that even the fundamental forces of the universe acted differently than they do now. To better understand the big bang, we need to better understand these forces.
One of the more difficult forces to understand is the weak force. Unlike more familiar forces such as gravity and electromagnetism, the weak is mostly seen through its effect of radioactive decay. So we can study the weak force by measuring the rate at which things decay. But there’s a problem when it comes to neutrons.
Together with protons, neutrons make up the nuclei of the atoms we see around us. Within an atomic nucleus, neutrons can be extremely stable. But when a neutron is on its own, it typically decays in a matter of minutes. The rate of decay for neutrons is typically given in terms of its half life. That is, the time at which a neutron has about a 50/50 chance of having decayed. Technically, they measure a related quantity known as the neutron lifetime, but the idea is the same.
There are a couple of ways we can measure neutron half-life, such as measuring a beam of neutrons or cooling them down and trapping them in a magnetic bottle, but these different methods give different results for the half-life. The methods should give the same result, but they don’t. The beam method gives a lifetime of 888 seconds, while the bottle method gives 879 seconds. Perhaps there is some systematic error in the methods, but this discrepancy is a problem for fundamental physics. But a new study has measured neutron decay in a third way, by using a spacecraft orbiting the Moon.
The airless surface of the moon is constantly bombarded by cosmic rays. Sometimes a cosmic ray will kick a neutron off the lunar surface. As the neutron speeds away from the Moon, it has a chance of decaying. So the team used NASA’s Lunar Prospector satellite to count the number of neutrons at various orbital heights. From this, they calculated the neutron lifetime to be 887 seconds.
The result isn’t precise enough to resolve the neutron decay problem, but it does show that we can use spacecraft to get very accurate results. Accurate enough that future missions might be able to solve the weakest link of early cosmology.
Reference: Wilson, Jack T., et al. “Measurement of the free neutron lifetime using the neutron spectrometer on NASA’s Lunar Prospector mission.” Physical Review C 104.4 (2021): 045501.
[ad_2]
Original Post
Simply desire to say your article is as astounding. The clearness for your put up is simply excellent and i can think you are a professional on this subject. Well along with your permission let me to grab your feed to keep updated with impending post. Thank you 1,000,000 and please carry on the rewarding work.
This actually answered my problem, thanks!
You made some nice points there. I looked on the internet for the subject matter and found most people will consent with your blog.
Wow! This can be one particular of the most helpful blogs We have ever arrive across on this subject. Basically Excellent. I’m also a specialist in this topic therefore I can understand your effort.
You made some nice points there. I did a search on the subject matter and found most people will agree with your website.
certainly like your website but you need to test the spelling on several of your posts. Many of them are rife with spelling problems and I find it very bothersome to tell the truth then again I¦ll surely come back again.
Some genuinely excellent info , Gladiola I detected this.
I’ve been absent for some time, but now I remember why I used to love this blog. Thank you, I will try and check back more often. How frequently you update your site?
Excellent post. I was checking continuously this blog and I’m impressed! Extremely helpful information particularly the last part 🙂 I care for such information much. I was looking for this certain info for a long time. Thank you and best of luck.
Utterly composed written content, Really enjoyed studying.
Pretty nice post. I simply stumbled upon your blog and wished to mention that I have really enjoyed browsing your blog posts. In any case I will be subscribing for your feed and I hope you write again soon!
I have been absent for some time, but now I remember why I used to love this blog. Thank you, I will try and check back more frequently. How frequently you update your website?
Thanks for some other informative blog. The place else may I get that kind of info written in such a perfect manner? I have a project that I’m just now working on, and I have been at the look out for such information.
Thanks for the sensible critique. Me & my neighbor were just preparing to do some research about this. We got a grab a book from our area library but I think I learned more from this post. I’m very glad to see such fantastic information being shared freely out there.
I’m not sure why but this blog is loading extremely slow for me. Is anyone else having this problem or is it a problem on my end? I’ll check back later and see if the problem still exists.
hello!,I like your writing very so much! share we communicate more about your article on AOL? I need a specialist on this space to resolve my problem. Maybe that’s you! Taking a look forward to peer you.
There is obviously a bunch to identify about this. I assume you made certain good points in features also.
Sweet internet site, super design and style, real clean and use pleasant.
I like this post, enjoyed this one appreciate it for putting up. “No trumpets sound when the important decisions of our life are made. Destiny is made known silently.” by Agnes de Mille.
I see something really special in this internet site.
Super-Duper site! I am loving it!! Will be back later to read some more. I am bookmarking your feeds also.
I’m still learning from you, while I’m trying to reach my goals. I certainly liked reading all that is written on your site.Keep the posts coming. I loved it!
I like this post, enjoyed this one regards for putting up. “Fear not for the future, weep not for the past.” by Percy Bysshe Shelley.
Saved as a favorite, I really like your blog!
Yay google is my world beater aided me to find this great internet site! .
Those are yours alright! . We at least need to get these people stealing images to start blogging! They probably just did a image search and grabbed them. They look good though!
Hiya, I’m really glad I have found this info. Nowadays bloggers publish just about gossips and internet and this is actually frustrating. A good blog with exciting content, that is what I need. Thank you for keeping this web-site, I will be visiting it. Do you do newsletters? Can not find it.
You made some first rate points there. I regarded on the web for the difficulty and found most people will go along with together with your website.
Thank you, I have recently been searching for information about this subject for a while and yours is the greatest I have found out so far. But, what about the conclusion? Are you positive concerning the source?
Regards for all your efforts that you have put in this. very interesting information.
Its like you read my mind! You seem to know a lot about this, like you wrote the book in it or something. I think that you can do with some pics to drive the message home a little bit, but other than that, this is great blog. An excellent read. I will definitely be back.
Hey, you used to write fantastic, but the last several posts have been kinda boringK I miss your super writings. Past several posts are just a bit out of track! come on!
It¦s actually a great and useful piece of info. I am glad that you simply shared this helpful info with us. Please stay us informed like this. Thanks for sharing.
What is FlowForce Max? FlowForce Max Advanced Formula is a holistic blend designed to promote optimal prostate health
Great website. A lot of useful information here. I am sending it to some buddies ans additionally sharing in delicious. And of course, thanks to your effort!
of course like your website however you need to take a look at the spelling on several of your posts. Many of them are rife with spelling issues and I find it very troublesome to inform the reality then again I will definitely come again again.
Hi, i think that i saw you visited my blog thus i came to “return the favor”.I’m trying to find things to improve my website!I suppose its ok to use some of your ideas!!
Only a smiling visitant here to share the love (:, btw outstanding pattern. “Treat the other man’s faith gently it is all he has to believe with.” by Athenus.
There is visibly a bunch to realize about this. I consider you made some nice points in features also.
Really excellent information can be found on web site.
I will immediately seize your rss feed as I can not to find your email subscription hyperlink or newsletter service. Do you have any? Please allow me understand in order that I could subscribe. Thanks.
Attractive part of content. I simply stumbled upon your site and in accession capital to assert that I get actually loved account your weblog posts. Anyway I’ll be subscribing on your feeds and even I success you get admission to persistently fast.