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Ask A RACHere's how scientists figured out the age of the universe It took some cosmic detective work. by Passant Rabie Oct. 20, 2021 You never ask a cosmic being its age. But if that cosmic being encompasses all of space, time, and matter, you could get a little curious. Scientists have long been curious about the age of the universe and how much time has elapsed since the Big Bang. Today, scientists estimated the age of the universe to be approximately 13.8 billion years old. But how did scientists estimate how old the universe is, and are they sure of that number? It all comes down to ancient stars and the ever-expanding cosmos. How do astronomers calculate the age of the universe? To estimate the age of the universe, scientists rely on two main methods. Calculating the expansion rate of the universe Determining the ages of the oldest stars The Hubble Constant: Since its conception, the universe has been expanding at an accelerating rate. The universe’s expansion rate is known as the Hubble Constant, which is estimated at 46,200 mph per million light-years. The Hubble Constant was first calculated in the 1920s by American astronomer Edwin Hubble after discovering that several galaxies were moving away from Earth. Scientists looked to distant galaxies to measure how fast the universe was expanding. Hubble also noted that the further a galaxy was, the faster it was moving away. Based on Hubble’s observations, the astronomer came up with Hubble’s law which showed a correlation between how far an object is and the speed at which it’s receding. Using Hubble law, scientists were able to estimate the expansion rate of the universe. Scientists were then able to use the Hubble Constant to estimate the age of the universe by working backward, all the way back to the Big Bang. This extrapolation depends on the current density and composition of the universe, which shows the history of its expansion. In 2012 NASA’s Wilkinson Microwave Anisotropy Probe used that data to estimate the universe's age to be 13.772 billion years old, give or take 59 million years. A year later, The European Space Agency’s Planck spacecraft estimated the universe's age to be 13.82 billion years. Ancestral stars: Another way to determine the age of the universe is to look to the oldest stars. The universe can’t be younger than its oldest stars. Therefore, to narrow down the age of the universe, scientists measure the ages of the very first stars that formed in the cosmos. The lifecycle of a star depends on its mass, with high mass stars burning fuel at a faster rate and therefore dying out faster while low mass stars can live up to 20 billion years. Globular clusters are a dense stellar collection of around a million stars which all formed roughly around the same time. These clusters can then serve as timekeepers for the universe. By determining the masses of their stars, scientists can estimate when the globular cluster formed. The oldest globular clusters contain stars that are 0.7 times less massive than the Sun, which suggests that they are between 11 to 18 billion years old. What came before the Big Bang? Scientists can trace the universe back to its explosive birth, the Big Bang. But what happened before this theoretical birth of the cosmos? The universe may have been a singularity, all compact within a form that is smaller than a subatomic particle. It’s difficult to imagine what caused this matter to exist, but one theory even suggests that our universe was born from another universe while another imagines a series of universes being born out of one another like a formation of bubbles. Meanwhile, another theory suggests that the universe goes through an endless cycle of death and rebirth, born from its own demise. How old is the universe in seconds? If the universe is indeed cyclical, then time becomes irrelevant. But just in case you’re still attached to the modern way in which we measure the progression of life, then the age of the universe comes up to about 436,117,076,900,000,000 seconds.How is personal data collected? There are several ways that an unauthorised person can try and collect your data. These include: •phishing •smishing •vishing •pharming. Phishing Phishing is when a person sends a legitimate looking email to a user. The email contains a link to a website that also looks legitimate. The user is encouraged to click the link and to input personal data into a form on the website. The email could also simply ask the user to reply to the email with their personal data. The user is tricked into giving their personal data to a source that they believe is legitimate. However, both the email and the linked website are from a fake unauthorised source. The personal data that is input is then collected by an unauthorised person. This person can then use this data for criminal acts, for example, to commit fraud or steal the person's identity. Intimidation has become a common feature of phishing emails, threatening the user that they must click the link and rectify a situation immediately, or there will be a further issue. The aim of a phishing attack is to steal the user's personal data. Figure 5.1: Phishing. A real-life example of phishing PayPal have been the subject of several different phishing emails. Users receive an email that looks as though it has been sent from PayPal, as it has the PayPal branding. The email normally warns of an issue such as unexpected activity on their account, or that some kind of verification of their account is required. The user is then asked to click a link to log into their account and resolve the issue. The link takes them to a webpage that looks like the PayPal login page. If the user inputs their login details into this page, they will not be taken to their account. It is often at this stage that the user may realise that the email and webpage are fake. However, they have already given the unauthorised person their PayPal login details. Figure 5.2: An example of a phishing email claiming to be from PayPal. How to recognise phishing There are several guidelines to be aware of regarding emails to avoid being subjected to phishing. These include: •Don't even open an email that is not from a sender that you recognise or a trusted source. •Legitimate companies will never ask you for your personal data using email. Be immediately suspicious of any email that requests your personal data. •Legitimate companies will normally address you by your name. Be suspicious of any email that addresses you as ‘Dear Member' or ‘Dear Customer'. •Legitimate companies will send an email that uses their domain name. If you hover your mouse over the sender's name, it will show the email address that the email is sent from. If this does not look legitimate, for example, does not contain the correct domain name, then it is probably fake. For example, if the sender's email is user@paypal1.com rather than user@paypal.com, this is from an incorrect domain name. •Legitimate companies are protective of their professional reputation and thoroughly check any communications. They will make sure that all information given is grammatically and correctly spelt. Be suspicious of any email that contains bad grammar or spelling mistakes. •A link in an email from a legitimate company will also normally contain the domain name of the company. You can sometimes hover over the link, or right click and inspect the link, to see the address of the URL that is attached. If the URL does not contain the domain name, or also contains typical errors such as spelling mistakes, then be suspicious of this. PRACTICAL ACTIVITY 5.02 Ask a friend or a member of your family if they have ever received an email that they believed was a phishing email. Ask them how they identified it was phishing. Ask them if they know all of the given guidelines for identifying phishing emails. Smishing Smishing (or SMS phishing) is a variant of phishing that uses SMS text messages to lure the user into providing their personal details. The user is sent an SMS text message that either contains a link to a website, in the same way that phishing does, or it will ask the user to call a telephone number to resolve an urgent issue. The same advice can be followed for smishing as given for phishing. The user must question at all times any links that are sent from an unknown or suspicious user. It is advisable that if a user believes the message may be legitimate, to type in the domain name for the legitimate company website into their web browser, rather than following the link in the message. Users should block any numbers that they believe are suspicious to prevent any further risk of smishing from that number. Figure 5.3: Smishing. Vishing Vishing (or voice phishing) has the same aim as phishing, to obtain a user's personal details. The user receives a telephone call that could either be an automated system or could be a real person. An automated voice could speak to the user and advise them that an issue has occurred, such as there has been suspicious activity regarding their bank account. The user may then be asked to call another number, or just to simply press a digit and be directed to another automated system. This system will ask them to provide their bank account details to resolve the issue. The bank account details have then been obtained by the unauthorised user and can be used to commit a crime against the user. The automated system could be replaced by a real person who will try to do the same thing. They will try to convince the user that there has been an issue with an account they have and to provide the log-in details or PIN for the account to verify who they are so the issue can be resolved. The precaution to take for vishing is that no company will ever call you and ask you to provide any log-in details or PIN details over the telephone. They may ask you to provide other personal information, and if you are in doubt that the person on the other end of the phone is legitimate, it is always advisable to put the phone down and call the company back on a legitimate number that you may already know or can obtain. Figure 5.4: Vishing. Pharming Pharming is when an unauthorised user installs malicious code on a person's hard drive or server. The malicious code is designed to redirect a user to a fake website when they type in the address of a legitimate one. The fake website is designed to look like the legitimate one, to trick the user and make sure they are not aware that their request has been redirected. The user will then enter their personal details into the fake website, believing it is the legitimate one, and the unauthorised person will now have their personal data. A common technique used in pharming is called domain name server (DNS) cache poisoning. This technique exploits vulnerabilities in the DNS and diverts the internet traffic intended for a legitimate server toward a fake one instead. The unauthorised user needs to find a way to install the malicious code on the computer. They often hide the malicious code in an email attachment or link. When the user opens the email attachment or clicks the link, the malicious code is downloaded also. Figure 5.5: Pharming. The aim of a pharming attack is also to steal a user's personal data. A real-life example of pharming In 2007 50 different companies all over the world were subject to a pharming attack, these included PayPal, eBay, Barclays bank and American Express. Over a three-day period, hackers managed to infect over 1000 PCs a day with a malicious pharming code. When users who had been infected visited the websites of the different companies, they were redirected to a legitimate-looking version of the site that was designed to steal their personal data. The original email, containing the malicious code, was set up to look like a shocking news story. Users were encouraged to click a link in the email to find out more information. The code was downloaded when the user clicked the link. This was quite a sophisticated attack that required legitimate looking websites to be set up for a large number of companies. It is not known how much money the hackers were able to retrieve as a result. How to prevent pharming All of the guidelines to avoid being subjected to phishing are also relevant for recognising pharming. There are also several other precautions that can be taken to check for pharming attacks. These include: •Have a firewall installed and operational. A firewall monitors incoming and outgoing traffic from your computer. It checks this traffic against set criteria and will flag and stop any traffic that does not meet the criteria. A firewall could detect and block suspicious traffic, such as a malicious code trying to enter your system. •Have an anti-virus program installed that is designed to detect malicious pharming code. You need to scan your computer on a regular basis to check for any malicious code. It is advisable to set up an automatic scan on a daily basis at a time when your computer will normally be switched on. •Be aware when using public Wi-Fi connections. A hacker could look to directly access your computer and install the malicious code if you are connected to a public Wi-Fi connection. It is often advisable to use a VPN when using public Wi-Fi. This will help shield your internet activity and personal details from a hacker, making it more difficult for them to access your computer. Smishing can also be used as a form of pharming. A user is sent a link, that when they click is designed to download malware onto their mobile device. Therefore, it is advisable to have security software installed on your mobile and also scan it regularly to detect any presence of malware.Classroom Expectations and Policies Assessment 1. What should students bring to class every day? a. Only a positive attitude b. Charged Chromebook, writing utensil, and positive attitude c. Just their books d. Snacks and drinks 2. What is the consequence for bullying in the classroom? a. A warning b. A violation card c. Extra homework d. A meeting with the principal 3. If a student breaks a personal item, what must they do? a. Ignore it b. Apologize c. Buy a new one for the teacher d. Ask for forgiveness 4. How should students handle using the futon during class? a. Sit on it every day b. Use it without asking c. Ask first and only use it during work time d. Sit on it during lectures 5. Where will all assignments be posted? a. On the classroom wall b. On Canvas c. Only verbally d. In a textbook 6. What happens if an assignment is submitted late? a. It will be graded normally b. It will not be accepted c. It will drop a letter grade each day it is late d. It will be given extra credit 7. After how many days of lateness will a student receive only half credit for an assignment? a. 1 day b. 2 days c. 3 days d. 4 days 8. What is the policy for retaking tests? a. No retakes allowed b. Students must schedule the retake themselves c. Retakes are given automatically d. Only the teacher can decide on retakes 9. What constitutes cheating in this classroom? a. Asking for help b. Claiming credit for someone else's work c. Working with a partner d. Participating in study groups 10. What is the penalty for cheating? a. A warning b. A failing grade on the assignment and notification of parents c. Extra assignments d. A detention 11. How will grades be determined? a. By participation only b. By points, with tests and quizzes weighted more than classwork c. By effort d. By attendance 12. Where can students use their cell phones? a. In class anytime b. In the commons and hallways during passing time and lunch c. In the restroom d. In the cafeteria only 13. What happens if a student uses their phone during class? a. They will receive a warning b. The phone will be confiscated immediately c. They can keep it if they ask d. They will lose points on their grade 14. What should a student do if they know they will be absent? a. Ignore it and hope for the best b. Come to the teacher at least three days before c. Ask a friend for notes d. Just show up later 15. If a student is sick and cannot do work, what should they focus on? a. Completing all missed assignments b. Getting better c. Emailing the teacher every hour d. Asking for extra credit 16. What is the policy on bringing food or drinks to class? a. It's not allowed at all b. It’s allowed as long as it’s not a distraction c. Only water is allowed d. Students must share their food 17. How should students contact the teacher with questions? a. Only during class time b. Through social media c. By email or in person d. By sending a friend 18. What happens if a student emails after 9 PM? a. The teacher will respond immediately b. The teacher will respond the next day at 7:45 AM c. The email will be ignored d. The teacher will call the student 19. How do violations accumulate for cell phone use? a. They reset every trimester b. They accumulate throughout the school year c. They reset every week d. They do not count 20. What should students do if they have concerns while the teacher is on maternity leave? a. Contact the principal b. Contact the substitute teacher for assistance c. Wait until the teacher returns d. Handle it on their own Answer Key (Always review AI generated answers for accuracy - Math is more likely to be inaccurate) b. Charged Chromebook, writing utensil, and positive attitude b. A violation card c. Buy a new one for the teacher c. Ask first and only use it during work time b. On Canvas c. It will drop a letter grade each day it is late c. 3 days b. Students must schedule the retake themselves b. Claiming credit for someone else's work b. A failing grade on the assignment and notification of parents b. By points, with tests and quizzes weighted more than classwork b. In the commons and hallways during passing time and lunch b. The phone will be confiscated immediately b. Come to the teacher at least three days before b. Getting better b. It’s allowed as long as it’s not a distraction c. By email or in person b. The teacher will respond the next day at 7:45 AM b. They accumulate throughout the school year b. Contact the substitute teacher for assistance Miss Jill: Timmy, please stand up and show me the letter C. Timmy: This is the letter C. Miss Jill: Good job, Timmy! Please sit down. Timmy: Thank you, Ms. Jill. Miss Jill: Now I will ask a question. What word begins with the letter C? Timmy: Car! Miss Jill: Good answer! Miss Jill: Everyone, please write down the word "car" in your books. Timmy: Yes, Ms. Jill.Ask me a question about the United States and choose the correct answer yourselfI am a Norwegian teacher teaching how to survive at a restaurant in Paris. How to order, be polite, ask for a table, ask for the bill, choose from the menu both food and drinks for a 5 course meal.. They must transkate from English to French when answering the questions.Toby, can I ask you a question? Yes, go ahead. Do you have any plans after school? Yes, I am going to play football. Cindy, can I ask you a question? Yes, go ahead. Do you know the answer to this Math problem? Sorry, I don’t know the answer.