E=mc2, Einstein’s famous equation from his theory of special relativity, tells us that matter and energy are somehow the same. This is the basis of nuclear power; mass can be transformed into light and heat.
But can energy act like mass, specifically in regards to gravity? According to Einstein’s general theory of relativity, yes.
Even the gravitational energy that binds the Earth together is affected by gravity. This follows from the strong equivalence principle, which says that all forms of matter are affected by gravity in the same way, regardless of what they are made of or where you do the experiment.
But it is a very hard principle to test, because the “mass” due to the gravitational binding energy of most things is tiny compared to an object’s ordinary mass. For the Earth, the contribution is less than one part in a billion.
I am part of an international team of scientists led by Scott Ransom of the US National Radio Astronomy Observatory which is surveying the sky with the Green Bank Telescope in West Virginia for exotic stars called pulsars.
Recently, we discovered a stellar system that provides an excellent way of testing the strong equivalence principle.
This system is made up of a pulsar orbited by a white dwarf every one and a half days, with a second white dwarf orbiting them both every 327 days.
A white dwarf is the leftover core of a Sun-like star which has gone through all the phases of its life. It is about the size of Earth, but 100,000 times as massive – so the gravitational force at the surface is 100,000 times that of Earth.
But that is still considered weak. The pulsar has the strong gravitational field. A pulsar is the collapsed core of a very massive star which is left behind after a supernova explosion.
The densest object that can exist without collapsing into a black hole, it packs more than the mass of the Sun into a sphere about 25 kilometers across.
Gravity on a pulsar’s surface is 100 billion times stronger than on Earth, and a pulsar’s gravitational binding energy is more than 10 per cent of its mass.
We still need a way of measuring the motions of the three bodies, and this is where pulsars really shine.
They have incredibly strong magnetic fields and rotate extremely quickly. This rotation accelerates charged particles that beam radio waves in particular directions in space, like a lighthouse casting light over the ocean.
When the beam is pointed towards Earth, we detect a radio pulse. These pulses work like the tick of a celestial clock, which we measure to an accuracy of a millionth of a second.
Motions of the pulsar towards and away from us due to its complex dance with the two white dwarfs cause variations in the times these pulses reach Earth, allowing us to determine the orbits of the three objects with extraordinary precision.
In this way, we can look for differences in how the pulsar and the inner white dwarf “fall” towards the outer white dwarf. Any difference would indicate that the strong equivalence principle does not hold.
But why try so hard to test an obscure principle? Because Einstein’s general theory of relativity is incompatible with the other great physics theory of the 20th century, quantum mechanics.
Einstein himself was aware of this incompatibility. He spent much of his later life trying to reconcile the two theories, and failed – and physicists are still struggling with the problem.
There is no accepted “theory of everything” that can accommodate both. Most approaches to the problem require some sort of modification to general relativity, and many possibilities have already been ruled out.
While the theories vary, almost every proposed alternative to general relativity that might allow quantum mechanics to work violates of the strong equivalence principle.
So we will keep observing this system, looking for small deviations to what is expected from ordinary gravity.
If we do not see any, it will be even harder to reconcile quantum mechanics and gravity.
But if we do, then we will finally have evidence that there really is something wrong with Einstein’s theory of gravity, and be one step closer to solving the greatest problem in theoretical physics.
Mallory Roberts is visiting professor of practice of physics at NYU Abu Dhabi.
The biog
Favourite colour: Brown
Favourite Movie: Resident Evil
Hobbies: Painting, Cooking, Imitating Voices
Favourite food: Pizza
Trivia: Was the voice of three characters in the Emirati animation, Shaabiyat Al Cartoon
A fraudulent investment operation where the scammer provides fake reports and generates returns for old investors through money paid by new investors, rather than through ligitimate business activities.
Mercer, the investment consulting arm of US services company Marsh & McLennan, expects its wealth division to at least double its assets under management (AUM) in the Middle East as wealth in the region continues to grow despite economic headwinds, a company official said.
Mercer Wealth, which globally has $160 billion in AUM, plans to boost its AUM in the region to $2-$3bn in the next 2-3 years from the present $1bn, said Yasir AbuShaban, a Dubai-based principal with Mercer Wealth.
“Within the next two to three years, we are looking at reaching $2 to $3 billion as a conservative estimate and we do see an opportunity to do so,” said Mr AbuShaban.
Mercer does not directly make investments, but allocates clients’ money they have discretion to, to professional asset managers. They also provide advice to clients.
“We have buying power. We can negotiate on their (client’s) behalf with asset managers to provide them lower fees than they otherwise would have to get on their own,” he added.
Mercer Wealth’s clients include sovereign wealth funds, family offices, and insurance companies among others.
From its office in Dubai, Mercer also looks after Africa, India and Turkey, where they also see opportunity for growth.
Wealth creation in Middle East and Africa (MEA) grew 8.5 per cent to $8.1 trillion last year from $7.5tn in 2015, higher than last year’s global average of 6 per cent and the second-highest growth in a region after Asia-Pacific which grew 9.9 per cent, according to consultancy Boston Consulting Group (BCG). In the region, where wealth grew just 1.9 per cent in 2015 compared with 2014, a pickup in oil prices has helped in wealth generation.
BCG is forecasting MEA wealth will rise to $12tn by 2021, growing at an annual average of 8 per cent.
Drivers of wealth generation in the region will be split evenly between new wealth creation and growth of performance of existing assets, according to BCG.
Another general trend in the region is clients’ looking for a comprehensive approach to investing, according to Mr AbuShaban.
“Institutional investors or some of the families are seeing a slowdown in the available capital they have to invest and in that sense they are looking at optimizing the way they manage their portfolios and making sure they are not investing haphazardly and different parts of their investment are working together,” said Mr AbuShaban.
Some clients also have a higher appetite for risk, given the low interest-rate environment that does not provide enough yield for some institutional investors. These clients are keen to invest in illiquid assets, such as private equity and infrastructure.
“What we have seen is a desire for higher returns in what has been a low-return environment specifically in various fixed income or bonds,” he said.
“In this environment, we have seen a de facto increase in the risk that clients are taking in things like illiquid investments, private equity investments, infrastructure and private debt, those kind of investments were higher illiquidity results in incrementally higher returns.”
The Abu Dhabi Investment Authority, one of the largest sovereign wealth funds, said in its 2016 report that has gradually increased its exposure in direct private equity and private credit transactions, mainly in Asian markets and especially in China and India. The authority’s private equity department focused on structured equities owing to “their defensive characteristics.”
Scoreline
Switzerland 5
THE LIGHT
Director: Tom Tykwer
Starring: Tala Al Deen, Nicolette Krebitz, Lars Eidinger
Rating: 3/5
Other workplace saving schemes
The UAE government announced a retirement savings plan for private and free zone sector employees in 2023.
National Bonds unveiled a Golden Pension Scheme in 2022 to help private-sector foreign employees with their financial planning.
In April 2021, Hayah Insurance unveiled a workplace savings plan to help UAE employees save for their retirement.
Lunate, an Abu Dhabi-based investment manager, has launched a fund that will allow UAE private companies to offer employees investment returns on end-of-service benefits.
Company profile
Date started: 2015
Founder: John Tsioris and Ioanna Angelidaki
Based: Dubai
Sector: Online grocery delivery
Staff: 200
Funding: Undisclosed, but investors include the Jabbar Internet Group and Venture Friends
The Baha'i faith was made known in Yemen in the 19th century, first introduced by an Iranian man named Ali Muhammad Al Shirazi, considered the Herald of the Baha'i faith in 1844.
The Baha'i faith has had a growing number of followers in recent years despite persecution in Yemen and Iran.
Today, some 2,000 Baha'is reside in Yemen, according to Insaf.
"The 24 defendants represented by the House of Justice, which has intelligence outfits from the uS and the UK working to carry out an espionage scheme in Yemen under the guise of religion.. aimed to impant and found the Bahai sect on Yemeni soil by bringing foreign Bahais from abroad and homing them in Yemen," the charge sheet said.
Baha'Ullah, the founder of the Bahai faith, was exiled by the Ottoman Empire in 1868 from Iran to what is now Israel. Now, the Bahai faith's highest governing body, known as the Universal House of Justice, is based in the Israeli city of Haifa, which the Bahais turn towards during prayer.
The Houthis cite this as collective "evidence" of Bahai "links" to Israel - which the Houthis consider their enemy.
Your UK residence status is assessed using the statutory residence test. While your residence status – ie where you live - is assessed every year, your domicile status is assessed over your lifetime.
Your domicile of origin generally comes from your parents and if your parents were not married, then it is decided by your father. Your domicile is generally the country your father considered his permanent home when you were born.
UK residents who have their permanent home ("domicile") outside the UK may not have to pay UK tax on foreign income. For example, they do not pay tax on foreign income or gains if they are less than £2,000 in the tax year and do not transfer that gain to a UK bank account.
A UK-domiciled person, however, is liable for UK tax on their worldwide income and gains when they are resident in the UK.
THE SPECS
Engine: 6.75-litre twin-turbocharged V12 petrol engine